NATIONAL BUREAU OF STANDARDS REPORT

399^

ROOF MAINTENANCE MANUAL

By

H, R, Snoke and W. C. Cullen

Sponsored by

Repairs and Utilities Division

Office of the Chief of Engineers

Department of the Army

and

Maintenance Division

Bureau of Yards and Docks

Department of the Navy

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards is suggested in the following listing

of the divisions and sections engaged in technical work. In general, each section is engaged in

specialized research, development, and engineering in the field indicated by its title. A brief

description of the activities, and of the resultant reports and publications, appears on the inside

of the back cover of this report.

Electricity and Electronics, Resistance and Reactance. Electron Tubes. Electrical Instru- ments. Magnetic Measurements. Process Technology. Engineering Electronics. Electronic

Instrumentation. Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Optical Instruments. Photographic

Technology. Length. Engineering Metrology.

Heat and Power. Temperature Measurements, Thermodynamics. Cryogenic Physics.

Engines and Lubrication. Engine Fuels.

Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid

State Physics. Electron Physics. Atomic Physics. Nuclear Physics. Radioactivity, X-rays. Betatron. Nucleonic Instrumentation. Radiological Equipment. AEC Radiation Instruments. Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry, Thermochemistry. Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics.

Mass and Scale. < Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper, Leather, Testing and Specifications. Polymer Structure. Organic Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion.

Mineral Products. Porcelain and Pottery. Glass. Refractories. Enameled Metals. Concreting Materials. Constitution and Microstructure.

BuUding Technology. Structural Engineering. Fire Protection. Heating and Air Conditioning. Floor, Roof, and Wall Coverings. Codes and Specifications.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems, Components and Techniques. Digital Circuitry. Digital Systems.

Analogue Systems.

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials.

Gas Liquefaction.

Ra<ii<» I*ropagalioii Physics. Upper Atmosphere Research. Ionospheric Research. Regular

Propagation Services.

Radio Propagation Engineering. Frequency Utilization Research. Tropospheric Propagation

Research.

Radio Standards. High Frequency Standards. Microwave Standards. • Office of Basic Instrumentation • Office of Weights and Measures
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1004- 40-4843 March 22, 19^5 3994

ROOF MAINTENANCE MANUAL

By

Ho Ro Snoke and Wo Co Cullen

Floor, Roof and Wall Coverings Section

Building Technology Division

Sponsored by

Repairs and Utilities Division

Office of the Chief of Engineers

Department of the Army

and

Maintenance Division

Bureau of Yards and Docks

Department of the Navy

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, rep

unless permission Is 25,D.C, Such perr

cally prepared If th

Approved for public release by the "

ndards, Washington

lort has been speclli- Standards and Technology (NIST)lort has been speclhport for Its own use, on October 9, 2015.
/ 1

II

IIaaa
ROOF MAINTENANCE MANUAL

INDEX

Page

INTRODUCTION 1

1»1 Purpose and Scope 1

2. GENERAL DISCUSSION 1

2.1 Importance of Periodic Inspections 1

2.2 Maintenance 2

2.3 Repairs 2

2.4 Reroofing 2

3. CAUSES OF ROOF FAILURES 3

3 cl Lack of Maintenance 3

3.2 Normal Weathering 3

3.3 Use of Unseasoned Lumber 4

3«4 Storage 4- 3.5 Improper Application of Roofing Materials 4

3.6 Use of Improper Materials 6

3 « 7 Wind Damage 7

3.8 Exposed Nails 8

3.9 Failure of Flashings 8

4. TYPES OF ROOFING 8

4.1 Built-Up Roofing 8

4„1.1 Description and General Discussion 9

4.1„2 Roof Decks for Built-Up Roofs 11

4.103 Storage and Handling of Materials 12

4.104 Determining Treatment for Built-Up

Roofs l4

4„1„5 Maintenance Methods - Built-Up Roofs 15

4.1,6

Repair Methods - Built-Up Roofs 22

4„1»7 Reroofing 27

4.1.8 Federal and Military Specifications

Used in Built-Up Roof Construction, Maintenance and Repair 28
INDEX - 2

ko2 Asphalt-Shingle Roofing 29

A, 2.1 Description and General Discussion 29

A, 2, 2 Roof Decks for Asphalt-Shingle Roofs 32

4.2.3 Storage and Handling of Asphalt

Shingles 32

402.4 Determining Treatment for AsphaltShingle Roofs 34

4.2o 5 Maintenance and Repair Methods,

Asphalt-Shingle Roofs 35

4.2.6 Reroofing with Asphalt Shingles 37

4.3 Asphalt Roll Roofing

4 , 3 »1 Description and General Discussion 4l

4 . 3.2 Roof Decks for Asphalt Roll Roofing

Roofs 42

4 . 3.3 Storage and Handling of Asphalt Roll

Roofing 43

4 . 3.4 Determining Treatment for Asphalt

Roll Roofing Roofs 43

4 . 3.5 Maintenance Methods - Asphalt Roll

Roofing 44

4 . 3.6 Repair Methods - Asphalt Roll Roofings 45

4 . 3.7 Reroofing With Roll Roofings 49

4.4 Asbestos-Cement Roofing 49

4.4.1 Description and General Discussion 49

4.4.2 Roof Decks for Asbestos-Cement Roofs 50

4 . 4.3 Storage and Handling of AsbestosCement Roofing 51

4.4.4 Determining Treatment for AsbestosCement Roofs 51

4 . 4.5 Maintenance and Repair Methods - Asbestos-Cement Roofings 52

4.4.6 Reroofing with Asbestos-Cement

Roofing 53
INDEX - 3

4.5

Metal Roofing

4 ,

5.1

Description and General Discussion

4, 5c 2 Roof Decks for Metal Roofings

4 ,

5.3

Storage and Handling of Metal Roofing

4,5®4 Determining Treatment for Metal Roofs

A. Copper Roofing

B. Terne Roofing

C. Galvanized Steel Roofing

D. Aluminum Roofing

E. Protected Metal Roofing

4,6

Slate Roofing

4.6.1 Description and General Discussion

4.6.2 Roof Decks for Slate Roofs

4 . 6.3 Storage and Handling of Slates

4.6.4 Determining Treatment for Slate Roofs

4 . 6.5 Maintenance and Repair Methods - Slate Roofs

4.6.6 Reroofing With Slate

4.7 Tile Roofing

4 . 7.1 Description and General Discussion

4 . 7.2 Decks for Tile Roofs

4 . 7.3 Storage and Handling of Tiles

4 . 7.4 Determining Treatment for Tile Roofs

4 . 7.5 Maintenance and Repair Methods - Tile Roofs

4 . 7.6 Reroofing with Tiles

4.8 Wood-Shingle Roofing

4.8.1 Description and General Discussion

4.8.2 Roof Decks for Wood-Shingle Roofs

4 . 8.3 Storage and Handling of Wood Shingles

4.8.4 Determining Treatment for WoodShingle Roofs

4 . 8.5 Maintenance and Repair Methods - Wood

Shingle Roof s 4.8.6 Reroofing with Wood Shingles

Page

56

56

60

60

61

61

69

71

72

72

73

74

74

75

76

77

77

73

79

79

80

81

83

83

84

85

85

86

88
INDEX - h

FLASHINGS AND APPURTENANCES 91

5.1 Wall, Chimney and Monitor Flashings 91

5.1.1 General Discussion 91

5.1.2 Inspection Procedures 93

5.1.3 Maintenance and Repair Methods 95

5.2 Vent Flashings 98

5.2.1 General Discussion 98

5.2.2 Inspection 99

5.2.3 Maintenance 100

5.2. Repair During Reroofing 101

5.3 Valley Flashings 101

5.3.1 General Discussion 101

5.3.2 Inspection 103

5.3.3 Maintenance and Repair 104

5.^ Drainage Systems 106

5.^.1 General Discussion 106

5A.2 Inspection 106

5.^.3 Maintenance and Repair 107

5o5 Gravel Stops and Metal Edge Strips 109

5.5.1 General Discussion 109

5.5.2 Inspection 110

5.5.3 Maintenance and Repair 111

5.6 other Projections 113

5.6.1 General Discussion 113

5.6.2 Inspection 113

5.6.3 Maintenance and Repair 113
INDEX - 5

Page

6o SAFETY MEASURES ll4

601 General Discussion 11^

602 Storage and Handling of Materials 115

6«3 Ladders 115

6A Scaffolds ll6

6«5 Roof Brackets Il6

6o6 Heating and Handling Bituminous Materials 117

APPENDIX I„ 119

Historical Record Forms

Built-Up Roofs 120

Asphalt-Shingle Roofs 122

Asphalt Roll-Roofing Roofs 12h

Asbestos-Cement Roofs 126

Metal Roofs 128

Slate Roofing 130

Tile Roofing 132

Wood-Shingle Roofs 13^

Inspection Forms

Built-Up Roofs 136

Asphalt-Shingle Roofs l4o

Asphalt Roll-Roofing Roofs 1^2

Asbestos-Cement Roofs 1^^

Metal Roofs l46

Slate Roofs 1^8

Tile Roofs 150

Wood-Shingle Roofs 152

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ROOF MAINTENANCE MANUAL

1. INTRODUCTION

1,1 Purpose and Scope

The purpose of this manual is to provide a guide for an

economical system of roof inspections, maintenance, repairs

and reroofing. For convenience

, ‘‘each type of roofing is

treated in a self-contained section, except for cross references to avoid repetition,

2, GENERAL DISCUSSION

2,1 Importance of Periodic Inspections

The first step in the establishment of a proper roof

maintenance program is the adoption of a periodic inspection

system. The early discovery and (Correction of minor defects

forestalls major repairs and extends materially the date when

reroofing is necessary. Since a large proportion of early

roof failures are flashing failures, the regular inspection

of flashings is of vital Importance, ^ Regular inspections should be made by competent personnel at least once each year, and always in the Spring,

This time is best because it follows ,the severe winter conditions and is followed by the period' best suited for roofing work.

Inspections should be made even 1;^hough a roof has been

exposed for less than one year,_ The first yearly inspection

is of great importance because it frequehi:ly discloses minor

defects that were not apparent when the roofing or i^erooflng

job was completed. - The roof inspection record should be made a part of

the historical file maintained for each structure. This continuing record will be of considerable value in determining

the roof treatment that may be necessary. Suggested forms

for maintaining historical records and for use in inspections

of th^ various kinds of roofs are shown in Appendix I,

In addition to scheduled inspections, inspections must

be made after exposure of the roofs to unusually severe

weather conditions such as very strong winds, hail or longcontinued rain.
- 2 -

2,2 Maintenance

Roof maintenance 5 for the purpose of this manual, is

defined as the treatment given a roof prior to any actual

failure. It may consist in the correction of minor -defects

in small areas, such as resurfacing bare spots in mineral-'

surfaced built-up roofs; or it .may involve treatment of the

entire roof area, such as recoating a smooth- surf aced builtup roof.

The importance of proper roof maintenance cannot be

emphasized too strongly. With good maintenance, roofs do

not leak, the useful life of the roof is extended many

years and the cost per year for roofing is reduced to a

bare minimum.

Some types of roofing require more maintenance than

others, but every establishment should have a well-trained

roof maintenance crew of a size determined by the kinds of

roofing and the roof areas Involved,

2.3 Repairs

Roof repairs, as distinguished from roof maintenance,

are considered to be the treatments given a roof following

at least partial failure. These, too, may be minor repairs

involving small areas, such as the replacement of broken

slate or tile; or they may be major 'repairs involving t^he

whole roof, such as applying additional layers of felt

over a built-up roof.

Minor repairs should be ac^complished by the roof maintenance crew. In mbst cases major repairs should be accomplished by contract with a reliable local roofing contractor.

2,^- Reroofing

Every roof ultimately requires reroofing. While the

main purpose of this manual is to serve as a guide for

extending the useful life of .roofs by proper maintenance

and repair methods^, of equal importance is the development

of criteria for determining the point at which maintenance
” 3

-

and repair treatments become unsound economic§.lly and reroofing is indicated o Many factors enter into this determination, of which some of the most important ares age of the

roofing, unusual exposure conditions such as hail or strong

winds, previous maintenance and repair or lack of these, and

the current and possible future use of the structure* '"It is

only by weighing all of the pertinent factors that a proper

decision can be made.

3o CAUSES OF ROOF FAILURES

3«1 Lack of Maintenance

Failure to recognize and correct minor defects and deterioration in its earliest stages are probably the greatest

causes of premature roof failures. Since the whole theme

of this Manual is roof maintenance , the simple listing of it

as the primary cause of failure suffices here.

3e2 Normal Weathering

All roofing materials deteriorate on exposure to the

weather, the rate of deterioration being determined .largely

by the kind of material and the conditions of exposure,.

Some slate roofs in this country are more than 100

years old; the oldest copper roof is more than 200 years;

and "tin" roofs exposed 80 or more years are not uncommon.

On the other hand, roofs of poor quality slate have been

known to fail in 10 years; copper roofs may fail within

one year through failure to provide for expansion and contraction, though the metal has not deteriorated; and "tin"

roofs deteriorate rapidly when painting Is neglected.

These are only a- few of t^he examples that might be given.

In general, inorganic roofing materials tend to deteriorate

less rapidly on exposure than the organic ones. Metal

roofs subject to rapid oxidation must be protected, i
3o3 Use of Unseasoned Lumber

The use of unseasoned lumber for roof framing and roof

decks is a frequent cause of premature roof failure., Figure 1* illustrates roll roofing torn loose from the warped

sheathing boards. Movement in the roof deck may cause

breakage of rigid roofing materials such as slate, t^le

and asbestos-cement shingles, and unsightly buckles 'in

roll roofings, asphalt shingles and built-up roofs,

3o^ Storage

Roofing materials, though intended for direct exposure

to the weather, may be harmed if exposed before application.

Consequently, roofing materials should be stored under cover

at all times. Similarly, improper storage such as in

direct contact with the ground or in stacks that are too

high may damage the roofing material.

3.5 Improper Application of Roofing Materials

Workmanship in applying roofing materials is as important as the selection of the proper materials. Inferior

materials applied well will give good service as long as

the materials resist weathering, but a roof Improperly

applied will give poor service from the beginning.

Some of the most common application faults are;

Built-Up Roofs

Failure to apply a layer of building paper over wood

decks or other decks with open joints (Figure 2-).

Failure to aover knot holes and cracks in wood decks

with metal.

Applying built-up roofs in cold or wet weather.

Inadequate nailing of felts in built-up roofs, resulting in the blowing-off and slipping qf felts on

steeper slopes.

*Illustrations are grouped at the end of this report.
- 5 -

Inadequate mopping s of hot bitumen between the plies of

felt. -Inadequate application (mopping instead of pouncing) of

hot bitumen in the cgnstruction of slag or gravel surfaced

roofs.

Too heavy application of asphalt on the weather surface

of smooth-surfaced built-up roofs. See Figure 3° -

Failure to broom felts smoothly behind the mop, resultr

ing in poor adhesion, wrinkles and buckles. See Figure h.

Asphalt Roll Roofings

Failure to cement the seams of roll roofings or to use

the proper kind of cement.

Applying roll roofings with exposed nails. See Figure

5o

Nailing roll roofing too close to the edge of the sheet

See Figure 6.

Failure to cut roll roofing into short (12-18 ft.)

lengths and failure to permit it to lie flat to lose the

"roll".

Failure to cover resinous knots, knot-holes, or wide

cracks in the roof deck with sheet metal.

Failure to use metal drip edge at eaves and rake.

Asphalt Shingle Roofs

Nailing asphalt shingles too high. Figure 7»

Failure to cement down the tabs of asphalt shingles

with quick-drying cement in windy areas.

Failure to use metal drip edge at eaves and rake.
Failure to use roll roofing underlay over eaves in

areas subject to freezing and thawing »

Metal Roofs

Failure to provide adequate side and end laps with

corrugated sheet roofingSe

Failure to paint tin (terne) roofing,,

Failure to provide adequately for expansion and aontraction with changes ...in temperature

Failure to fasten sheets adequatelyo

Rigid Roofing Materials (Slate Asbestos-Cement - Tile)

Nailing too tightly.

Using Improper rtailSo

3o 6 Use of Improper Materials

Practically all roofing materials are best suited for a

particular type of service and some are definitely unsuited

to certain conditions . It is obvious that shingle- type

materials serve best on the steeper slopes and that the lower

pitched roofs require roofing that will provide a^ continuous

sheet over the entire area.

Shingle-type roofs (asphalt, asbestos-cement, slate,

wood) may be used safely on slopes of five inches or more

per foot. On slopes lower than five inches, special pre--

cautions must be taken.

Asphalt roll roofings, including wide-selvage roofing,

may be used on slopes of two inches or more per foot. They

should not be used on flatter slopes-, not because it is impossible to construct a leakproof roof with them, but because

they do not resist weathering well where the roof drainage

is poor. Figure 8.
- 7

-

Built-up roofs are best suited to roof decks that

range from f^at to two inches per foot, though they may be

used on steeper slopes*

Metal roofs in sheet form and corrugated asbestos-cement

roofs should not be used on slopes lower than tl^iree inches

per foot.- These include special shapes of galvanized and

aluminum sheets, protected metal sheets and all batten

and standing seam metal roofings*

Soldered seam metal roofs (copper, terne) may be used

on flat or nearly flat decks*

3 e 7 Wind Damage

All roofings ara subject to damage from gtrong yi^ds,

and roofs, generally, are not designed \p withstand winds

of hurricane intensity* However the greatest damage to

roofs is not from hurricanes but, rather, from winds of

moderate intensity and the gusts that may reach 70 to 77

miles per hour that accompany them*

Asphalt roofings, particularly free-tab asphalt shingles,

improperly applied are probably most susceptible to wind

damage* Figure 9= illustrates the effect of a gust of wind on

such shingles that were nailed too high* Continued flexing

of these shingles weakens them and after a number of gusts

the shingle tab is blown off* The same is true if these

shingles are nailed correctly, but the free tabs are not

cemented down and accounts for the many cases where only

the exposed tab of a shingle is blown loose* Conventional

210-pound shingles nailed- correctly , but not cemented down,

have been shown to resist less than 100 gusts in a simulated

test. In a similar test with the shingle tabs cemented

down -they have resisted more than AOOO gusts*

Figure 10 shows another common cause of wind damage

to roofs, that is, the partial vacuum caused by wind blowing perpendicularly over the ridge of a roof and causing

the roll roofing to tug at its fastenings. This same

effect is apparent when wind blows against the side of a

building with a flat roof and is one of the most important
- 8 -

reasons for the adequate fastening of built-up roofing

feltSo In the case of built-up roofs it is the constant

pull from relatively mild winds that loosen the nails and

make the roof susceptible to the first strong wind to

which it is subjected

3=8 Exposed Nails

The tendency of exposed (uncovered) nails to work loose

has probably caused most trouble with ^sphalt roll roofings

since a large proportion of these roofings are applied with

the nails exposed* See Figure However, exposed nails

are always a potential source of trouble with roofing of

any type* Nails used to hold down curled wood -shingles invariably come loose as do nails in the battens used to

deflect water,_ over entrances to buildings*

3*^ Failure of Flashings

Flashings should be designed to furnish at least as

long service as the roofing* Many early roof failures are

actually flashing failures* -This is true particularly of

built-up roof's on flat or nearly flat decks* Numerous

cases have been observed where reroofing has been requested

when repair of the flashings or provision for new flashings

was all that was required to :make the roof leakproof* See

Figure 11*

When it- is considered that the function of flashings

is to provide a waterproof junction between the roof and

other parts of the structure and between roof sections,

their importance, ahd the importance of maintaining them

properly cannot be over-emphasized*

4* TYPES OF ROOFING

4*1 Built-Up Roofing

Federal and other specifications for materials used in

built-up roofs are listed on page^^ *
~ 9

-

^,1»1 Description and General Discussion

Built-up roofing is- exactly what the name implies, a

membrane built-up on the job from alternate layers of

bituminous- saturated felt and bitumeno- Since each roof is

custom-made, the importance of good workmanship cannot be

over-emphasized* Figure 12 Illustrates extremely poor

workmanship on both roof membrane and flashings*

The bitumen used to saturate the felt and as a plying cement and coating for the saturated felts may be

asphalt or coal-tar-pitch. These can usually be distinguished by their odors. Asphalt has a distinctly

oily odor and coal-tar-pitch a somewhat pungent, phenolic

odor, - These odors can be determined best with freshly

broken specimens or from the fumes of specimens that

have been ignited and freshly extinguished.

Coal-tar pitch is particularly adaptable for use

in the construction of the so-call-ed "dead-level" builtup roofs on which water collects and stands. Coal-tarpitch is more susceptible than asphalt to changes in

temperature, that is, roofing grade coal-tar pitch is

more fluid at high temperatures and more brittle at low

temperatures than comparable roofing grade asphalt-. Consequently, asphalt is better_.suited than, coal-tar pitch

for built-up roofing on steeper slopes.

The layers of felt in a built-up roof function

primarily to hold the layers of bitumen in place. They

do not materially c^ontribute to the waterproofness of

the roof and are not suitable for prolonged exposure to

the weather. Built-up roofs are always designated by

the number of plies they contain, for example, 3~ply and

5-ply roofs contain 3 and 5 p.lies of felt, respectively.

Coal-tar-pitch built-up roofs are always hot-applied.

The pitch is melted to a heavy liquid consistency and,

except when the felts are laid mechanically, Figure 13,

is mopped when used a^ a cement and poured when used as

a surface coating. Because of the susceptibility of coaltar pitch to changes in temperature, coal-tar-pitch roofs

should always be surfaced with slag, gravel, crushed stone,

promenade tile laid in a cement grout, or similar material.
- 10

Asphalt built-up roofs may be either hot- or coldapplied and may be either surfaced or unsurfaced o Hotappliad asphalt and coal-tar-pitch roofs are applied

similarly. Hot-applied asphalt roofs xise uncoated,

saturated felts; cold-applied roofs use saturated and

coated felts- and cut-back cements containing a volatile

solvent. Some cold-applied roofs are surfaced with emulsified asphalt.

Surfacing materials for built-up roofs serve three

important functions. , They permit the use of thick surface

coatings of bitumen, protect the bitumen from sunlight and

heat, and increases the fire resistance of the roofing.

The statement heard so frequently that "surfaced roofs are

undesirable because it is so difficult to locate the source

of a leak on a surfaced roof" is entirely fallacious. A

surfaced roof, constructed properly with a thick top pouring of bitumen, will not leak. Built-up roofs, except

those surfaced with promenade tile or similar surfacing

are not intended to carry much foot 'traffic. Tile surfacing or wooden walkways should be used on roofs that

are subjected to regular traffic.

Built-up roofs are adapted particularly to relatively

flat slopes (two inches ajid less per fjoot) because they

furnish a continuous membrane. They may be applied on

slopes steeper than two inches per foot when proper precautions are taken.

Built-up roofs are applied to a variety of deck materials, including wood, concrete, steel and gypsum, with or

without insulation.

Built-up roofs suffer by being designated as 10- , 15- or 20-year roofs., Too often these designations are interpreted to mean that the roof will require no maintenance

or repair for the stated period. Roofs that are not maintained or repaired will, in all probability, require replacement at the end of the stated period, while those^ that are

maintained properly can be expected to serve well beyond

the period.
- 11 -

4.1o 2 Roof Decks for Built-Up Roofs

Wood Decks

Should be tongued and grooved or splined.

Should be dry when roofing is applied

At least two nails per., 6 ino width at each rafter ,- nails driven flush*

Roof deck must be smooth - no irregularities*

Knot holes and cracks widen than 1/4 inch between

boards must be covered with sheet metal*

Poured- Concrete and Gypsum Decks

Deck must be dry, smooth, free from fnost or freezing

effects, properly graded to drains and free from loose

material*

If deck is uneven, high spots must be removed or low

spots filled with Portland cement or gypsum mortar.

Nailing strips in concrete-, when required, must be

treated to resist rot, must be properly keyed into the

concrete and must be flush with the surface.

Precast Concrete Units

Deck must be dry, smooth, free from frost or. freezing

effects*

Use cement mortar to level inequalities and fill cracks

in the deck*

Precast Gypsum Units

Protect units stored on the job from rain or snow*

Store metal-edge gypsum plank on edge, not more than

three tiers high, with ample ventilation*
- 12 -

Permit only that amount of gypsum decking to be applied

each day that can be covered vi^h roofing that day,.

Use only gypsum mortar to fill cracks and level inequalities in the rod decko

Steel Decks

Deck must be dry, firm, tight, free from rust, grease

or any loose material.. All steel decks should be shop

coated or paintedo

A«1«3 Storage and Handling of Materials

Felts

Felts, stored on the job must be protected from the

weather o It must be realized that these f elts though

they are described as ’’saturated" with asphalt or coal-tar

pitch, will still absorb considerable moigture if exposed

to ito Felts that contain moisture are certain to result

in blistered built-up roofs* Felt rolls should be stood

on end, not in contact with tfie ground*

When felts are applied, they should preferably be

rolled into the hot asphalt gr coal-tar pitch that has

been applied with a mop not more than three feet ahead qf

the roll* Sufficient asphalt or pitch should be present''

between the plies of felt to insure that, in no case, is

felt touching felt*

Immediately after the felt is rolled into the hot

bitumen, it should be "broomed in" with a stiff bristle

broom (Figure 13 ) o Any small blisters or buckles remaining should be slit with a knife and smoothed out with

the broom* If blisters or buckles larger than 8 in* in

any dimension are present, the felt should be removed and

re-laid * Asphalt and Coal-Tar Pitch

Drums of asphalt and coal-tar pitch should be stood

on end and protected from the weather during storage*
- 13

Asphalt^ and pitch should be broken up before placing

in the kettle. For safety, pieces should be slipped ' father

than dropped into mel'ted bitumen. _ The inspector qhould insist that .the temperature of

the melted bitumen be controlled with a thermometer.

Both agpt^alt apd coal-tar pitch are hardened and- embrittled

by overheating and, consequently, are rendered more susceptible i^o changes- in temperature. Overheating the bitumen

may therefore reduce the useful life of a built-up roof.

Modern heating kettles are usually equipped with thermometer, but these are frequently broken or so covered

with bitumen as to be illegible. ..,The inspector should

be provided with a thermometer, two types, of which are

available.

Asphalt should not be heated above h2'^°F and should

normally be not lower than 350°F when poured or mopped

on a roof. If asphalt with a- softening point cqf 150°F or

lover is used, \he maximum kettle -temperature is 375°F

and the minimum temperature for ap^ication 300°F,

Coal-tar pitch should not be heated above ^00°F and

should not. be poured or mopped at temperatures under

350°F. Dense yellow fumes from the heating kettle is

proof that the coal-tar pitch is too hot.

The final coating of asphalt or coal-tar pitch on

mineral-surfaced built-up roofs should always be poured

rather than mopped to insure sufficient bitumen for embedding the surfacing. Figure iV.

To determine whether .mineral surfacing is embedded

properly, the inspector should include a broom as part

of his regular equipment. Figure 1^.

Surfacing Materials

Surfacing materials for built-up roofs should be

dry and free from dust since wet or dusty surfacing materials will not bond well with the bitumen. _ If wet, they

should be dried by piling over a heated metal drum with
- l4 -

open ends* If roofing work must be done in cold weather,

this method may be used to heat the surfacing material

to secure proper embedment * If crushed stone is used

for surfacing, the stone should not have sharp edges*

Insulation

Since the applic.ation of insulation varies with the

different types of decks, the kinds of insulation and the

use of the structure* no attempt is made to give detailed

instructions here* The inspector should see that insulation is stored under cover and that it is installed strictly

according to the standard specifications for new roof construction, with no more installed on a single day than can

be covered with roofing on that day* If light-weight

concrete is used as an insulating material, it must be

dry before the roof membrane is applied*

All decks over which insulation is to be applied must

be provided with wood edge strips at least ^ inches wide

and of the same thickness as the insulation at all open

edges and at walls or curbs if metal base flashings are

to be installed*

On non-combustible decks with inclines that require

the nailing of felts, wood nailing strips of the same

thickness as the insulation must be provided* Steel

decks must be provided with a layer of insulation to

serve as a base for the built-up roofing*

A vapor barrier must be provided under insulation

to prevent the absorption of moisture by the insulation

from the under side* This vapor barrier must be continuous to be effective* Two layers of 15-pound, asphaltsaturated felt mopped solidly between with asphalt or one

layer of double-coated felt with edges sealed provide an

adequate vapor barrier* Other types of vapor barriers are

available * h*l*^ Determining Treatment for Built-Up Roofs

From the data furnished in the historical record and

that listed on the inspection form must come the determination concerning what treatment, if any, the roof shall
- 15 -

receive. No matter how detailed these data may be, it

is usually necessary to exercise some judgment a-f^ter considering a number of pertinent factors.

The kind of structure, whether permanent or temporary, its occupancy; the kind of roof, its age, and

whether or not leaks occur, are among the most Important

considerations in determining the treatment,

A roof on a structure designated for temporary occupancy should be given only the minimum maintenance or repair necessary to keep it leakproof during the period of

occupancy, A roof on a structure for permanent occupancy

should be considered in the light of the prolonged use of

the structure and should be given the best maintenance,

repair or reroofing possible,

4,1.5 Maintenance Methods - Built-Up Roofs

(Treatment Prior to Failure)

Note % Asphalt and asphalt- saturated felt should always be used in the maintenance of mineral- surfaced

,

asphalt built-up roofs; coal-tar pitch and coal-tar saturated felt in the maintenance of coal-tar pitch, builtup roofs. Asphalt and coal-tar pitch are not compatible

so that contact between the two should be avoided whenever possible. In the text that follows, the terms

"bitumen” and "bituminous" are used to indicate asphalt

when mineral- surf aced asphalt T’oof maintenance is discussed and coal-tar pitch when coal-tar pitch roofs are

discussed

,
- 16 -

A« Mineral-Surfaced, Built-Up Roofs

(1) Bare Areas (Small Areas)

(a) Bituminous Coating Exposed (Figure l6.)

Treatment ; Brush loose gravel or slag from bare area^

Cover the bare area with hot bitumen poured on at a rate

of 70 pounds per square and embed fresh gravel or slago

Old gravel or slag may be reapplied if dirt and dust are

screened from ito Do not attempt to apply hot bitumen

over slag or gravel surfacing since it will not adhere

(Figure 17»

)

(b) Felts Exposed

Treatment ; If exposed felts appear to be weathered,

Figure^ iB, brush all dust and dirt from the exposed area

and, in the case of asphalt roofs, apply one thin coat

of asphalt primer meeting Federal Specification SS-A- 7OI 0 When primer is dry, treat as described fgr bare areas

with the coating exposed o Coal-tar pitch roofs are

treated similarly except that no primer is required before

the coal-tar pitch is applied

o

(2) Small Blisters and Buckles*

Treatment % If bare, treat small blisters and buckles

as bare areas; otherwise disregard them. (Figure l*9o)

(3) Bituminous Coating Weathered Severely Over Entire

Roof Area (Figure 20o)

Treatment ; Remove bituminous coating and mineral surfacingo Removal is accomplished best in cool weather

When large roof areas are involved, the use of mechanical

equipment to remove the bituminous coating and surfacing

material is more economical than removal by hand methodSo

Repair disintegrated felts, damaged areas:^^ blisters and
- 17 -

buckles as described under "Repair Methods, Mineral-Surfaced,

Built-Up Roofs"* Sweep off loose material* Recoat with hot

bitumen poured on at a rate of 70 pounds per square and into

the hot bitumen embed 4-00 pounds of gravel or 300 pounds of

slag.

B. Smooth-Surfaced, Asphalt, Built-Up Roofs

(1) Organic (Rag) Felt Roofs

(a) Felts Exposed (Small A.reas)

Treatment : Same as for mineral- surfaced , built-up

roofs, except that 20-25 lb* asphalt should be mopped

per square and the mineral surfacing omitted.

(b) Small Blisters and Buckles

Treatment ; If felts are exposed, treat as described

for exposed felts, mineral- surfaced , built-up roofs, applying 25 lb, asphalt per square and omitting mineral surfacing.

If felts are not exposed, disregard small blisters and

buckles,

(c) Asphalt Coating Weathered Severely Over

Entire Roof Area

General Discussion : Smooth-surf aced , asphalt, built- " up roofs, in which the surface mopping is relatively thin

and is exposed directly to the weather, usually show definite alligator ing of the surface coating within 3 to 5

years. Alligatoring is always most severe where the

asphalt coating is thickest If allowed to proceed,

alligatoring will develop into cracking (Figure 21).

Once the surface coating is cracked, water enters the

membrane, leaks may appear and the roof^ deteriorates at

a rapid rate. Consequently, maintenance before cracks

appear is necessary.

The kind of maintenance selected should depend on

the future use of the structure, as indicated below.
- 18 -

c-1. Maintenance For An Expected Use of the Building

of Not More Than Four Years

Treatment s Remove all loose dust and dirt by sweeping,

vacuuming or air blast* Apply one coat of asphalt primer

meeting Federal Specification SS-A-701* A thin coat only

is desired, applied preferably by brushing, to avoid excess

primer* After primer is dry, apply one pf the following;

(1) Asphalt emulsion meeting Military Specification MlL-R-3^72, "Roof Coating; Asphalt Base

Emulsion", by brush or spray, at aerate of 3

gallons per square*

p

(2) Asphalt-base roof coating meeting Federal

Specification SS-R-h^l, "Roof Coating; Asphalt,

Brushing-Consistency" , amended to contain from

8 to 20 percent mineral filler instead of 5 to

25 percent, by brush or spray, at a rate of 3

gallons per square* While., many good proprietary roof coatings are available, they usually

cost several times as much ap coatings purchased

under Federal Specification ^S-R-h5lo They may

be "guaranteed" for periods up to 10 years or

longer, but the guarantees usually provide only

for furnishing additional coating if failure

occurs* In the absence of any fool-proof test

to determine the quality of roof coatings, material purchased under the Federal Specification

is adequate for maintaining roofs in this category for an expected use of not more than 4

years*

(3) Fatty-acid-pitch base roof coating meeting

Interim Federal Specification SS-C-00560,

"Coating Material; Fatty-Acid-Pitch Base,

Non-Bleeding, Brushing and Spraying Consistency, Foundations, Roofs, Walls, etc*", at a

rate of approximately 3 gallons per square* -
- 19 -

(^-) Hot-mopping asphalt meeting Federal-Specification SS-A-666, "Asphalt- for Built-Up

Roofing, Waterproofing and Dampproofing",

of the same type as used in the original construction, at a rate of 20 to 25 Iho per

square c’

If the a.sphalt coating is alligatored but not

cracked and the felts are not exposed, the

primer may be omitted with the asphalt- and

f atty-acld-pitch base coatlngs» If an emulsion coating is to be applied to such surfaces, dust apid dirt may be washed off "with

a ^tream of water from a hosOo The emulsion

may be applied to a damp, but not a wet surff.ce

,

The above methods are limited to use on smooth-surf aced

,

organic-felt roofs of relatively short expected use because

of the tendency to alligator and eventually crack of any

coating material t^hat is applied over an alligatored or

cracked q^sphalt coating (Figure 22) » This tendency increases as the coating thickness is built-up

c-2.j^ Maintenance for Prolonged Use

Treatment ; Clean off all loose dirt or dust by sweeping, vacuuming or air blasts Apply one coat of asphalt

primer meeting Federal .^Specification SS-A-701, applied

preferably by brushing, avoiding excess primer o After

primer is dry, apply asphalt emulsion meeting Military

Specification MIL-R-35-72* except that it need not contain asbestos fibers, at a-rate of 2 gallons per 'square.

Immediately after applying the emulsion, while it is

still wet, embed strips of fibrous glass mesh, either

woven or non-woven, in the emulsion, lapping the strips

two inches and using a moistened brush to force the mesh

into the emulsion,

*Clay-type emulsion should be used with the glass membrane.
- 20

Over the fibrous glass strips, while the first coat of

the emulsion is still wet, apply a second coat of emulsion

at a rate of 1 gallon per square o Brush this second coat

into the mesh with a fiber brush. Allow this pecond coat

of emulsion to set firmly, (At least 12 hours 'in good

drying weather, longer in damp, humid weather.)

Apply a final coat of emulsion at- a rate of 2 gallons

per square. Fibrated emulsion may be used for the final

coat, but its use is not essential.

If the asphalt surface, is alligatored but not cracked

and felts not exposed, treat as described in the previous

section, omitting the asphalt primer.

Figure 53 illustrates the benefit obtained by the

use of the fibrous glass strips. The section on the

left shows an area of an alligatored roof that was

simply coated with asphalt emulsion. The section on the

right was coated with the same emulsion reinforced with

glass. Both were exposed ^-1/2 years.

This method of treatment is described in detail because it has been used with satisfactory results and it

is believed that it provides adequate safeguards against

poor workmanship. Variations of this method, in which

the glass strips are embedded in a coating of emulsion

and a finish coating of emulsion applied, and in which

different quantities of emulsion are used, have also

given patisfactory results... With any method, workmanship is as important as materials and a satisfactory -job

will result if the emulsion costings are fused into a

tightly adherent membrane, reinforced "with the glass

fibers.
- 21 -

(2) Asbestos-Felt Roofs

(a) Felts Exposed (Small-' Areas)

a-lo Maintenance for An Expected Use of the Building

of Not More Than Four Years

General Discussion ; Smooth-surf aced ^ asbestos-fbit

,

built-up roofs may be surfaced originally with hot asphalt

or with a cold-applied asphalt-base coatingo After four

or five years of exposure (sometimes earlier with the coldapplied coatings), light-gray or even white areas appear,

indicating that the felts are partly exposed (Figure 2h)^

Since the asbestos felts are constructed mainly of inorganic materials, exposure to the weather is much less

serious than with organic feltSo

Treatment i For an expected use of not more than h

years, no treatment is necessary« Disregard small blisters and buckles.

a-2. Maintenance for An Expected Indefinite Use

Treatment ; Manufacturers of asbestos felts generally

do not recommend recoating asbestos felt roofs at any

time. However, recoating with asphalt emulsion meeting

Military Specification MIL-R-3^72 at a ra|:e of 3 gallons

per square, at intervals of four or five years, will

prolong their usefulness indef Initely . To be most

effective for long periods of maintenance, the initial

coating should preferably be an asphalt emulsion of

thin asphalt cut-back rather than a hot-applied or conventional asphalt fibrous roof coating.

The use of fibrous glass mesh is not recommended

in the maintenance of asbestos-felt roofs.
22

(3) Cold-Process Roofs (Roofs 9 onstructed with coated

organic felts cemented to each oth.er and to the

roof deck with a special quick- setting cement as

recommended by the manufacturer of the felts and

surfaced with asphalt emulsion or with a coldapplied coating recommended by the manufacturer*)

(a) Felts Exposed

Treatments Recoat with asphalt emulsion meeting Military

Specification MIL-R-34-72 at a rate of 3 gallons per square,

or with the material with which they were coated originally.

Disregard small blisters or buckles*- Large blisters or

buckles shall be treated as^ described under Repair Methods.

*+.1.6 Repair Methods - Built-Up Roofs

(Treatment following at least

partial failure)

A. Mineral-Surfaced, Built-Up Roofs

See note under 4,1.5 Ma.intenance Methods - Built-Up

Roof s

,

(1) Felts Exposed and Partially Disintegrated (Small

Areas) - Figure 25.

Treatment ; Scrape off all surfacing material to a distance at least 2-1/2 feet beyond the §:rea of disintegrated felts. RemCve disintegrated felt layers and replace them with new l5-pound bituminous-saturated felts

of approximately the same size and mopped in place with

hot bitumen. Apply at least two additional layers of

15 -pound saturated felt, mopped on with hot bitumen and

extending at least 12 inches beyond the area covered by

the replacement felts. Apply pouring of hot bitumen

to the repaired area at a rate of 70 pounds per square

and into it, while hot, embed fresh gravel or slag. Old

gravel or slag may be reapplied if dirt and dust are

screened from it.
- 23 -

(2) Roof Membrane Cracked

Treatment s Treat a_s described for disintegrated

felts, except that it is usually only necessary to mop on

at least two plies of l5-pound saturated felt, followed

by the heavy pouring of bitumen, ' with slag or gravel surfacing,,

(3) Large Blisters or Buckles That Have Cracked to

Allow Water to Penetrate o (Blisters or buckles,

though large, if intact, will not leako Only

if the felts disintegrate ar are cracked should

they be repairedo) -JEigure 26 o Treatment s Scrape off all surfacing material to a

dry felt surface at least 2-1/2 feet beyond the edge of

the blister or buckle o Make two cuts a-t right angles to

each other extending 12 inches beyond the edge of the

blister or buckle. Fold back the four sprners of the

membrane and allow to stand until thoroughly dry. When

dry, apply a^ liberal mopp-ing of hot bitumen, fold down

‘ the four corners or the membrane and press them firmly

into the hot bitumen. Apply at least two additional

layers ofl^-pound saturated felt mopped on with hot

bitumen and extending at feast 18 inches , beyond the ends

of the cuts. Apply a pouring ''of hot bitumen at a rate

of 70 pounds per square and while hot, embed gravel or

slag,

(4) Fishmouths or Buckled Open End Laps,

Treatments Scrape off all surf acing 'material to a

distance ^t least 12 inches beyond the affected apea.

Cut the fishmouth or buckled end lap and cement down the

loose felts with hot bitumen, ' Apply alt least two layers

of 15-pound saturated felt mopped vOn with hot bitumen

and extending at least 8 inches beyond the end of the

cut felt and 8 inches below the lap edge. Apply a

heavy pouring of hot bitumen and into it, while hot,

embed gravel or slag.
2h -

(5) Felts Exposed and Disintegrated in Numerous

Areas, Figure 27,

General Discussion ; Under this category no definite

criteria can be established to determine whether the existing membrane should be repaired by adding plies of felt or

whether the old membrane should be removed entirely and a

new one applied.

The condition of the membrane should largely govern,

but the historical record of the raof will he of definite

assistance in making a decision.

(a) Cases Where Repairs are Indicated

Roof has not reached its expected life; that is, roughly,

for a 5-ply roof, 20 years; a, ^-ply roof. Ip to 20 years;

and a 3-ply roof, 10 years.

Base felts are in ^ound condition and ijre not waterlogged.

Insulation, if present, is dry..

Leaks that have developed are few in number and are

not serious.

(b) Gases Where Reroofing Is Mandatory?

Roof has exceeded its expected life with little qr

no maintenance. ‘

''

Felts have disintegrated and disbonded and entire

membrane is waterlogged.

Insulation is wet and/or disintegrated.

Numerous leaks of a serious nature have developed

in the membrane.
. 25 -

(c) Repairing by Applying Additional Plies of Felt

One cardinal principle in applying additional plies

of felt to an existing built-up roof is that the additional

felts should never be mopped solidJ.y to an existing membrane, The repair membrane must be isolated from the old

membrape by a "dry" felt layer, spot or strip mopped, or

nailed, or l^y one-half inch of ro6f insulation strip

mopped, and if possible, nailed through the old membrane

,to the roof deck. If the slope of the roof is greater

than 1 inch per fnot , some provision must be made for

fastening the felts and the insulation. The use of insulation is desirable because it effectively isolates

the old membrane :from the new one and provides a smooth

surface free from irregularities for the new membrane.

Another principle, equally important, is -^lat the

new membrane should contain not less than three plies of

felt.

(d) Preparation of Surface to Receive New Membrane - All Types of Decks;

Remove mineral surfacing, bituminous coating and ^11

loose and disintegrated felts. (Refer t-o section on Maintenance of Mineral-Surfaced, Built-Up Roofs,)

Repair blisters, buckles, cracks and fishmouths as

indicated under "Repairs to Small Areas", omitting final

pouring of bitumen and mineral surfacing material.

If new flashings are to be installed, cut off existing membrane flush with the base of fire and parapet walls, ..

\ (e) Application of New Membrane to Existing Membrane on Insulated Concrete Decks;

e-1. Saturated Organic Felt with Insulation

Treatment ; Mop solidly with hot bitumen one-half inch

of roof insulation to the existing membrane. Follow with

at least 3 plies of 15-pound saturated felt mopped solidly
26 -

to the ii^sulation and to each other with hot bitnmen at

a rate of 25-30 pounds per square, followed with a pouring of hot bitumen at a rate of 70 pounds per square,

into which gravel or slag is embedded at a rpte of 4-00

pounds of gravel or 300 pounds of slag per square

o

e-2o Saturated Organic Felt Without Insulation

Treatment ; Spot or strip mop with hot biiumen one

ply of 15 -pound saturated felt to the existing membrane.

Follow with atq least 2 plies of l5-pound saturated felt

mopped solidly and finished as described in the preceding paragraph.

e-3o Asphalt and Asphalt-Saturated Asbestos Felt - With and Without Insulation

Treatment s Proceed as described for saturated organic felts using asphalt- saturated asbestos felts, except that the finish coat should consist of asphalt emulsion meeting Military Specification MIL-R-34-72, applied

at a rate of 3 gallons per square.

(f) Application of New Membrane to Existing

Membrane on Wood Decks

;

Treatment s- Proceed as described for concrete decks

except that insulation and felt should always be nailed

over wood decks in addition to the mopping recommended

when applying a new membrane over concrete,. Spot or

strip mopping may be omitted when the new membrane is

applied directly i^o the old, the first ply being simply

nailed

.

(g) Application of New Membrane to Existing

Membrqne on Gypsum Decks

s

Treatment s Treat as described for wood decks. If

the roof deck shows cracks on the under side, the use of

insulation under the new membrane is mandatory. '
27 -

(h) Application of New Membrane to Existing

Membrane Over an Insulated Roofs

Treatment s First make certain that the old insulation

is dry and not disintegrated » If the insulation is not

thoroughly dry or if it shows any evidence of disintegra-

„

tion, the existing roofing and insulation should be removed down to the roof deck and a new r-oof applied

If satisfied that the insulation is in good condition,

apply an additional layer of 1/2-inch Insulat-ion, f^ollowed

by 3^ layers of l5-pound saturated felt, mopped on and

finished as described for concrete deckSo

4<,1„7 Rerooflng

Reroofing, when necessary, should be accomplished in

accordance with standard specifications for new roof constructiono

Selection of a specification fop a new roof should be

made mainly on the basis of the expected future use of a

structure

Preparation of the deck for reroofing s Remove the

old membrane entirely.

Restore the deck to as nearly "new” condition as

possible.

On wood decks remove all rotted boards, replace with

sound boards and renall loose boards.

On cracked concrete or gypsum decks apply at least

1/2 inch of insulation before applying the new membrane.
28 -

4,1,8 Federal and Military Specifications Used

in Built-Up Roof Construction, Maintenance and Repair, (Military Specifications designated "MIL", all others are

Federal.

)

Title

Asphalt*, (for) Built-Up Roofing, Waterproofing and Dampproofing,

Types I and II, Roofing, Depending on

slope of roof.

Pitch; Coal-Tar (for) Mineral-Surfaced

Built-Up Roofing, Waterproofing and

Dampproofing.

Type I, Roofing,

Felt; Asphalt-Saturated (for) Flashings,

Roofing and Waterproofing,

Type I - l5-pound.

Type II - 30-pound.

Felt; Coal-Tar-Saturated (for) Roofing

and Waterproofing.

Type I - 15-pound.

Type II - 30-pound.

Felt; Asbestos, Asphalt-Saturated and

Asphalt , - Coated for Built-Up Roofing.

Class A, 20-pound (one side coated).

Class B, 50-pound (both sides coated).

Felt; Asbestos, Asphalt-Saturated, Uncoated,

for Flashings, Roofing & Waterproofing. ^ Type I, Perforated.

Class A, l5-pound.

Type II, Plain.

Class A, 15-pound.

Class B, 35-pound,

Designation

SS-A-666

R-P-381

HH-F -191

HH-F-201

HH-F -182

HH-F-185
„ 29 -

Title Designation

Asphalt Primer (for) Roofing and

Waterproofing* SS-A-701

Cement 5 Bituminous Plastic* SS-C-153

Type I - Asphalt Base*

Type II - Coal-Tar Base*

Roof Coating; Asphalt, Brushing-Consistency * SS-R-451

Roo'f Coating; Asphalt-Base Emulsion* MIL-R-3^72

Coating Material; Fatty-Acid-Pitch Base,

Non-Bleeding, Brush and Spray Consis- SS-C-00560

tency, for Foundations, Roofs, Walls, etc* (Interim)

Surfacing Materials for Built-Up Roofs* MIL-M-13^30

4*2 Asphalt-Shingle Roofing

Federal Specif icationss

SS-S-OO298 (Interim), Shingles; Asphalt, MineralSurfaced, Thick-Butt,

SS-S-OO3OO (Interim), Shingles; Asphalt, MineralSurfaced, Uniform Thickness,

Type I, 4- in. Exposure*

Type II, 9-in, Exposure*

4*2,1 Description and General Discussion

Note s For a more complete description of asphalt

shingles, including manufacturing methods and methods of

applida'tion, it is urged that one or both of the following

publications be obtained? National Bureau of Standards

Building Materials and Structures Report BMS-70, "AsphaltPrepared Roll Roofings and Shingles"* Copies available

from the Superintendent 'of Documents, Government Printing

Office, Washington 25, D* C» "Manufacture, Selection and
- 30 -

Application of Asphalt Roofing and Siding Products", pub

lished by the Asphalt Roofing Industry Bureau, 2 West

^5th Street, New York 36, N. Y. Available on request. to

the Asphalt Roofing Industry Bureau.

Asphalt- shingle roofing is manufactured in single

or multiple units of roofing felt saturated and coated

on both sides with asphalt and surfaced jcn the weather - side with mineral granules. The asphalt* coating may

or may not contain fine mineral stabilizer.

The surfacing materials on asphalt shingles serve

the same functions as those of built-up roofs and, in

addition, provide a choice of colors and color blends.

The surfacing materials (granules) are either natural

products such a^s slate or trap rock or other mineral

products with a ceramic coating. Resistance to light

transmission is an important requirement for roofing

granules to protect the asphalt coating from solar

radiation.

Asphalt shingles are available in a number of forms

or shapes, the most common being the square-butt, strip

type which, when laid, gives the effect of individual

shingles Laid by the American or wood- shingle method.

Other types are hexagonal strip, individual shingles

laid by the American, Dutch lap or hexagonal methods

and lock-down shingles of various types.

One of the most important considerations in the

selection of asphalt shingles is "coverage", the term

used to describe the number of layers of roofing furnished by a particular type of shingle in place. Single

coverage sjiingles provide but one layer of material over

a large proportion of the roof area; double-coverage

shingles provide two layers ov_er most of the roof area;

triple coverage, three layers, etc. The better the

coverage, other considerations being equal, the better

the service that may be expected.
- 31 -

Weight is another important c^onsidera-tion in the

selection of asphalt shingle s» Shingles should weigh at_

least 2^0 pounds per square (100 square feet) when ^ppliedo

Headlap is important in determining the waterproofness of shingles-o Various definitions for headlap have

been proposed, one of., the most realistic being the dis~

tance water. ..must travel upwarb from the outside to the

inside of a roof, assuming there are no breaks in" the

fabric o With square-butt strip shingles, headlap is the

distance a.=-shingle in any course overlg^ps a shingle in

the second course below it. With shingles laid by the

Dutch-lap method, it is the distance a shingle c^verlaps

one in the_^ next course below The greater the headlap,

the better the waterproofnesso

The exposure of a^^shingle is defined as the maximum

distance the shingle is exposed to the weather, disregarding the si^ace between individual shingles and the

cut-out sections of square-^tab strip shingleso Coverage,

headlap slid exposure §,re iriterdep^endent ; as the exposure

is increased, the headlap) and coverage are decreased cor-^

respondinglyLo As the exposure is increased, the possibility of wind damage is increased*

Asphalt shingles generally are eligible :^or the

Class C fire resistance rg,ting of the Underwriter's

Laboratories, Inc», which indicates that they are effective against light fije exposures. One proprietary stj’lp

shingle is currently available with a Class A fire resistance rating, indicating that it is effective -against

severe fire exposure. These- -shingles are herinafter

referred to as "Class A".

Shingles covering wide ranges of weight pnd coverage are available. However, the square-butt strip

shingle, 12 by 36 in. in size, with an exposure of

5 in, and weighing approximately 210 “lb. per square

applied, has come to ''be the generally accepted aspha,lt

shingle for roofs on structures with slopes of h in.

or more per foot. Subsequent sections will therefore

deal primarily with square-tab strip shingles, though
- 32 -

kinds of decks, methojds of handling and storage, weathering cjiaractqristics , ^nd methods of maintenancie, and re-1^

pair apply ^most equally to a^l types- of asphalt §hingres.

The characteristics of representative ^quare-ytab shingles

are shown in Table '].» ho2o2 Roof Decks for Asphalt-Shingle"Roof

s

Wood decks for asphalt- shingle roofs should be" of

well-seasoned sheathing lumber, nominal 1 in, thickness, not mcpe than 6 in, i;/ide, preferably tongued and

grooved, or of plywood, exterior grad,g, not less than

1/2 J.n, thick.

Sheathing board^s should- be fastened tc^ each r-after

with two nails to provide a-smootir, even surface. Any

knot |Toles, resinous areas or loose knot^s should be

covered with sheet metal.—-

The deck should be covered with l^-lb. asphaltsaturated felt prior to laying the shingles,

1,2,3 Storage and Handling of Asphalt^ Shingles

Asphalt shingles should be handled carefully at

all times to prevent damage, .Particular care should be

exercised during extremes of temperatures. When hqt

they may be torn rather easily and when cold, the ^sphalt

coating becomes brittle and may be- cracked if the shingle

is bent. Bundles should be lifted by placijig the hands

underneath, not by the wires or boards. They should not

be thrown or dropped ajid hooks should not be used.

Shingle bundles stored in warehouses or on the^ job

should not be piled so high that the bottom ^Shingles

will be damaged. Two- square bundles should be stored

not more than 5 bundles deep and three-^ square bundles

not more than 8 bundles deep. In any base, stacks of

shingles should not be more than 3-1/2 ft. high. They

should not be stacked directly on the floor of a warehouse or on the ground. They should be stacked on

planks spaced so that the shingles do not sag.
TABLE

1.

SQUARE-TAB

STRIP

SHINGLES

33

o w

0) iH Ph cd O o O o 0 -H CD ^3 00 CO O oo O cd ft cr* S S CO J"

ft bO

0 5=! CD •H P Ph . a ft CD CdCAJ J" J"

-P O ft P -P m on on a o o' ft

==4 pa, CO

C\J C\J CM CM

CDCD 0

ft ft p O tuO p cd o o o o s:! 0 P 00 00 o 00

o ft ft CT* 1—1 Ox! CO S CO

per re

led

o o O o o Cu rH rQ i—

1—1 Icn

« C3 ftft C\J CM c(l CM -P o' ft

:s CO <5

rHft CJN CON !>- C7n

1 on on on '^oO

ON 0 >5 bOft

0 ft ON <0N O C5N P 1 0 CM >O

O !>s

ITN un iTN iTN

rH / ft CM CM on CM rH

I TD ft a

cd Cti <Zl CD I—I *HC\J C\J c(l C\J

0 0 O ft P iTN UN IP\

M P •H

pq 0

NO NO NO NO

0

CO

o

(—

on on on on

•H •H X! X! X X CO

CM CM o CM

1—

ft 1—

ft

P>

-P 0 0

1 P P a 0 a w

bO O X! P 0 P 0 X •H "H 1 O P e p >

0 -p ft .3 ft X 0

0 0 o ft o ft o 0 Q P •H p ft P ft IP

1=3 x! 1=3 x! ft ft ft
- 3 ^ -

Asphalt shingles stored on the job must be proteobed

from the weather. If water comes in contact with the

non-weather surface of the shingles, the thin asphalts

costing on that surface may 'permit some w^er to be

absorbed by "the felt base and blistered shingles will

result. Contact with oils "or solvents must be avQlded,

Determining Treatment for Asphalt-Shingle Roofs

As-phalt- shingle roofs that are applied properly

usually require no special maintenance gr repair treat-.^

ments. Shingles normally last for a number of years

with very little change in appearance. The first indicatioh of normal weatheringj^is the loss of mineral surfacing granules, slight qt first, but ^ccelerqting as the

loss of granules exposes more of the asphalt coating“'to

the weather. Figure 28.

No definite periods can be ascribed for the various

phases of weathering because tjiey will vary with the

direction of exposure, the climate and the slope of the

roof. Weathering is more rapid in hot, humid climates;

on southern and western" exposures and on ^ow-pitched

roofs, Figure 29.

Asphalt- shingle roofs with at least dopble coverage will usually not leak, eyen if most of the granular

surfacing has disappeared . _ However, without the surfacing, weathering proceeds rapidly, the shingles become

brittle and more vulnerable to wind damage, ao that

large bare areas are an indication thai: the roof will

soon need attention. Figure 30,

The recoating of weathered a-sphalt shingles is

not recommended- for the following reasons. Shingles

that have weathered to the stage that recoating would

seem to be Indicated are probably so brittle that they

are likely to be damaged severely by the recoating

operation. Figure 31. Further, the unequal weathering

of the exposed tabs will result in an unaqual absorption of the coating material, thereby causing the
- 35

coated tabs to curl unless great care is taken to cement

tightly all three edges of all exposed tabs* This comi:

plete cementing is also important in that if it is not

done, oj:herwise entraj>ped water may back up above the

top of the shingle and c^use leaks. Finally, experience

has shown also that the cost of recoating and sealing

the edges of the shingle tabs in most cases approaches

so nearly that of rerooflng that reroofing is the more

economical procedure.

In asphalt-shingle ropfs no such sharp distinction

can be drawn between maintenance and repair work as was

possible in the case of built-up roofs. Maintenance

and i^epair methods for asphalt- shihgle“ roof-s are therefore combined. They will be confined to correcting

those defects J.n application that are susceptible to

correction.

4.2.5 Maintenance and Repair Methods

Asphalt-Shingle Roofs

A. Maintaining Roofs Having Improperly Nailed Shingles.

The defect that is found most fij^equently in the

app![.ication of square-tab strip shingles is the improper^

.placement qf nailg, tfiat is, ng.iling too near the top

of t.he shingle rather than 1/2 to 3/4 in. above a line

drawn through the top of the cut-out portions. Figure

32, Bec^ause of the reduced thickness of the upper

part of thick- butt shingles, shingles of this type are

affected more than uniform thickness shinglgs by too

high nailing.

Top-high nailing of shingle-s, should be corrected

by placing a spot of quick- setting asphalt plastic - cement under the center of each tab^and pressing the

tab down firmly. The spot of cement should be approximately 1-1/2 in. in diameter when pressed flat.

Figure 33 • Special quick-setting cements are obtainable from most manufacturers of asphalt roofing

products. Approximately 1/3, gallpng^of cement is
- 36 »

required per square of shingle So The shingle tabs should

not be bent up farther than necessary to place the

cement. No attempt should be made to renail shingles

in the proper locations since :^he bending required may

damage the shingle tabs.

B. Maintaining Asphalt-Shingle Roofs in Areas^of Strong

Wind s

.

The cement l^ireatment described above should -also

be used to preveiit wind damage to shingles th^t are

nailed correctly but are located in areas where fe-trong

winds are prevalent.

C. Maintaining Asphalt-^Shingle Roofs Damaged hy Hail..

Severe hail storms ma^ damage ^sphalt- shingle roofs

beyond repair, particularly if the shingles have been

exposed for a number of years. See Figure With

such damage, both layers, of shingles are broken, the

roof will leak severely and rerooflng is mandatory.

Severe damage such as shown in Figure 36? where

the asphalt coating and surfacing g:^anules have been

removed from numerous small areas, but where the

shingles are not broken, will not cause |:he r.pof to

leak. However, the life of a roof so damaged will be

shortened materially. Maintenance is not practicable

since the cost would probably equal that of a new

roof.

Minor hail dama^^e, where only occasional areas

from which the coating and surfacing granules have

been loosened may be repaired by covering the bare

areas with asphaltn.base rj^of coating or plastic

cement, asphalt emulsion, or cotton- seed-pitch base

roof coating. (See Section ^.1. 5-B. (l)-o-l. .f or

description.

)
” 37 "

Do Renewing Rotted Eaves Bo0.rds®

The roof sheathing boards at the gaves are frequently

rotted befdre bhe roof shows any signs pf deteriorationj

because of failure to provide a^proper drip edgeo In

such cases the first three or four courses of shingles

should be removed 5 new shealihing applied 5 together with

a metkl drip edgee New asphalt shingles should-then be

applied, taking particular care not to damage the old

shingles when removing nails to join the new roof section

with the old one^

Eo Installing Drip Edge at RakSo

Gases where shingles have been applied without a

proper overhang of 1/4 to 3/8 ino at 'the rake and whehe

no metai drip ed^^ has been applied may be 'eorrected

,

before the. roof sheathing has deteriorated, by removing carefully any nails holding the shingles at the

rake and applying a metal drip edge.o The shingles

should then be renailed and al!}. (pf the shingle tabs

adjoining the rake cemented as 'described in

4o2o 6 Reroofing with Asphalt Shingles

Asphalt shingles may be used for reroofing over

wood- and asphalt-- shingle roofs and over smooth-' and

mineral^- surfaced asphalt roll roofingo However, the

better practice is'' to remove the existing roof covering » Among the reasons for removal ares An opportunity is given to correct, deficiencies in the roof

deck, such as warped o^r rotted framing and sheat|hlng 5 better nailing is provide'd^ shingles applied on 'a

smooth surface render better ^ervice than on an uneven

surface I molsl:ure in the old roofing mg.y enter the

new shingles„and cause blisters, and the appearance

of the reroofing job is better
38

In cases^ where asphalt shingles have been applied

over an existing rgof, and reroofing is necessary, the

two roofs should be removed ^i'^hout question<> The reasons

for removal given in the preceding paragraph apply with even

greater force in guch cases

»

L No attempt should be made to apply asphalt- shingle

roofing over existing metal, slate or asbestos-cementroofs because of difficulties i^ najJ.lngo

A. Preparing Deck for Reropfing with Asphalh Shingles*

(1) When Existing Roofing Is Removed^rRestore the roof deck to as nearly "new" condition

as possible, as follows

s

Remove all protruding nails and renail sound

sheathing where necessary*

Remove rotted or warped sheathing boards or delaminated plywood and insi:all new decking.

Cover all large cracks, knot holes and resinous

areas with sheet metal,-

Repaint ferrous metal drip edges and other flashings that are in good condition or pembve badly

corroded metal ilashings and install new ones of npnferrous metal.

Remove old rollj. roofing flashings. Install new

base flashings of nop-ferrous metal or roll pooling,

and new non-/errous tnetal counter flashings.

Fill in with wood strips of the same thickness as

the existing sheathing the sp'aces betwen spaced sheathing to which a wood shingle, slate or tile roof had

been applied,^

Sweep all loose debris from the roof deck.
39 =

(2) When Existing Roofing Remains

(a) Reroof Ing Over Asphalt Roll Roofingjp

b Remove all ^oose and protruding^ nails

Cut all wrinkles and buckles and nail cut edges

securely to the rpor deck ^s illustrated in Figure 36.

Repaint ferrous metal drip edges and counter

flashings that are in good conditiono Install non^

ferrous metal drip edges at eaves pnd rake where none

exist 5 by removing nails ^ slipping the drip edge

under the existing roofing and renailing

Install new non-ferrous metal or roll roofing

base flashings and new metal counter "'flashings in

accordahce with "'hew construction specifications where

necessary

Install new non-ferrous metal or roll roofing

vallej- flashingSo

Sweep all loose debris from the roof decko

(b) Reroofing Over Asphalt Shingles <, Remove all loose or protruding nails

„

Nail down or 5 preferably ^ cut away the butts of

all curled Or lifted shingles

Treat flashings as described- in (a)o

Sweep all loose debris from the roof dacko
- ko

(c) Reroofing Over Wood Shingles,,

Remove all loose and protruding nails»

Nail down or cut off corners of warped shin^gleso

Replace decayed or missing shingles with new pneso

Cut back shingles at eaves and rake far enough tc>- apply 1 ino by h Ino wood strips securely nailed

o

Apply^ beveled wood strips approximately h in, wide

over each course of wood shingle So The thick side of

the strips should be as thick as the butts of the wood

shingles, with the other side feathered to negligible

thickness

c

Treat flashings as described in (a)»

Sweep all loose debris from the roof decko

B, Applying Asphalt-Shingle Roofo

Apply asphalt shingles in accordance with current

specifications for new construction except that -when

an asphalt- shingle roof is applied over an existing

asphalt-shingle 5 roll-roofing or wood-shingle roof,

1-3A ino nails should be used« Figure 37o

*+o3 Asphalt Roll Roofing

Federal Sp.ecif ications

s

SS-R-501, Roofing, Prepared; Asphalt, Smooth-Surf aced

o

SS-R-521, Roofing and Shingles; Asphalt-Prepared,

Miner al- Surf aced

«

SS-R-511, Roofing; Asphalt and Asbesto^s-Prepared

,

Mineral-Surf aced

o
-

*+o3ol Description and General Discussion

Asphalt roll roofing is roofing in sheet fj^orm composed of roofing felt^ saturated^, and coated on noth

sides 9 with asphalt which may or may not contain fdne

mineral ^tabilizero Asphalt roll roofing, like ^sphalt

built-up roofing,, may be smooth- surfaced^ or mineral

surfaced o Smooth- surf aced roll roofing may be dusted on both

sides with fine mineral matter such as talc, mica, or

fine §and, to prevent sticking in the rolls* Federal

Specification SS-R-501 covers smooth- surfaced roofing

in two weights, 55 and 65 lb* , the weights indicating

the weight per square applied » These roofings are made

with organic,-base felts, commonly referred to in the

roofing trade qs rag-base felts*

Single-thickness 5 smooth-surfaced roll roofing

should be used only on temporary structures with roof

slopes of not le^^ss than in* per foot*

V. Appljication is usually b^y the exposed nail method

with 2 in*, cemented laps* It may, however, be laid by

the conceded .nail method with cemented^laps not less

than 3 in* wide*

\ Mineral-surfaced roll roofing is composed of

either organic (rag) o^ asbestos roofing felt,

saturated, and coated. on^ both sides with asphalt

which may or may not contain fine mineral- stabilizer*

It is surfaced on the weather side with mineral granules embedded .in the asphalt coating* The nonweather side may be dusted with fine mineral matter

to prevent sticking* Mineral-surfaced roll roofing

is marketed in rolls 36 ft* long, in the following

styles? with the entire surface covered with granules;

with a or 4-in* bare" lapping- edge ; and with a 19 -in*

bare lapping edge, the latter being distinguished as
_ 1+2 -

"wide-selvage" roofing. Roofing with the entire surface

covere'a with granules is intended to be laid with a

2- in. lap and exposed nails. Those roofings with bare

lapping edges are intended to be laid with cemented laps

the width of the lapping edge and with, "blind” nailing,

that is, with one edge of the sheet of roofing nailed and

the other fastened only with cement, the nails being

covered by the cemented lap. This method of application

is preferred because it largely eliminates ~the "popping

out" common with exposed nails. See Figure 5® The

wider the lap, the betteT the service that may be expected

from the roofing.

Mineral- surfaced roll roofings lapped not more than

h in. should not be used on slopes of less than 4 ^n.

per foot. Wide-selvage roofing may be used on slopes as'

low as 2-1/2 in. per foot. With all types of roll»roofing, the steeper the slope, the better the service that

may be expected^ both in waterproofness and weather

resistance

.

Smooth- surf aced asphalt roll roofings weighing at

least 55 pounds per square applied and mineral- surf aced

roll roofings qualify for the Class C fire resistance

rating of the Underwriters’ Laboratories, Inc,, which

indicates that they are effective against light fire

exposures. Sheet roofings, composed of multiple plies

of asbestos felts and asphalt, with Class A and Class B

ratings, are also available. A Class A 'rating indicates

effectiveness'against severe fire exposure; Class B,

against moderate fire exposures.

4.3.2 Roof Decks for Asphalt Roll Rpofing Roofs

Roof decks for asphalt .roll roofing roofs should be

the same as for asphalt- shingle roofs. See Section

4.2.2.
- 43 »

4o3o 3 ..Storage and Handling of Asphalt Roll Roofing

Asphalt roll roofing ghould be handled carefully, at

all timesj but particularly during extremes ^of temperatureo

It is softened at high temperatures and embrittJ^ed at low

temperature s« Asphalt roll roofings stored in warehouses or on the

job ghould be stood on endo If several tiers are to" be

stored one on top of the other 5 boards should be placed

between the tiers to prevent damage to the ends of the

rolls.o Roll roofings stored on the job must be protected

from the weather

4o3o^ Deterijiining Treatment for Asphalt Roll Roofing

Roof s Smooth- surf aced asphalt roll roofings 9 being used

normally on temporary structures 9 should receive only the

minimum amount of maintenance or repair that will keep

them leakproof 0 The first effect qf normal weathering on smoqth-

surfaced i^oll roofing is the loss of the fine mineral

matter used to prevent sticking^ in the rolls o The

coating asphalt-, being exposed directly to the weather,

deteriorates more rapidly than that of mineral-surfaced

roofing* Recoating is usually required within 3 to 5

years* Recoating will be required earliest in hot,

humid areas and on buildings such as kitchens and washrooms where excessive moisture conditions prevail*

Weathering of mineral- surfaced roll roofing is

similar to that of asphalt shingles, that is, normal

weathering proceeds slowly and is first evidenced by

the loss of granular surfacing* Recoa^ing of mineralsurfaced roll roofing is not generally recommended

though it may be used to extend the life of a roof if

reroofing does not appear justified*
- -

Leaks at the seams of smooth and mineral- surfaced

roll roofings, applied with 2.-ino laps and exposed

nails, are the ^most common roll roofing failur^e., These

leaks a,re caused principally by inadequate lapping,

cementing or nailing of the- roofing, buckling of the

roofing at the seams, and loose nails.

h.3-5 Maintenance Methods - Asphalt Roll Roofing

A. Recoating Smooth-Surfaced Roll Roofings,

NOTE ; See Section 14,3 . 6, following , -for methods of

making minor repairs before the recoaxing qperation.

Smooth- surfaced roll roofing that has been exposed

from 3 to 5 years will usually show one or more of the

following conditions that indicate a need for recoating;

Asphalt coating alligatored or cracked, small coating

blisters cracked and broken and other small breaks in

the coating that expose the felt. Minor hail damage,

where the asphalt coating is damaged but the felt remains

intact, also indicates a need for recoatlng.

Treatment ; Remove all loose dust and dirt by

sweeping, vacuuming or air blast. Apply asphalt emulsion, asphalt-base roof coating or fatty-acid-pitch

base roof coating as described in Section 4ol.5-B,(l)-

c-1. Maintenance Methods - Smooth-Surf ac^ed Built-up

Roofs, ex-cept that the ^coating of asphalt primer

should be omitted in all but the most severely weathered

roofings,

B. Recoating Mineral-Surfaced Roll Roofings,

Because of the protection afforded by the mineralsurfacing granules, miner^al- surfaced roll roofing

weathers much more slowly' than the smooth- surfaced

type and, consequently, requires less maintenance. As

with asphalt- shingle roofing, by the time deterioration

through loss of granules becomes- serious, the condition

of the roofing will be normally such, through brittleness
- 45 -

and general deterioration, that recoating will not be

desirable. However, in cases where the future use of a

building is in doubt or where funds for reroofing are

not available, mineral- surfaced roofs may be recoated

as described for smooth- surf aced roofs. Mineralsurfaced roll roofing that has been in place not more

than half the. period it is expected to serve, but has

been damaged by hall, should be recoated if the damage

consists of lo§s of mineral surfacing without breaks in

the felt,

4 , 3.6 Repair Methods - Asphalt Roll Roofings,

Since repair methods for smooth- and mineralsurfaced roll roofings are identical, they are treated^

in this section,

A, Small Breaks (Nail hples, small breaks caused by

hail „or other mechanical damage, if limited in

number o

)

Treatment ; Apply asphalt plastic cement complying

with Federal Specification SS-C-153, Type I,

B, Large Breaks.

Treatment ; Large breaks are repaired as illustrated

in Figure 3b, by opening the 'horizontal seam below the

break and inserting through it a strip of roofing of the

type used originally. Extend the strip at least six

inches beyond the edges of Ihe break, with the lower

edge flush with the horizontal exposed edge of the

covering sheet. Coat the strip liberally with lap

cement where it will cpme in contact with the covering

sheet before inserting it. After inserting the strip,

press down the edges^of the roofing firmly and nail

securely with the nails about 3/4 in, from the edges

and spaced approximately 2. in. Apply lap cement to the

horizontal seam, press down firmly and renail J.f the

original seam was nailed.
- ^6 -

C. Large Areas

o

Treatment ; Where a considerable area has been

damaged, but the main area of the Toof remains intact,

remove the.. roofing from the damaged arpa and apply new

roofing of the same type, using full-width sheets

applied in the same manner as the original roofing*

Dc Repairing Leaky Seams of Roll Roofings*

Note ; It is assumed other necessary repairs will

be made prior to repairing the seams by this methods*

Leaks opcur most frequently at the seams of roll

roofings, caused by inadequate lapping, nailing or

cementing, loose nails, fishmouths, etc*

(1) For An Expected Use of Not More Than 1 Year,

Treatment ; Sweep the seams to remove accumulated

dust and dirt, cut all -buckles (fishmouths) which terminate at the seams, and insert a strip of roofing as

described in kol^o-B, Renail where necessary.

Apply asphalt plastic cement complying with Federal

Specification SS-C-I 535 Type I, to the seams, using a

trowel to feather the edge of the cement at the top of

the strip. Approximately 6 pounds of cement are required per square of roofing,

(2) For An Expected Use of More Than 1 Year,

Treatment ; Permanent repairs to leaky seams of

roll roofing roofs are best effected by using a membrane

such as cotton fabric or light-weight, smooth- surf aced

roll roofing, cemented over the seam and coated with a

bituminous c^ompound, A method that has been found to

be satisfactory is described here in detail. Modifications of this method, following the same principle, may

be satisfactory. With any method, careful workmanship

is as Important as satisfactory material.
- 47 -

Materials ; Four-inch strips of aephaltsaturated fabric (Federal- Specification HH-C-581,

Woven-Cotton Fabric^ Asphalt-Saturated), and asphaltc

roof coating (Federal Specification SS-R-45l^ Roof

Coating, Asphalt, Brushing Consistency, amended to

require at least 10 percent by weight of asbestos

fiber in lieu of 5 to 25 percent of mineral filler.

Quantities ; Quantities of materials required

per square (100 square feet) of roofing area;

Asphalt- saturated fabric strips - 39 lineal feet.

Asphalt roof, coating - approximately 4/5 gallon.

Application; Make repairs in clear mild- weath- / er when the outside temperature is 50°F or higher.

Sweep the seams to remove accumulated dust and dirt,

cut all buckles (fishmouths) which terminate at the

seams, and insert a strip of roofing as described in

Section 4 o3.6-Bo Replace all loose and missing nails.

Apply the roof coating to the seams in strlpsapproximately 6 inches wide. Use approximately 1

gallon of coating to 80 lineal feet of seam, and

work with a three-knot roofing brush or other satisfactory brush. Embejd the 4-lnch strip of saturated

fabric in this coating, pressing it firmly into the

coating until it lies flat without wrinkles or

buckles; the center of the fabric §trip must be

directly over the exposed edge of the roofing. Then

apply another coat of coating directly over the strip

of saturated fabric so the fabric is completely

covered and the first and second coatings are continuous. The strips of fabric can be handled most

easily if cut into approximately 12-foot lengths.
- -

Treat first the vertical seams of the roofing

next to the eaves, extending the cement and fabric

2 inches above the exposed *edge of the horizontal

seam. Next treat the horizontal seam next to the

eaves, placing the fabria directly over the top of

the fabric on the vertical seams. Finally treat the

vertical seams of the second sheet of roafing-y ’extending the fabric and coating over the fabric on the

first horizontal seam to its lower edge. " (See Figure

38,) Continue this >.al ternate treatment of vertical

and horizontal seams until all seams are repaired

.

Roof-coating materials of the type described

vary considerably in. consistency , composition,

setting time, and so on. In some cases, it may be

desirable to allow the first coating to become tacky

before applying the fabric, or to allow the first

coating with the fabric embedded in it to remain for

some time before applying the second coating.-

Effectiveness; This method is economical, easy

to apply, and not difficult to maintain. All the

materials used can be purchased under Federal Specifications. The fabric used as a reinforcing material

will give to a certain extend with changes in the

sheathing boards. Figure 38 illustrates the treat--

ment of seams of roll roofing by this method. Figure

39 is a general view and Figure hO a closeiu-p of

seams treated by this method; the seams '•having been

exposed approximately I8 months since the repairs

were made.

Maintain seams treated by this method by recoating them periodically with an asphalt coating of

the type used in the original treatment. In warm,

humid locations, recoating will probably be necessary

after I 8 months to 2 years; in other locations, after

2-1/2 to 3 years.
- 49 -

4o 3»7 Reroofing With Roll Roofings,

Preparation of the roof deck for reroofing with roll

roofings when the existing roofing is removed or over existing roll roofing, asphalt- shingle , or wood-shingle roofs

is identical with thal described for reroofing with asphalt

shingles. See Section 4.2.6, entitled Reroofing With

Asphalt Shingles. Roll roofings should be applied in

accordance with current specifications I’ or new construction except that, when applying roll roofings over existing asphalt- shingle , roll roofing or wood- shingle roofs,

1-3/4 inch nails should be used.

4.4 Asbestos-Cement Roofing

Federal Specifications?

SS-S-291, Shingles; Roofing, Asbestos-Cement.

SS-R-524, Roofing and Siding; Corrugated, AsbestosCement o

4e4,.l Description and General Discussion

Asbestos-cement roofing is composed mainly of Portland

cement and asbestos fibers. The mixture is formed, while'

wet, under pressure and is then cured, usually by steam.

Since it is composed entirely of inor.^anic materials,

asbestos-cement roofing is extremely resistant to normal

weathering. It is quite brittle initially and becomes

more brittle on long exposure. Asbestos-nement roofings

are produced in various shingle forms and in corrugated

sheets. American-method shingles should not be applied

on slopes of less than 4 in. per foot; all other types

on slopes not less than 6 in, per foot. Corrugated

sheets may be used on slopes of 3 inches per foot and

steeper

Shingles laid by the American method are usually

about 1/4 in. thick, the weight and number per square

varying with the different manufacturers, but in all
- 50 -

cases the American method provides greater weight -and

better coverage than any other type of shingle

»

Multiple-unit shingles and shingles laid by the

dutch-lap and hexagonal methods are normally about

5/32-in. thick and usually range in weight from 2^0 to

290 pounds, per square, though dutch-lap shingles laid

with a large side "lap may weigh as much as 370 pounds per

square

.

Asbestos-cement -shingle-s that provide two or more

thicknesses (American method) over a layer of l5-lb„

asphalt-saturated asbestos felt are eligible for the

Class A fire-resistance rating of the Underwriters'

Laboratories, Inc., which indicates that they are effective against severe fire exposure. Single-coverage

shingles (dutch lap or hexagonal methods) over l5-lb.

asphalt- saturated asbestos felt are eligible for the

Class B rating, indicating effectiveness against

moderate fire exposures.

A, A, 2 Roof Decks for Asbestos-Cement Roofs

A. Asbestos-Cement' Shingles

Wood decks for asbestos-cement shingle roofs

should be of well- seasoned sheathing lumber, not less

than 1 in. -in thickness, not more than 6 in, wide and,

preferably, tongued and grooved. The roof deck should

be kept dry at all times.

Sheathing boards should be fastened to each

rafter with two nails to provide a smooth, even surface.

The deck should be covered with l5-lb. asphaltsaturated felt prior to laying the shingles. This

underlayment i-s necessary to guard against the infiltration of wind and rain. In addition, it provides a cushion for the asbestos-cement shingles.
- 51 -

B„ Corrugated Asbe stos-Gement Sheets

Corrugated asbestos-cement sheets are normally laid

over open wood or steel framing,

5-A.3 Storage and Handling of Asbestos-Cement

Roofing

A, Asbestos-Cement Shingles

Asbestos-cement shingles should be kept dry at all

times. Exposure to moisture during transportation or

storage may cause discoloration of the shingles. Shingles

should be stacked on edge, preferably on planks at least

four Inches from the ground, If stored outdoors. Piles

of shingles should be not more than 4 fb, high.

Asbestos-cement shingles should be handled carefully to avoid breakage. If bundles are wired they

should not be lifted by the wires,

B, Corrugated Asbestos-Cement Sheets

Asbestos-cement corrugated sheets should be stored

and handled with the same care as asbestos-cement shingles, They should always be kept dry. Crated sheets

should not be uncrated until needed. When uncrated

they should be placed on firm, level supports, preferably on pieces 2 in, by 4 In, spaced 12 to l8 In, and

laid at right angles to the corrugations. Sheets

should not be stacked more than 4 ft. high. (Some

manufacturers recommend 2 ft.)

4,4,4 Determining Treatment for AsbestosCement Roofs

Investigation has shown that mechanical damage,

such as from hall, traffic, limbs of trees, warping of

the roof deck, etc,, and failure of fasteners, constitute the principal causes of maintenance and repair

work on asbestos-cement roofs.
- 52 -

If only a few shingles or corrugated sheets are

broken they should be removed and new ones applied* If

a lar-ge percentage (25 percent or more) are broken, they

should all be removed and a new roof applied. The age

and condition of undamaged units should determine whether

those salvaged from the old roof should be re-used with

new units.

When an asbestos-cement roof fails because of failure of the fasteners, the failure is usually a general

one and piecemeal repair is futile. When such failure

occurs, normally on a very old roof, it is best to remove the entire roof. Whether the old roofing should be

reapplied must be determined by its age and condition.

Normally, if the roofing can be removed without damage,

it may be reapplied safely.

No sharp distinction can be drawn between maintenance and repair work in asbestos-cement roofings.

Maintenance and repair methods are therefore treated

under one heading.

4 A. 5 Maintenance and Repair Methods - Asbestos-Cement Roofings

A. Asbestos-Cement Shingles

(1) Removing Broken Shingles and Applying New Ones.

(a) Shingles Applied by the American Method,

Follow the method described in Section 4,6,5-A.

for replacing a broken slate with a new one. This method

is illustrated in Figure hi. The same procedure can be

followed with multiple-unit shingles.

(b) Shingles Applied by the Hexagonal Method.

Straighten the anchors, shatter the shingle and

remove the broken pieces. Use the nail ripper to cut

or draw the nail. Punch a hole in a small piece of
- 53 -

copper, galvanized iron or painted tin, place over bottom

anchor and nail firmly to the roof deck. Notch a new

shingle to pass side anchors. Slide the new shingle into

place over the bottom anchor and bend down anchors to

hold it in place.

(c) Shingles Applied by the Dutch-Lap Method.

Remove the metal anchor and nails, then remove the

broken pieces of shingle. Insert a new shingle with a

new anchor. If the nails cannot be withdrawn, notch

the new shingle to avoid them.

B. Asbestos-Cement Corrugated Sheets

Broken asbestos-cement corrugated sheets should be

replaced with new ones, fastened in the same manner as

the original sheets. If this is not practicable,

toggle bolts with lead or plastic washers may be used.

These bolts pass through holes somewhat larger than

the bolt and when drawn tight, the washer forms a

waterproof seal.

^.^-.6 Reroofing with Asbestos-Cement Roofing

A. Asbestos-Cement Shingles

(1) Preparing Deck for Reroofing.

For instructions for preparing the roof deck for

reroofing with asbestos-cement shingles when the existing roofing is removed and when asbestos- cement shingles

are to be applied over an existing asphalt-shingle, rollroofing or wood-shingle roof, refer to Section e.2.6.

Reroofing with Asphalt Shingles, except that a 15-Ib,

asphalt- saturated felt should be applied over the woodshingle deck. While it is entirely possible to apply

asbestos-cement shingles over the roofings mentioned,

the long service that is normally expected of asbestoscement shingles indicates that the better practice is
- 5^ -

to remove the existing roofing ^ make the repairs to the

deck necessary to bring it to as nearly "new" condition

as practicable, and cover the deck with a'l^-ponnd

asphalt-saturated felt, laid horizontally, with a 4-in«

headlapo End laps should be a minimum of 6 in» except

at hips, ridges and valleys, where 12-in, laps are

recommended o Nail the felt with sufficient large- ' headed roofing nails to hold it in place during application of shingles,

(2) Applying Asbestos-Cement Shingle Roof,

Space limitations do not permit inclusion of instructions for applying all types of asbestos-cement shingles.

Step-by-step directions for installing multiple-unit

shingles are described below. Essentially this same

method is used for American method shingles. Detailed

instructions for applying other types can be obtained

from their manufacturers.

Starter Course

Lift up the edge of underlayment at the eaves

and lay a full-size starter shingle. Let it overhand the eaves and gable approximately 1 in, and

secure it with four galvanized nails. Apply succeeding starters, spaced l/l6-in, apart, in the

same manner until entire course is laid.

First and Succeeding Courses

The first course of the main roof is laid di:-

rectly over the starter course starting with a half

shingle with the vertical edge projecting 1 in,

beyond the gable and the butt edge projecting 1 in,

beyond the eaves. Fasten each shingle with four

galvanized nails. Do not drive nails "home" as in

laying wood shingles. Lay the second course with a

full-size shingle so that the shoulder coincides
- 55 -

with the point of the underlaying course. A 6-in.

exposure is automatically obtained. Start the succeeding course with a half- size shingle, then a fullsize shingle, alternating with each course.

Hip and Ridge Finish

Lay roof shingles so that they butt closely

against furring strips placed at hips and ridges.

Cover furring strips with asbestos felt and apply

hip and ridge shingles. Start laying the ridge

shingles on main roof at the end of the ridgefarthest away from prevailing storms. When covering

hips, start at the lower end. Fasten each shingle

with two nails and point up with slaters cement.

Nails

Large-head, galvani-zed, needle-point roofing

nails should be used. For new roofs, 1-1/^ in.

nails are adequate; for application over existing

roofs, 2-in. nails should be used.

B. Asbestos-Cement Corrugated Sheets

Asbestos-cement corrugated sheets should be applied

in accordance with current specifications for new construction. Manufacturers of asbestos-cement corrugated

sheets maintain engineering and estimating services to

assist users in determining the quantities of materials

required for particular jobs. At least two manufacturers should be consulted.
- 56 -

4„5 Metal Roofing

^<,5ol 'Description and General Discussion

Metal roofings may be of copper 5 terne (tin), galvanized steel, aluminum, or so-called protected metal.

The various kinds will be discussed separately, but -cer- tain factors which apply to all kinds are discussed jointly.

For a more detailed discussion of metal roofing, see

National Bureau of Standards Building Materials and Structures Report BMS ^9, "Metallic Roofing for Low-Cost House

Construction"

,

A, Expansion and Contraction.

All metals used in roofing expand and contract with

changes in temperature. This must be taken into account

in designing metal roofs. Actually, most metal roof

forms owe their design in large part to the necessity

for providing for expansion and contraction. 1

The rate of expansion and contraction differs with

each metal. Some idea of the magnitude of the change

for which provision must be made is given below, where

the figures represent the expansion or contraction of

an 8 -ft, sheet with a 150°F variation in temperatures

Changes in dimensions with changes in temperature

result equally in all planes of the metal and are the

same regardless of the thickness of the metal. Thus,

a 1-ft, square piece of thin copper or aluminum foil

will change as much in length and width as a thicker

piece of the same size under similar temperature differences.

Iron

Copper

Aluminum

6/64 in,

9/64 in,

12/64 in.
- 57 -

Because of changes in dimensions with changes in temperature, metal roofs laid in summer require adequate provision for contraction, but little provision for expansion.

Conversely, metal roofs laid in cold weather require adequate provision for expansion, but little provision for

contraction.

B. Galvanic Action.

In metal roof construction it is frequently Impossible

to prevent the contact of dissimilar metals, which may result in the corrosion of one of the metals ‘and the protection from corrosion of the metal in contact with it. This

is the so-called galvanic action or electrolysis which

occurs when metals of different position in the electromotive series are in intimate contact in the presence of

an electrolyte. The metals commonly used for roofing are

listed in the electromotive series in the following order:

When any two metals in this list are in contact in the

presence of an electrolyte, the one with the lower number is corroded. Also, the farther apart the metals

are, the greater will be the corrosion. Thus, with iron

and copper in contact in the presence of water, the iron

would be corroded more than lead in contact with copper

under similar conditions. Any means that separates dissimilar metals will protect against this action. Frequently used are layers of waterproof building paper or

asphalt-saturated felt, or a coating of asphalt paint.

1 . Aluminum

2. Zinc

3. Iron

Tin

5. Lead

6, Copper
_ 58 ~

Co Types of Metal RoofingSo

Metal roofings are classified into three general

typess Flat sheets 5 corrugated sheets and unit roofings

made in the form of shingles or tiles* Special shapes

of some metal roofings are also available*

(1) Flat Sheets*

Flat metal sheets are assembled for roofing purposes

by means of various seams, commonly designated as batten

seams, standing seams and flat seams*

Batten-Seam Roofing ; In batten- seam roofing, metal

sheets are formed over ribs or battens, of wood or metal,

which divide the roof- into small areas and provide adequately for expansion and contraction in the direction

perpendicular to the battens* Expansion and contraction

in the direction parallel to the battens is provided best

by unsoldered flat-lock cross seams* Soldered cross seams

are sometimes used with the expectation that allowance

for expansion and contraction is made at the eaves and

ridge or that the soldered seams so stiffen the sheets

that slight buckling within each sheet will occur at

elevated temperatures*

Standing-Seam Roofing ; Standing-seam roofing is

similar to batten-seam roofing in that it divides the

roof into relatively small areas and provides for expansion and contraction in the direction perpendicular

to the seams* The roofing sheets are fastened to the

roof deck by means of cleats spaced not more than 12 in*

apart, nailed to the roof sheathing at one end and folded

into the seam at the other* Since standing seams are

unsoldered, they should not be used on roofs with slopes

of less than 2 in* per foot and should preferably be

used with slopes h in* per foot or greater*
- 59 -

Flat-Seam Roofing ; Flat-seam roofing, forming a continuous sheet, is adaptable to low-pitched roofs, preferably not less than 1/2 in, per foot, to insure proper

drainage. Small sheets, usually 1^ by 20 in,, are fastened to the roof deck by means of cleats, one end of

which is soldered to the sheet and the other nailed to

the roof deck, A flat-lock seam is then formed at the

juncture of the sheets and the seams sealed with solder.

While the sheets are held in place firmly by the cleats

and sufficient elasticity is provided to take care of

expansion and contraction, large roof areas covered by

this method should have the extremities of the roof

covering free or expansion joints should be provided

at regular intervals.

Occasionally long sheets of roofing are applied

by the flat-seam method,

(2) Corrugated Roofing,

In corrugated roofing, series of parallel alternate

ridges and grooves or crests and vales (hills and valleys)

are formed in flat metal sheets. These features add

stiffness to the sheets, increase the load-carrying

capacity and aid in discharging rain water.

(3) Unit Roofings,

So-called metal shingles made to simulate the appearance of slate and forms made to imitate the various kinds

of tiles comprise most metal unit roofings. Because of

the small size of unit roofings, no provision for expansion and contraction is necessary.
- 60 -

Do Fire Protectiono

Metal roofs 5 generally , are not classified as regards

resistance to fire hazards o However , structures with

metal roofs usually are eligible for the lowest insurance

rates because of the protection afforded from falling

sparks and ember So

4o5o2 Roof Decks for Metal Roofings

Metal roofings are applied on solid or open-slat

wood decks 5 or on wood or metal framing (purlins)

o

Solid wood decks may be of well-seasoned 5 tongued-andgroovedj square-edged or ship-lap sheathing laid to

produce a smooth ^ uniform surface o In open- slat decks,

the sheathing boards may be spaced from 6 to 24 ino , depending on the rigidity of the roofing to be applied

o

Only the more rigid sheet roofings, usually corrugated,

are laid on purlins without sheathing

o

Metal roofing may also be laid over concrete or

gypsum roof decks o Some underlay material such as

asphalt-saturated felt is usually applied under metal

roofing on tight deckSo Contact of dissimilar metals

should be avoided

o

4o5o3 Storage and Handling of Metal Roofing

Metal roofings in storage should be protected from

the weather o Although some metal roofings are intended

for direct exposure to the weather, some, such as

copper, may become stained and others, such as galvanized sttel, may corrode if stored in a damp place

o

Metal sheets should be stored on edge, not in contact

with the ground

o
6l -

4 . 5 .^ Determining Treatment for Metal Roofs

Since the different metal roofing materials normally

require different treatments, they are considered separately in this section.

A, Copper Roofing.

Copper is one of the least chemically active metals

used for roofing. Consequently, copper roofings of adequate weight, applied properly, render long service.

The weight of copper roofing is designated as ounces per

square foot. Sixteen-ounce copper is the generally

accepted weight for roofing. Sheets of this weight are

approximately 0.022 in. thick and, when applied by the

standing- seam method, weigh approximately 125 lb. per

square. Copper roofs are usually applied by the flatseam, batten-seam or standing-seam methods.

When copper roofing is exposed to the atmosphere

a green coating known as patina forms on the exposed

surface. This coating aids in protecting the metal

from further corrosion.

Lead-coated copper is occasionally used for roofing, While this is a case of dissimilar metals in

contact, lead and copper are adjacent in the electromotive series so that little action would be expected

in any case. Since lead has the lower number, it protects the copper electrolytically as well as physically.

The most common cause of failure in copper roofs

is the failure to provide adequately for expansion and

contraction, particularly in flat-seam roofing. Broken

soldered seams and breaks in the metal at points other

than seams indicate inadequate provision for expansion

and contraction.
- 62 -

Copper roofs do not normally require maintenance as

defined for this manual o Any treatment necessary would

be classed as a repair^ following failure (leak)o

(1) Repairing to Provide Adequate Expansion and

Contractiono

(a) Flat-Seam Roofs

o

When broken soldered seams indicate inadequate provision for expansion and contraction, new expansion

joints ^sufficient to provide a joint at intervals of not

more than ten feet in each direction should be installed

»

(b) Batten- and Standing-Seam RoofSo

If soldered horizontal seams on batten- and standing- seam roofs are broken, loose lock seams that permit

movement of the sheets should be Installed at those

points o

(2) Repairing Breaks in Copper Roofing

o

(a) Small Breaks

Small holes in copper roofing can be repaired with

a drop of solder „ In soldering copper, scrape with a

sharp instrument or emery cloth until bright metal shows

on any surface that is to contact the solder,, Then apply

zinc chloride or rosin as a flux and tin the surface with

a thin coating of solder

o

(b) Larger Breaks

Larger breaks, not caused by inadequate provision

for expansion and contraction, may be repaired by soldering a piece of copper over the holeo
- 63 -

(3) Reroofing with Copper Roofing,

(a) Preparing Deck for Reroofing with Copper

Roofing

Restore the deck to as nearly "new" condition as

possible, as follows:

Remove all protruding nails and renail sound sheathing where necessary.

Remove rotted or warped sheathing boards and install

new decking.

Cover all large cracks, knot holes and resinous areas

with sheet metal.

Repair or replace copper flashings,

(b) Applying Copper Roof

Apply copper roof in accordance with current specifications for new construction,

B. Terne Roofing

Federal Specification QQ-T-201, Terne Plate for

Roofing (Roofing Ternes),

Terne (tin) roofing is composed of an iron or steel

sheet coated on both sides with a lead-tin alloy, Terne

sheets are usually furnished in grades 1C (approximately

No. 30 U.S, Gage) and IX (approximately No. 28 U.S. Gage),

The 1C grade, weighing approximately 65 pounds per square,

is generally used for flat-seam, batten-seam and standingseam roofing. The IX grade, weighing about 25 percent

more than the 1C grade, is normally used for flashings,

valleys and box gutters.
- 6^ -

Sheets are generally available in two sizes , 1^- by

20 ino and 20 by 28 in^ The larger sheets are normally

used in standing-seam construction^ the smaller ones in

flat-seam construction® Rolls containing 100 sq® ft®

in widths of 20 or 28 in® are also available®

The weight of lead-tin coating for terne sheets is

designated as "pounds per base box" ^ a base box consisting of 122 sheets 5 20 by 28 in® (^35® 56 sq® ft®)®

Standard roofing practice calls for a minimum coating

of 25 lb® per base box^ corresponding to a total of

Oo9184 oz® per sq® ft® on both sides of the sheet®

The coefficient of expansion of terne sheets is

only about 2/3 that of copper ^ therefore ^ expansion and

contraction with changes in temperature is less of a

problem® In addition^ the lighter weights of terne

sheets that are used permit slight buckling®

It is necessary to keep terne roofing well painted

for long service® The reason is that the lead-tin alloy,

while furnishing good physical protection to the iron or

steel base, is so placed in the electromotive series that

the coating will be preserved at the expense of the ferrous base in cases where pinholes or scratches in the

coating expose the base®

The most frequent cause of failure in terne roofs

is the lack of regular maintenance painting®

Many leaks in terne roofings are caused by faulty

seams ®

(1) Maintaining Terne Roofs®

Terne roofs must be maintained by periodical painting® The frequency of painting will vary with different

conditions of exposure, but painting should never be put
- 65 -

off until rust appears nor should thick coatings of paint

be built up by too frequent painting.

Instructions for painting terne roofs are given in

current publications.

(2) Repairing Terne Roofs.

(a) Broken Soldered Seams.

Broken soldered seams should be resoldered, following

the precautions given for soldering copper in Section 4.5®^-

A. (2)(a).

(b) Leaky Formed Seams.

Repair leaky formed seams by reforming or by calking

with a plastic calking material.

(c) Small Breaks.

Repair small holes in terne roofings with a drop of

solder.

(d) Larger Breaks

Larger breaks in terne roofings may be repaired by

soldering a piece of terne roofing over the break.

(3) Reroofing with Terne Roofing.

(a) Preparing Deck for Reroofing.

See Section V. 5»^-A. (3 ) (a)

,

"Preparing Deck for Reroofing with Copper Roofing"*

(b) Applying Terne Roof.

Apply terne roof in accordance with current specifications for new construction.
66 -

C. Galvanized Steel Roofing

Federal Specification QQ-I-716, Iron and Steel;

Sheet, Zinc-Coated (Galvanized).

Galvanized sheets are available in various sizes and

in thicknesses ranging from No» 12 to 30 gage and in various weights of zinc coating, the weight of coating being

expressed as the total weight of zinc per sq« ft. on both

sides of the sheet.

The resistance to corrosion of galvanized sheets

increases with increased weights of zinc coating. However, since the sheets are formed after the zinc coating

is applied, there are practical limits to the thickness

of the coating on formed sheets. The heavier coatings,

up to 2,75 lb., are normally applied to the heavier gage

sheets. Zinc-coated sheets should be specified by

weight in pounds per square foot.

For severe bending or forming, only thin, tightly

adherent coatings are used. Zinc is an ideal coating

material for iron or steel. From its position in the

electromotive series it is obvious that the base metal

will be protected electrochemically by the zinc in cases

where pin holes or scratches expose it, and it is only

when relatively large areas of the base metal are exposed that rusting takes place. Consequently, unlike

terne coated sheets, galvanized sheets may be exposed

without painting. The length of such exposure depends

on the weight of the zinc coating and the conditions of

exposure, but painting may be postponed safely until

the first sign of base metal corrosion appears. This

will be in the form of a rather bright yellow product

resulting from the corrosion of the zinc-lfon alloy

formed on the surface of the base metal.
- 67 -

The common types of galvanized roofing are V-crimp,

corrugated, pressed standing seam, rolled roofing and

shingles. All but the roll roofing are pre-formed, ready

to apply. Other special shapes of pre-formed sheets are

also available.

Corrugated galvanized roofing is the lowest in cost

of all types of metal roofing and, when properly applied

and maintained, it renders very satisfactory service.

Since it is the type of galvanized roofing used most frequently on warehouses, sheds, etc., it is taken as representative of the galvanized metal roofings.

Corrugated galvanized roofing may be applied over

tight wood decks, with or without underlay, on open- slat

decks or on wood or steel purlins. It is available in

sheets of different lengths and depths of corrugations.

The most frequent causes of failure in galvanized

roofings are improper application and lack of regular

maintenance painting. Leaks at seams and fasteners are

evidence of improper application.

Galvanized steel sheets should be secured with galvanized steel or aluminum-alloy fasteners in order to

avoid galvanic attack on the sheet,

(1) Maintaining Galvanized Steel Roofing,

Galvanized steel roofs need not be painted immediately upon exposure. In fact, without special treatment or the use of special paints, it is better to

postpone painting of galvanized steel for several months,

at least, to insure adhesion of the paint. Painting may

be postponed until the appearance of a bright yellow

corrosion product indicating that the zinc coating is
68 -

no longer protecting the zinc-iron alloy formed on the

surface of the base metals It is much safer to paint

prior to the appearance of this product and subsequent

regular maintenance painting will prolong the service

of the roofing indefinitely.

Instructions for painting galvanized steel roofs

are given in current publications on painting,

(2) Repairing Galvanized Steel Roofs,

(a) Leaks at Seams and Fasteners,

Inadequate laps in galvanized steel roofings may be

repaired by calking the seams or, in severe cases where

calking is impracticable, by stripping the laps as described in Section ^-.3 » 6-D, (2)

,

Repairing Leaky Seams of

Roll Roofings for An Expected Use of More Than 1 Year,

As stated in this reference, modifications of the method,

following the same principle, may be satisfactory. With

any method, workmanship is extremely important. It

should be realized, also, that repairs of this kind cannot be expected to last as long as the galvanized sheets

so that they will require maintenance treatment and

probably renewal at intervals.

When exposed fasteners are a part of the lapped

seam, the membrane treatment should be applied over them,

(b) Repairing Breaks in Galvanized Steel Roofing.

Breaks in galvanized steel roofing are best repaired

by replacing the defective sheet of roofing with a new

one

.
- 69 -

(3) Reroofing with Galvanized Steel Roofing.

(a) Preparing Deck for Reroofing.

See Section (3 ) (a) , "Preparing Deck for Reroofing with Copper Roofing".

(b) Applying Galvanized Steel Roof.

Apply galvanized steel roof in accordance with current specifications for new construction.

D. Aluminum Roofing

Aluminum roofing materials may be homogeneous, with

the entire cross section of the same composition, usually

not less than 97 percent of aluminum, or they may be socalled clad materials, with a layer of aluminum or aluminum alloy that is anodic to the core material and which

will retard corrosion of the core material if it is exposed, The usual core material is an aluminum alloy,

though aluminum-clad steel sheets have been used.

Aluminum roofings are available in essentially the

same forms as galvanized steel, namely V-crimp, corrugated, pressed standing seam and shingles. Other special shapes are also available. Sheets are produced

in various sizes and thicknesses and in varying degrees

of temper.

Aluminum roofing has only recently come into general use, but, when properly applied, it is known to

render excellent service. It is similar to copper

roofing in that it does not require painting. However,

the coefficient of thermal expansion of aluminum is

approximately one-third greater than that of copper so

that ample provision for expansion and contraction must

be supplied when long sheets of aluminum roofing are

used

,
70 -

Contact of aluminum roofing with dissimilar metal

must also be avoided, particularly in coastal areas*

This precludes the use of bare steel and copper nails,

or lead washers, in such areas. Aluminum alloy nails

should be used with aluminum alloy roofing to obtain

the best results.

(1) Maintaining Aluminum Roofing.

Aluminum roofing, properly applied, does not normally require maintenance. However, if evidence of

severe atmospheric corrosion occurs, the roofing may

be preserved by regular maintenance painting. Instruc

tions for painting aluminum are given in current publi

cations,

(2) Repairing Aluminum Roofing,

Failures in aluminum roofing that are due to improper application are essentially the same as those

encountered with galvanized steel roofing and are

repaired similarly. See Section 4.5»^-C.(2), "Repairing Galvanized Steel Roofs",

(3) Reroofing with Aluminum Roofing,

(a) Preparing Deck for Reroofing.

See Section 4, 5,^-A. (3 ) (a) , "Preparing Deck for

Reroofing with Copper Roofing",

(b) Applying Aluminum Roofing.

Apply aluminum roofing in accordance with current

specifications for new construction.
71 -

E, Protected Metal Roofing

Protected metal roofing takes its name from the fact

that it consists of a steel base sheet that is protected

from the weather by a factory-applied covering. In one

type, the covering is an asphalt-saturated, asbestos felt

bonded to the steel core on both sides and coated with a

waterproof coating. In the other type, the covering is

simply an asphaltic compound that is applied to both sides

of the sheet and surfaced with fine mineral matter.

Protected metal roofing is available in sheets of

different size and unit weight, depending upon the gage

of the metal core and the type of covering. It is also

available in different shapes, though the corrugated

form is in most general use.

Protected metal roofings are definitely proprietary

materials with only limited sources of supply. Consequently, with these materials, the recommendations of

the manufacturer should be followed as regards storage

and handling, application, maintenance and repair.

With materials of this kind, it is practically impossible to avoid some breaks in the protective covering

during application. To cover such breaks and to renew

the protective coating when exposure makes a renewal

necessary, only materials furnished by the manufacturer

should be used in order to insure that the new material

is compatible with the old.
72 -

4.6 Slate Roofing

Federal Specification SS-S-451, Slate; Roofing.

4.6,1 Description and General Discussion

Slate is a natural rock which was formerly much

more widely used as a roofing material than at present.

Consequently, most slate roofs that are encountered are

old ones, on permanent structures. Some of the oldest

roofs in the country are of slate, slate roofing having

been produced for more than 200 years.

Slate colors are designated Black, Blue Black, Gray,

Blue Gray, Purple, Mottled Purple and Green, Green (fading and unfading) and Red,

Most roofing slate has been produced in two counties

in eastern Pennsylvania, although the colored slates

from western Vermont and eastern New York and the gray

(Buckingham) slates from Virginia have also been used

widely. The quarries that produced the earliest, and

possibly the most enduring, slates on the PennsylvaniaMaryland border (Peach Bottom) are no longer operated

for roofing slate.

The eastern Pennsylvania slates are classed as

"fading" slates, in that they change color on long

exposure, the most common form of fading being that

where the sides and bottom of the exposed portion of the

slate changes to a light gray or tan, which will eventually spread over the entire exposed surface. This

change may start in a relatively short time, 10 to 12

years, with slates of poor quality. It is usually accompanied by a partial disintegration of the faded portion.

However, many such roofs that have rendered from 50 to

60 years of satisfactory service are known.
73

The New England and Virginia slates generally render

excellent service, roofs of these slates more than eighty

years old being not uncommonc

Roofing slate is quite brittle and becomes more

brittle on exposure. It is produced in a variety of

sizes and is usually laid by the American method.

Roofing slate is normally 3/l6-in. thick, but on monumental jobs may range in thickness from 3/16 to 2 in.

for architectural effect. Slate roofs may vary in

weight per square from 650 to 8000 lb, , depending upon

the thickness.

Roofing slate is not classified as to fire resistance by the Underwriter’s Laboratories, Inc., but a reasonable classification would be one similar to that

for asbestos-cement shingles,

4,6,2 Roof Decks for Slate Roofs

Wood decks for slate roofs should be of wellseasoned sheathing lumber, not less than 1 in, in

thickness, not more than 6 in. wide and, preferably,

tongued and grooved. Specifications formerly suggested

8 or 10 in, widths, but the narrower boards cause less

breakage.

Sheathing boards should be fastened to each rafter

with two nails to provide a smooth, even surface.

The deck should be covered with a 30-lb. asphaltsaturated felt prior to laying the slates. The roof

deck should be kept dry at all times.
- 7^ -

4o6o3 Storage and Handling of Slates

Roofing slates should be handled carefully to avoid

breakage. They should be stacked on edge, preferably on

planks, to give a firm, level support. Tiers of slate

should be separated by wooden lath placed 1 in. from the

outside edges of the slates. Slates should normally not

be stored more than 6 tiers high. When stored outdoors

they should be covered, particularly in freezing weather,

4-, 6,4 Determining Treatment for Slate Roofs

As with asbestos-cement roofing, mechanical damage,

such as that from hail, traffic, limbs of trees, warping of the roof deck, etc,, and failure of fasteners,

constitute the principal causes of maintenance and repair work on slate roofs.

Actual failure of the slate due to weathering will

occur eventually. With slate of poor quality this may

happen in less than 2^ years. With slate of good

quality it may be after more than 100 years of exposure

and usually after the slates have been relaid because

of the failure of the original fasteners.

If only a few slates are broken they should be removed and new ones applied. If a large percentage are

broken (25 percent or more), they should all be removed

and a new roof applied. The age and condition of the

undamaged slates should determine whether those salvaged from the old roof should be re-used.

No definite criteria can be given for determining

whether a slate should be re-used. However, if the

part that has been exposed is not faded appreciably
- 75 -

and shows no evidence of disintegration; if the unexposed

portion, either side, shows no disintegration; and if the

slate gives a sound "ring" when it is held between thumb

and finger by one corner as lightly as possible and

struck a sharp blow by the knuckles, it may be safely

re-used

When the failure of a slate roof is due to failure

of the fasteners, the failure is usually a general one,

and, as with asbestos-cement roofing, piecemeal repair

is futile, and it is best to remove the whole roof.

Whether the old slate should be reapplied must be determined by its age and condition. A case is known

where slate applied originally about I87O were removed

because of failure of the nails and successfully reapplied during World War II.

No sharp distinction can be drawn between maintenance

and repair work in slate roofing. Maintenance and repair

methods are therefore treated under one heading.

4 . 6.5 Maintenance and Repair Methods - Slate Roofs

A. Removing Broken Slates and Applying New Ones

Remove the broken slate and cut the nails with a ripper. Insert a new slate of the same color and size

as the broken one and nail it through the vertical

joint of the next course above, driving the nail about

2 inches below the butt of the slate in the second

course above. Force a 3- by 6-inch or larger strip of

copper under the course above the nail and bend the

strip slightly concave to hold it in place. The strip

usually will extend about 2 inches under this course

and will cover the nail and extend 2 inches below it.

(See Figure 41.)
- 76 -

^.6.6 Reroofing With Slate

A. Preparing Deck for Reroofing,

For instructions for preparing the roof deck for re

roofing with slate when the existing roofing is removed

and when slate is to be applied over an existing asphalt

shingle, roll-roofing or wood- shingle roof, refer to

Section ^„2o6, "Reroofing with Asphalt Shingles", except

that a 30-lbo asphalt-saturated felt should be applied

over a wood-shingle roof before applying the slateso

When slate is used to replace a lighter material or when

it is applied over another material, the roof framing

should be checked to determine whether it has adequate

strength. As with asbestos-cement shingles, the long

service that is normally expected from a slate roof

indicates that the better practice is to remove the

existing roofing, make the repairs to the roof deck to

as nearly "new" condition as practicable and cover with

a 30-lb. asphalt-saturated felt laid horizontally with

a 4— in, headlap and 6-in, end laps. Secure the felt

with large-headed roofing nails as necessary to hold

it in place until covered by slate.

B, Applying Slate Roof.

Starter Course

Apply a cant strip of suitable thickness, depending upon the thickness of the slate, at the eaves.

Lay the starter course over the cant projecting 2

inches at the eaves and 1 inch at the gable. Fasten

each slate with two large-headed slating nails. Drive

the nails so that their heads just touch the slate.

Do not drive nails "home". The length of the starter

course may be found by adding 3 inches to the exposure

being used on the regular slate, while the thickness

depends upon the thickness of the slate.
77 -

First and Succeeding Courses

Apply the first course of slate over the starter

course with the butts of both courses flush and the joints

broken. Fasten each slate with a minimum of 2 largeheaded slating nails. Apply the second and succeeding

courses with a headlap of 3 inches and joints broken.

Bed all slates on each side of hips and ridges within

1 foot of the top and along rakes within 1 foot of the

edge in approved elastic cement and cover all exposed

nail heads with elastic cement. Lay slate roofs with

open valleys.

Nails

Nails for slating should be of non-ferrous metal

and of proper size. Large-headed copper nails are satisfactory. For commercial standard slates, l8 inches or

less in length, use l-lA-in. nails; for longer slates,

1-1/2- in, nails should be used. A good rule to use in

determining the proper size nail is to add 1 inch to

twice the thickness of the slate. Two-inch nails

should be used on hips and ridges.

4,7 Tile Roofing

4,7.1 Description and General Discussion

Most roofing tiles are clay or shale products that

are burned to a hard, dense structure, with or without

a glazed exposure surface. A few cement tiles have been

produced

,

Several types of tiles are used for sloping roofs,

namely, shingle, Spanish, mission and interlocking, but

in these general types there are many variants in size,

form and color.
- 78 -

The so-called promenade tiles used for surfacing

flat, built-up roofs that are subjected to traffic are

usually square-edged shale tile not less than 3 /^ in.

thick.

Tale roofs are extremely heavy, ranging in weight

from 800 to 1800 Ibo per square 5 consequently, they

require very strong framing to support them. Tiles,

except promenade tiles, should not be laid on slopes

of less than 4 in, per foot.

Roofing tiles are not classified as to resistance

to fire by the Underwriters* Laboratories, Inc., but

since they are fireproof they should be rated at

least equal to asbestos-cement and slate roofings.

4.7.2 Decks for Tile Roofs

A. Sloping Decks.

Wood decks for tile roofs should be of wellseasoned sheathing lumber, preferably tongued-andgrooved and not more than 6 in. wide.

Sheathing boards should be fastened to each rafter

with two nails to form a smooth, even surface.

The roof deck should be covered with 30-lb« asphaltsaturated felt prior to laying the tiles.

Concrete decks with nailing strips and nailable concrete decks are also used.
79 -

B, Flat Decks.

Promenade tile on flat decks are laid over a conventional asphalt or coal-tar-pitch built-up roof, usually

5 ply, with a final mopping of 25 pounds of asphalt or

coal-tar pitch instead of the usual heavy pouring of bitumen specified for roofs surfaced with slag or gravel.

Promenade tiles should be laid in a bed of cement

mortar (1 to 3) approximately 1 in. thick. Joints should

be 3/16 to 1/4 in, wide, filled flush with cement mortar

(1 to 2), Expansion joints, 3/4 in. wide, filled with a joint- sealing compound, should be provided on l5-ft.

centers and at skylights, curbs and walls. Expansion

joints should extend from the top of the tile through the

cement mortar to the bituminous membrane,

4.7.3 Storage and Handling of Tiles

Store and handle roofing tiles as described in Section 4,6,3, "Storage and Handling of Slates",

^-,7.4 Determining Treatment for Tile Roofs

A, Sloping Roofs.

Mechanical damage, such as that from hail, traffic,

tree limbs, etc,, and failure of fasteners constitute

the principal causes of maintenance and repair work on

tile roofs.

The principles that determine the treatment for

sloping tile roofs are essentially the same as those

for determining the treatment of slate roofs, except

that occasionally, after very long periods of service,

tile roofs that are in otherwise satisfactory condition

may leak because of the disintegration of the felt

underlayment
80 -

Flat Roofs with Promenade Tile,,

The most frequent cause of maintenance or repair work

on a promenade tile roof is that necessitated by too few

expansion joints between the promenade tile or by permitting

the expansion joints to become filled with non-resilient

material. Maintenance and repair methods for the built-up

roof membrane are discussed under Built-Up Roofing,

Maintenance and repair methods for tile roofs are

treated under one heading since no clear-cut distinction

can be made between them,

4 . 7.5 Maintenance and Repair Methods - Tile Roofs

A, Sloping Roofs,

Replace broken shingle tiles with new ones by the

method described for replacing broken slates, Section

4.6,5-A, Replace broken Spanish tiles by troweling

Portland cement mortar on the new tile surface that will

be lapped by the tile in the course above and on the surface that will lap the tile in the course below. Fasten

the new tile in place with copper wire. Interlocking

tiles use special fastenings and are replaced easily.

It is sometimes impossible to match the exact shape or

color of very old tiles. When a number of buildings

are roofed with the same kind of old tiles, it may be

necessary to re-roof the first with new tiles that

match the old as nearly as possible, keeping sound

tiles salvaged from the first roof to patch the other

roofs and to replace tiles broken when the other roofs

need to be reroofed.
81 -

B. Promenade Tile on Flat Decks.

When insufficient expansion joints cause raising of

the promenade tile, new joints should be installed. Expansion joints on 10-ft. centers and at skylights, curbs

and walls are considered adequate.

If expansion joints have become filled with nonresilient material or if the expansion joint material

has deteriorated, it should be raked out and new material installed.

4,7*6 Reroofing with Tiles

A. Sloping Roofs.

(1) Preparing Deck for Reroofing.

Existing roofing should be removed and the roof deck

restored to as nearly "new" condition as practicable by

removing rotted or warped sheathing boards and replacing

them with new ones, and applying a 30-lb, asphaltsaturated felt horizontally, with a 4-in. headlap and a 6-in. side lap. Secure the felts along laps and exposed

sheets with large-headed roofing nails as necessary to

hold it in place until covered by tile.

(2) Applying Tile Roof,

(a) Mission and Spanish Tiles,

Before starting to lay tiles, mop the wood nailing

strips with hot asphalt and fill spaces back of cant

strips with asphaltic cement. Lay tiles with open

valleys. Set eaves closures back 3 inches from the lower

edge of eaves tiles. Lay pan tiles with uniform exposures to the weather. Lay cover tiles in a uniform

pattern, except where otherwise necessary to match existing roofs. Give all tiles a minimum lap of 3 inches
- 82 -

and extend pan tiles 1 inch over rear edge of gutter,,

Cut tiles to meet projections with finished joints and

point up with roofer's cemente Waterproof the spaces

between field tiles and wood nailing strips at ridges

and hips with a fill of roofer's cemento Fit all tiles

properly and then secure them with nails long enough to

penetrate at least 1 inch into the wood base. Fill

spaces between pan and cover tiles in first row at

eaves solid with cement mortar composed of 1 part portland cement, 3 parts fine sand, and enough clean water

to form a plastic mix. Wet all tiles before applying

mortar, and then press them firmly into the mortar bed*

Match the tile courses on dormer roofs with those on

the main roof. Cut surplus mortar off neatly. Point

up all open joints. Remove loose mortar from exposed

surfaces.

Where winds of hurricane intensity can be expected,

consideration should be given to reinforcing tile roofs

by laying all field tiles in portland cement mortar. To

do this, fill the ends of tiles at eaves, hips, ridges,

rakes, and spaces beneath ridges, solid with cement

mortar and fill the full width of laps between the tiles,

both parallel and perpendicular to the eaves, with cement

mortar.

(b) Slab Shingle Tiles.

Lay slab shingle tiles with a 2-in. headlap and

secure each tile with two large-head roofing nails.

Double the tiles at the eaves and project them 1 inch

over the rear edge of gutters. Lay all tiles within 1

foot of hips, ridges, and abutting vertical surfaces

in roofer's cement. Lay 10- or 12-ln. tiles with 1-in.

headlap on sides of dormers. Match the tile courses

on dormer roofs with those on the main roof. Lay tile

roofs with open valleys.
- 83 -

4e8 Wood-Shingle Roofing

4,8*1 Description and General Discussion

Wood-shingle roofs are usually of red cedar, cypress or redwood shingles. Wood shingles are available

in three "Grades"; however, the description that follows applies only to the No. 1 grade.

Only heartwood should be used in making wood shingles, cut so that the annual or growth rings form an

angle no greater than 45° from the perpendicular when

a shingle is laid flat. This defines "edge-grain"

shingles and distinguishes them from flat-grain shingles

which are less resistant to splitting and warping than

the edge-grain shingles.

Thickness is the most important dimension of wood

shingles. It is measured at the butt ends and is

designated according to the number of pieces that are

necessary to constitute a specific unit of thickness.

Thus, 5/2 indicates that the butts of five shingles

measured together will give a total thickness of 2 in.

Wood shingles should be not less than l6 in, long.

Maximum width is l4 inches; minimum width of shingles

less than 24 inches long is 3 in, and for those 24 in,

long and longer, it is 4 inches.

Wood shingles are sold in bundles, with shingles

packed flat in courses, the butts of shingles in alternate courses facing in opposite directions, giving

a "square pack". The number of courses at each end

of a bundle are indicated so that a bundle designated

13/14 means one with 13 courses at one end and l4 at

the other. Each course of shingles in a bundle averages 18-1/2 "running inches", that is, the actual
- 84 -

width of the shingles in a course in a bundle. Given

this information and the desired exposure, it is easy

to calculate the number of bundles of shingles that

will be required to cover a square of roof surface.

The treatment of wood shingles with creosote preservative materially lengthens the life of a wood- shingle

roof. The creosote tends to exclude moisture; to prevent warping and splitting of the shingles; to retard

rot or decay and to decrease surface weathering. In

addition, shingle nails last longer with shingles that

have been given a creosote treatment.

Commercial Standard 31-52, "Wood Shingles (Red

Cedar, Tidewater Red Cypress, California Redwood)

issued by the Department of Commerce and available

from the Government Printing Office, discusses general

and detail requirements for No, 1 Grade wood shingles

and gives a glossary of terms used in connection with

wood shingles. Another reference is the "Certigrade

Handbook of Red Cedar Shingles", published by the Red

Cedar Shingle Bureau, Seattle, Washington,

4,8,2 Roof Decks for Wood-Shingle Roofs

Roof decks for wood- shingle roofs may be of solid

or open sheathing. Solid decks should be of wellseasoned sheathing lumber, nominal 1 in, in thickness,

either tongued-and-grooved or with straight sides, or

of plywood, exterior grade, not less than 1/2 in, thick.

When open or spaced sheathing is used the sheathing

boards (1 by 3 5 1 by 4 or 1 by 6 -in,) are spaced the

same distance as the anticipated shingle exposure and
- 85 -

each course of shingles is nailed to a separate sheathing

board; or 1 by 6-in, boards are spaced twice the distance

of the anticipated shingle exposure. By the latter method,

two courses of shingles are nailed to each sheathing board.

No underlay material is required for wood shingles,

^,8.3 Storage and Handling of Wood Shingles

Wood shingles should preferably be stored under cover

to maintain a uniform moisture content. If outdoor

storage is necessary, bundles should be piled on planks

to prevent contact with the ground and they should be

covered to protect them from the weather.

4.8,^ Determining Treatment for Wood-Shingle Roofs

Wood- shingle roofs of good quality shingles applied

correctly normally render long and satisfactory service.

Failures in wood- shingle roofs usually occur because of

warping or splitting of the shingles, decay, normal

weathering, or failure of the shingle nails.

Warping and splitting are found most frequently

with flat-grain shingles. They occur usually on the

portion of the shingle that is exposed to the weather.

Neither warping or splitting is likely to affect the

waterproofness of the roof because a wood- shingle roof

should have three layers of shingles throughout. Splits

in shingles, however, may shorten the life of a roof by

permitting water to reach the nails in the shingles

underneath and hasten their deterioration.
86 -

Decay in wood is caused by minute organisms that

thrive best in moist wood. Therefore, it is found most

frequently in low-pitched and shaded roofs that remain

moist for long periods.

Normal weathering proceeds slowly in wood shingles.

Factors in normal weathering are wind-driven rain, snow,

hail, or sand and alternate freezing and thawing in

winter. Very old wood- shingle roofs usually show the

exposed shingle butt just below the area protected by

the overlying shingle much thinner than the protected

area.

Failure of shingle nails is most frequently caused

by the splitting of shingles or the improper placement

of nails.

The effects of all of the deteriorating factors

mentioned are lessened appreciably by impregnating

the shingles with creosote oil. Impregnation by

(lipping or by pressure process before the shingles

are applied is much more effective than treatment

after application.

Maintenance and repair work for wood- shingle roofs

will be treated under the same heading.

4.8.5 Maintenance and Repair Methods - Wood-Shingle Roofs

A. Warped Shingles,

Warped shingles do not usually cause leaks and,

except for appearance, are not immediately objectionable.

Warped shingles will probably crack eventually, in which
- 87 -

case they should be removed. Warped shingles should

never be face nailed except in preparation for reroofing.

The nailing is likely to crack the shingles and the

nails will work loose, permitting the roof to leak.

B. Removing Cracked or Rotted Shingles and Applying

New Ones.

Broken wood shingles can be removed by the methods

described for removing broken slates (Section ^.6,5-A,),

except that at least four nails must be cut. After the

broken shingle is removed, insert a new one of the

same size and nail it through the exposed butt, preferably with thin copper nails. Also nail the shingle

immediately above through the exposed butt.

C. Treating Shingles with Creosote or Shingle Stain.

Wood-Preservative, Coal-Tar-Creosote, Crystal-Free,

for Brush, Spray or Open-Tank Treatment, under Federal

Specification TT-W-560, is an excellent preservative

for wood- shingle roofs. Application by brush, while

more laborious, is likely to be more effective than

application by spray because of better penetration.

If a colored roof is desired, pigmented stains

containing creosote oil or its derivatives should be

used in preference to those without creosote.

The frequency of treatment varies with the kind

of wood, pitch of the roof and any pre-treatment the

shingles may have been given prior to application.
- 88 -

Drying-oil paints should not be used on wood- shingle

roofs because unequal absorption and subsequent drying

of the paint may cause the shingles to warp and curl.

4,8.6 Reroofing with Wood Shingles

Wood shingles may be used for reroofing over woodand asphalt- shingle roofs and over smooth- and mineralsurfaced asphalt roofing. However, as with other materials, the better practice is to remove the existing

roof covering.

No attempt should be made to apply wood shingles

over metal, slate or asbestos-cement roofs because of

difficulties in nailing.

A, Preparing Deck for Reroofing with Wood Shingles,

(1) When Existing Roofing is Removed

Proceed as described under Section 4.2.6-A., "Preparing Deck for Reroofing with Asphalt Shingles", (1)

"When Existing Roofing Is Removed",

(2) When Existing Roofing Remains,

(a) Reroofing Over Wood Shingles.

Remove all loose and protruding nails. Replace decayed or missing shingles with new ones. Nail down or

cut off corners of curled and warped shingles and reanil loose shingles.

Cut back shingles at eaves and rakes far enough

to apply 1- by 4- in. strips securely nailed.
- 89 -

Remove weathered shingles at the ridge and replace

them with a strip of beveled siding, thin edge down, to

provide a solid base for nailing the ridge shingles.

Treat hips the same as ridges.

Fill open valleys with wooden strips level with the

shingle surface.

Install new non-ferrous metal vhlley flashings.

Install new non-ferrous metal base and counter

flashings, in accordance with new construction specifications, where necessary. Sweep all loose debris

from the roof deck.

(b) Reroofing Over Asphalt Roll Roofing.

Inspect carefully all sheathing boards at the eaves

and replace rotted boards with new ones.

Remove all loose or protruding nails. Cut all

blisters and buckles and nail cut edges to the roof

deck as illustrated in Figure

Repaint ferrous metal flashings that are in good

condition.

Install new non-ferrous metal base flashings and

new metal counter flashings in accordance with new construction specifications, where necessary.

Install new non-ferrous metal valley flashings.

Sweep all loose debris from the roof.
- 90 -

(c) Reroof Ing Over Asphalt Shingles.

Proceed as described in (b). Reroofing Over Asphalt

Roll Roofing and and in addition, nail down or cut away

the butts of all curled or lifted shingles.

B. Applying Wood Shingle Roof.

Apply a double course of wood shingles at the eaves,

with the butts of the shingles overhanging the eaves

1-1/2 in. Space all shingles in the same course 1/4 in.

and nail each shingle in these and subsequent courses

with two nails placed 1 to 1-1/2 in. above the butt

line of the succeeding course of shingles and not more

than 3/4 in. from the edge of the shingle on each side.

Break the joints between the shingles in successive

courses at least 1-1/2 in, and apply the shingles so

that the joints in alternate courses are not in line.

The exposure of wood shingles depends on the

slope of the roof and on the length of the shingles.

For slopes of 5 in. per foot and greater, the standard

exposures are as follows:

Length of shingle, in.

16

18

24

Exposure, in.

5

5-1/2

7-1/2

For slopes less than 5 in.

should be 3-3/4, 4-1/4 and

per ft., these exposures

5-3/4 in. respectively.
- 91 -

Use only hot-dipped galvanized nails, either round or

square cut, for applying wood shingles. Use 1-1/^ in.

nails for l6- and l8-in. shingles and 1-1/2-in. nails for

2*+-in. shingles in new construction. When wood shingles

are applied over an existing roof, use 1-3/^-in. nails

for 16- and l8-in. shingles and 2-in. nails for 24-in.

shingles. Nail heads should not be driven into the wood.

5. FLASHINGS AND APPURTENANCES

5.1 Wall, Chimney and Monitor Flashings

5.1.1 General Discussion

The function of a flashing is to provide a water-tight

junction between the roofing material and other parts of

the structure, and between roof sections. Flashings may

be defined as the most vulnerable part of any roof since

the majority of leaks result from failures at these vital

areas. There are numerous causes of flashing failures,

the most common resulting from inadequate or faulty construction, Many roof and flashing failures could be eliminated by constant and painstaking inspection by competent

inspectors during installation. Some common causes of

flashing failures are:

1. Weathering resulting from insufficient or lack

of protective coating,

2, Punctures usually resulting from the omission of

a cant strip. (Figure 42.;

3. Open laps or seams.

4, Separation of flasliing from vertical surface.

(Figure 11.)
92 -

5o No allowance made for expansion and contraction

. of metal flashing s*

In many instances, leaks have been attributed bo flashing failures where no such failures were evident* The

actual cause may result from open joints in a masonry wall

or chimney, into which the water enters, works its way

down behind the flashing and into the roofing* In masonry

walls, this condition may be eliminated by "through the

wall" flashings*

Flashings may be differentiated into two main classes,

namely, base and cap or counter flashing*

The base flashing is the actual junction between the

roofing material and the vertical wall, projection, etc*,

and should be considered as a component part of the roof

construction* The base flashing may be either of plastic

or metallic construction* For the purpose of this

manual, th,e term plastic flashing includes all types

other than metal.

The cap or counter flashing is usually constructed

of metal and serves as a protecting 'cover for the base

flashing* This flashing should extend a minimum of 8

in* and a maximum of 12 in, above the roof line and

should be set into a regie t extending into the wall at

least 4 in*

,

although through-wall flashings are preferable* The function of the cap or counter flashing is

to overlap the base flashing so that all flashing strips

and nails are completely covered. In some instances, a

cap flashing of felt or fabric is employed. This system

usually consists of a 4 to 6 in, strip of saturated felt

or fabric, embedded in plastic cement and placed 2 to 3

in* above and 2 to 3 in, below the top edge of the base
- 93 -

flashing so that all nail heads are completely covered.

A uniform coating of a plastic flashing cement is then

troweled to a feather edge over the felt or fabric strip,

5.1.2 Inspection Procedures

For convenience, the inspection form for flashings

is incorporated with the inspection forms for various

types of roofing in Appendix I.

A. Plastic Base Flashings.

A thorough inspection of flashings, at least once

every year, is essential since numerous failures attributed to the roofing material are frequently flashing

failures. These areas should also be the first to be

inspected when leaks are reported in a structure. A

good procedure to follow is to first make a careful inspection of the roofing material near the flashings for

signs of moisture. In built-up roofs, blisters in this

area are a sure indication that moisture has found its

way beneath the membrane. If blisters are evident and

the membrane seems intact, a flashing failure, however

small, is indicated. Following the inspection of the

roofing material, the entire base flashing should be

inspected for punctures, broken laps or seams, separation

of flashing from vertical surfaces and signs of deterioration. If a cant strip is present, it can usually be detected by gently tapping the flashing in the area mid-way

between the roof and the vertical surface with a solid

object. The areas in question should be clearly marked

for future maintenance and repair.
- 9^ -

B. Metal Base Flashings.

The common failures which occur in a metal base flashing are cracks, broken joints, and deterioration of ferrous

metal flashing due to lack of paint. The inspector should

pay particular attention to exterior and interior corners,

which areas are most vulnerable. Usually no cant strip is

employed when base flashing is of metal. The inspection

procedure is similar to that described under plastic base

flashings.

G, Plastic Cap or Counter Flashings.

During the inspection of plastic cap flashings, the

most likely causes of failure will be;

1. Separation of flashing from the vertical surface

and/or from base flashing.

2. Deterioration due to lack of protective coating,

D. Metal Cap or Counter Flashings.

The common failures in metal cap flashings are;

1. Location of the flashing too high or too low

above the roof deck.

2. Deterioration of ferrous base flashings due to

lack of paint,

3. Cracks and broken joints due to expansion and

contraction.

ho Separation of the flashing from the vertical

surface

,
- 95 -

5.1.3 Maintenance and Repair Methods

In the case of flashings, no definite distinction

can be drawn between maintenance and repair methods. Consequently, the two are combined in this section.

A. Plastic Base Flashings.

(1) Punctures. (Figure ^2.)

Punctures are usually caused by traffic or by falling objects striking a base flashing where a cant strip

has been omitted.

Treatment : For temporary repair, make puncture watertight by coating with plastic flashing cement and embedding into the cement a saturated felt or fabric, following

with a trowel coat of plastic flashing cement.

For permanent repair, remove the broken flashing,

install a cant strip and reflash in accordance with

standard specifications for new roof construction.

(2) Vertical Laps of Flashing Open,

Treatment : Smooth laps back in place and re-cement

with plastic flashing cement. Recoat entire lap with

plastic flashing cement.

(3) Separation or Sagging of Base Flashing from

Wall, Chimney or Monitor,

Treatment ; Refasten the base flashing to the vertical surface by nailing or cementing. Recoat with a plastic flashing cement and replace appropriate counter

flashing.
- 96 -

(4) Surface Coating of Plastic Base Flashing

Disintegrated

.

Treatment : Brush off all loosely adhering coating and

apply a trowel coating of asphalt or coal-tar plastic

cement as used for the original coating.

B, Metal Base Flashings.

(1) Lack of Protective Coating of Paint. Metal

Not Severely Deteriorated.

Treatment ; Remove all rust, moisture, loose scale,

grease, dirt, etc., and apply fresh coating of paint.

Instructions for painting metal are given In current

publications.

(2) Lack of Protective Coating of Paint. Metal

Severely Deteriorated, l.e.. Holes, Punctures, Etc.

Treatment ; Remove and discard deteriorated area of

flashings and re-flash In accordance with standard specifications for new roof construction.

(3) Vertical Joints of Base Flashing Open.

Treatment ; Straighten the metal flashing and put

It In place. Re- solder open joints. Install additional

expansion joints where necessary.

(4) Separation of Metal Base Flashing from Wall,

Chimney or Monitor.

Treatment ! Treat as described under maintenance and

repair of plastic base flashings.
97 -

C. Plastic Cap or Counter Flashings,

(1) Separation of Plastic Cap Flashing from Vertical

Wall and/or Base Flashing.

Treatment : Re-cement plastic cap flashing with a plastic flashing cement and apply a trowel coat of flashing

cement

(2) Deterioration Due to Lack of Protective Coating.

Treatment : Brush off all loosely adhering coating

and apply a trowel coating of plastic flashing cement.

D. Metal Cap Flashings.

(1) Lack of Protective Coating of Paint. Metal Not

Severely Deteriorated,

Treatment : As described under maintenance and repair

of metal base flashings,

(2) Lack of Protective Coating of Paint, Metal

Severely Deteriorated,

Treatment : As described under maintenance and repair

of metal base flashings.

( 3 ) Metal Cap Flashing Located Too High or Too Low

to Function Properly,

Treatment : Remove the loose flashing and trim off

flush with the wall any flashing metal left in the

joint. Make necessary repairs to the vertical surface

and re-flash in accordance with standard specifications

for new roof construction into a new reglet at least

2 in. above the old one.
- 98 -

E, Repair Methods of Flashings When Repairs Involve .. Application of a New Membrane,

Treatment s Remove existing flashing and cut old membrane flush with base of vertical surface. An exception

may be made with the metal counter flashing that is in

good condition, well fastened to the wall, and which will

stand bending up for the application of new base flashing and bending down after base flashing is installed.

Install new base flashing after repair membrane is

applied in accordance with standard specifications for

new roof construction,

F. Repair Methods for Parapet Walls,

Note s It is poor practice to coat parapet or fire

walls with an impervious coating,

(1) Mortar Joints Deteriorated,

Treatment s Rake out all loose mortar and repoint

with a 1:1:6, portland cement, hydrated lime and sand

mortar, proportioned by volume.

(2) Joints in Coping Open,

Treatment : Rake out all loose material and repoint

with Portland cement or a caulking compound complying

with Federal Specification TT-C-598,

9»2 Vent Flashings

9«2.1 General Discussion

The majority of vents are constructed of metal and

consequently are subject to expansion and contraction.

For this reason, it is poor practice to attempt to

flash up the sides of such projections as this type of

flashing is subject to early failure. Vents are usually
99 -

of two types, namely ^ the flat flange vent and the curb

vent. The former being the most common. The flat flange

vent is placed directly upon the last ply of roofing

while the curb vent is constructed to fit over a wooden

or concrete curb. Each type is supplied with a component flashing flange by which the vent is connected to

the roofing. In the case of the flange vent, asphalt,

pitch, or plastic cement is used generously beneath and

above the metal flashing flange which is securely nailed

to the roof. The flange is stripped with two plies of

felt, not less than double the width of the flange,

cemented solidly together and to the flashing flange

with asphalt, pitch or plastic cement. The flashing

flange of the curb vent is secured to the curb after

the flashing is brought up and over the curb,

5.2.2 Inspection

All vents and vent flashings should be carefully

inspected during the periodic roof inspection and at

such times that leaks are reported in the structure.

An inspection should also be made from the underside

of the roof. Damp areas or stains near the vent indicate a flashing failure. Common failures to

in vents and vent flashings are:

look for

(1) Broken seams caused by expansion and

traction.

con-

(2) Exposed nails that have worked loose causing

separation of metal flashing flange from

roof (Figure 43).

(3) Omission of felt stripping over edge

flange

,

of

(4) Standing water around vent or stains

jacent roofing (Figure 44).

on ad-

(5) Deterioration of metal caused by lack of

protective coating of paint.
- 100 -

5o2c3 Maintenance

A, Broken Seams Caused by Expansion and Contraction,

Treatment ; Re- solder broken seams and install additional expansion joints if necessary,

B, Separation of Flashing Flange from Roof Caused

by Exposed Nails Working Loose (Figure 43),

Treatment ; Raise flashing flange high enough to

force plastic cement beneath it and redrive loose

nails. Apply two plies of felt or fabric cemented

to each other and to the flange with asphalt, pitch,

or plastic cement. The outer edge of the first ply

of felt or fabric should extend not less than 3 in.

beyond the flange and of the second 'ply of felt or

fabric not less than 6 in. Apply finished surfacing

similar to roof surfacing,

C, Omission of Felt Stripping Over Flashing Flange,

Treatment ; Treat edges by applying two layers of

felt or fabric as described in B, above,

D, Standing Water Around Vent or Water Stains on

Adjacent Roofing (Figure ^4),

Treatment ; (Treat only if leakage occurs,) Remove

old flashing and reflash in accordance with instructions given in B, above.

In severe cases re-installation of the vent may

be called for.

E, Lack of Protective Coating of Paint With or Without Deterioration of Metal,

Treatment ; Remove all rust, moisture, loose scale,

grease, dirt, etc,, and apply fresh application of
101

paint. Instruction for painting metals are given in

current publications.

In cases where metal is seriously deteriorated,

removal and replacement with new vent may be called

for,

5.2.4 Repair During Reroofing

Metal vents and the flashing flanges should be

carefully inspected for signs of deterioration. If

deterioration is serious, remove old vent and install

new vent in accordance with standard specifications

for new roof construction.

If the present vent is deemed serviceable, proceed as follows:

1) Flange vent - If the flashing flange is

securely fastened to the old roof, the new membrane

should be cut to fit around the vent and applied

over the flashing flange.

2) Curb vents - Raise the vent and re-flash so

that the new flashing can be brought up and over the

curb and replace and refasten vent to the curb.

5.3 Valley Flashings

5.3.1 General Discussion

Roof valleys are formed when two sloping roof

sections join to form a V. Since water from both

sections is concentrated in the valley, valley
- 102

flashings are of extreme importance.

Valley flashings on tile, slate asbestos-cement

shingles, wood shingles, metal and similar roofs are

usually constructed of metal, while those on mineralsurfaced asphalt roll roofing and asphalt shingles are

constructed either of metal or mineral-surfaced roll

roofing. Valleys on smooth- surfaced roll roofing

roofs are usually of smooth- surf aced roll roofing.

A, Metal Valley Flashings.

Metal valley flashings may be of 20-ounce copper

or similar material and are applied in sheets not exceeding 8 ft. in length, free from longitudinal seams

and of sufficient width to extend not less than h in.

under the roof covering on each side. The exposed

portion is approximately 4 in. wide at the top and

increases 1 in. in width for each additional 8 ft.

in length. Each section is lapped not less than 6 in.

(8 in. where the slope of the valley is less than

4-1/2 in. per foot) in the direction of flow and the

upper end is fastened to the roof deck.

With slate or tile roofing, 24-oz. copper is

generally used in place of the 20-oz. , and where

valleys are installed with clay or cement tiles, the

exposed valleys have a uniform width of 4 in. in

place of the increasing width of 1 inch per 8 feet.
- 103 -

B, Mineral-Surfaced Asphalt Roll Roofing Valley

Flashings.

Mineral- surf aced asphalt roll roofing is satisfactory for flashing valleys of both asphalt- shingle and

mineral- surfaced asphalt roll roofing roofs. The valley

is lined with two thicknesses of the material. The

first ply is l8 in, in width and centered in the valley

with surfaced side down. The second ply, 38 in. in

width, is applied over the first strip, centered into

the valley, nailed and cemented with surfaced side up.

The width of the Valley is 6 to 8 in. wide at the top

and will diverge at the rate of 1 inch per each 8 feet

of the valley.

5.3.2 Inspection

Valleys must be kept clean to function properly.

Ice dams and debris blocking valleys may cause water

to back up beneath the roofing or laps of the valley.

The valley incline should be checked for smoothness

and uniformity to assure a rapid run-off of the water.

A. Metal Valleys,

Copper valley flashings usually require little

maintenance if properly installed, while terne and

galvanized valleys should be inspected for lack of

paint and signs of rust. The inspector should look for

separations at the end laps and for openings in the

metal due to corrosion.

B. Mineral-Surfaced Roll Roofing Valley Flashings,

The inspector should look for signs of normal

weathering which will most likely appear in this area

first since water concentrates in the valley. The
- 10^ -

first indication is the loss of granules, slight at

first, but accelerating as the loss of granules exposes

mor of the asphalt to the weather » Separation of end

laps and separation of the roof proper from the valley

flashings often result in leaks*

5*3 *3 Maintenance and Repair

Ao Metal Valley Flashings.

Valleys must be kept clean to function .

(1) Leakage Occurring at Laps,

Treatment ; Do not attempt to solder laps. Treat

seam or lap with a white lead paste consisting of basic

lead carbonate and 8^ boiled linseed oil,

(2) Small Holes in Copper Flashings,

Treatment : Clean surface around hole with emery

cloth, apply a flux of zinc chloride or rosin and repair with a drop of solder,

(3) Large Holes in Copper Flashings,

Treatment ; Prepare surface as in (2) above and solder

a piece of copper over the hole,

(4-) Holes in Galvanized Metal Flashings.

Treatment ; Replace the smallest unit of the flashing.
- 105 -

(5) Lack of Protective Coating of Paint on Terne or

Galvanized Metal Valleys*

Treatment s Painting should never be put off until rust

appear So Should rust appear, remove all rust, moisture

loose scale, grease, dirt, etc., and apply new application

of paint. Instructions for painting metals are given in

current publications«

B. Mineral-Surfaced Roll Roofing Valley Flashings.

Valley must be kept clean to function properly .

(1) Loss of Granules Due to Normal Weathering and

Water Concentrating in Valley.

Treatment ; Remove all loose granules, dust, and dirt

by sweeping, vacuuming or air blast and apply one thin

coat, by brushing, of asphalt primer (SS-A-701). After

primer is dry, apply one of the followings 1) a coating

of asphalt emulsion (MIL-R-3^72) by brush at a rate

of 3 gallons per square 5 2) Asphalt-base roof coating

meeting Federal Specification SS-R-^5l> by brush, at a

rate of 3 gallons per square 5 3) Fatty-acid-pitch base

roof coating at a rate of 3 gallons per square, available in natural, green, buff, or red colors.

(2) Separation of End Laps.

Treatment ; Lift upper lap high enough to force a

liberal amount of plastic cement between plies and

press top lap firmly in place.
- 106 -

(3) Separation of Roofing or Shingles from Flashing,

Treatment ; Gently lift separated shingle or area,

force plastic cement beneath it, and press shingle or

roofing firmly into the cement.

5.^ Drainage Systems

5A.1 General Discussion

The drainage system includes all gutters, leaders,

drains, scuppers, crickets, etc. The primary function

of this system is to remove water from a roof as quickly

as possible and to prevent the storage of water on the

roof. Every roof must have some provision for drainage,

including the so-called "dead-level" decks. It is

important that drainage areas be kept free from debris

which will interfere with proper drainage (Figure 45).

Many roof failures can be traced both directly and

indirectly to inadequately designed or improperly installed drainage systems.

5.4,2 Inspection

A suggested check list for inspectors is as

follows:

1) Check deck incline. It should be smooth and

uniform.

2) Look for low areas. Standing water or water

stains are signs of low areas.

3) Check gutters, leaders, etc., for obstructions

which will hinder the run-off of water.
- 107 -

Check size, locations and number of drains,

gutters and leaders.

5) Look for broken or clogged drains.

6) Look for standing water around drains. This

indicates drain is set too high or not in

correct location.

7) Look for defective flashing around drains.

Drains are usually equipped with a flashing

flange which should be securely fastened to

the roof deck and double felt stripped as in

the case of vent flashings.

8) Check gutters for defective hangers and straps.

9) Check gutters for holes, rust or other signs of

deterioration.

5.^.3 Maintenance and Repair

A. Drains.

Must be kept clean to function properly (Figure

^6 ).

(1) Broken Drains,

Treatment ; Remove broken drain and install new

drain in accordance with specification of new roof

construction.
- 108 -

(2) Separation of Flashing Flange from Roofo

Treatment ; As described in Section

(3) Standing Water Around Drain,

If drain is clean, this condition indicates drain is

not at a low point of the area or is set too high.

Treatment ; Re-install or re-locate the drain,

B, Gutters and Leaders,

Must be kept clean to function properly ,

(1) Rusting or Corrosion of Gutters and Lead'Sr's.

Treatment ; 1) Metal not deteriorated ; Remove all

rust, moisture, loose scale, grease, dirt, etc,, and

apply new coat of paint. Instructions for painting

metals are given in current publications,

2) Metal severely deteriorated ; Remove defective

section and replace with new material in accordance

with standard specications for new roof construction,

(2) Defective Straps and Hangers,

Treatment ; Replace and re-align defective straps

and hangers,

C, Low Areas, Permitting Water to Stand (Figure

Failures of this type are usually the result of

poor design or structural failure. Building up the

roof covering with felt and hot bitumen or any type
- 109 -

of fill is not recommended since the materials only

add weight to an already weakened area*

Treatment ; Before repair or re-rooflng is started,

the low area should he corrected by raising the sunken

joists or installing new joists. Where little can be

done to correct such a failure, the relocation of the

drain to the low area will be of value,

5.5 Gravel Stops and Metal Edge Strips

5,5»1 General Discussion

The primary function of gravel stops (slag or

gravel surfaced roofs) and metal edge strips (smoothsurfaced built-up roofs) is to finish off all exposed

edges and eaves in order to prevent wind from getting

under the edges causing blow-offs. Another important

function of the gravel stop is to prevent the loss of

gravel or slag from areas near the edge of the roof.

The flashing flange of the gravel stop or edge strip

is placed over the last ply of felt and should extend

at least h inches on the roof. It should be nailed

securely to the roof deck and double felt stripped,

after which the finished coat of bitumen and surfacing

or cap sheet is applied. The lip of the gravel stop

should protrude a minimum of 3/^ inch above the roof

deck while the lip of the edge strip should be a maximum

of 1/2 inch above the deck. Both should be securely

fastened to the facia board.

Many structures have been observed where gravel

stops or edge strips have been omitted. In lieu of

this practice, the roofing membrane was bent over the

V
110

edge and fastened to the facia board with wooden battens

as shown in Figure 48. Figure 49 shows a section of

this roof after repair and the installation of a metal

gravel stop*

Numerous failures or potential failures have occurred

at these vital areas due to severe weathering of the roofing material and to the deterioration of the wood battens

and the facia boards which in turn renders the roof membrane susceptible to wind damage

o

Inspection

The gravel stops and edge strips should be inspected

during the annual inspection of the roof. The inspector

should examine carefully the entire edge of the roof,

paying particular attention tos

1 ) Rotted or rusted gravel stops and edge strips,

2 ) Damaged or rotted overhangs and facia boards,

3) Separation of flashing flange from the roof,

4) Bitumen flowing under gravel stop and down

facia board,

9) Omission of gravel stops and edge strips^
Ill

5.5«3 Maintenance and Repair

Ao Rotted or Rusted Gravel Stops and Edge Strips,

Treatment ; Not Seriously Deteriorated - Remove all

rust, moisture, loose scale, grease, dirt, etc,, and

apply fresh coating of paint to ferrous metal. Instructions for painting ferrous metals are given in current

publications

,

Seriously Deteriorated - Remove and discard section

containing deteriorated area and replace in accordance

with standard specifications for new roof construction

after damaged overhang and facia boards are repaired

or replaced with new ones,

B, Damaged, Rotted or Deteriorated Facia Boards and/or

Overhangs.

Treatment : Remove and discard all deteriorated metal.

Repair and replace facia boards and overhangs and install

new gravel stop or edge strips in accordance with standard

specifications for new roof construction,

C. Separation of Flashing Flange from Roof Membrane,

Treatment ; Scrape off gravel or slag at least 12

inches from gravel stop and lift flange high enough to

force plastic cement beneath it. Re-nail in place and

apply two layers of felt stripping, the top one overlapping the lower one 2 to 3 inches. Pour hot bitumen

over bare area and while hot, embed clean, dry slag or

gravel as used for the roof.
112

D. Bitumen Flowing Beneath Gravel Stop and Down Facia

Boards.

This type of failure, more common in the coal-tar

pitch roof, is usually due to original design or construction and very little can be done to correct it

after installation of the roof. However, it can be

prevented by a simple means, by Installing the roof

as follows:

1) Extend the first two plies of felt at least

6 inches beyond the edge of the roof,

2) Cut the next 2 or 3 plies even with the edge,

3) Turn the extension of the first two plies back

and over the other plies forming an envelope,

h) Install gravel stop in usual manner over this.

E, Omission of Metal Gravel Stop or Metal Edge Strip,

Treatment ; These areas should be inspected at frequent intervals (every 6 months) and at first indication of failure, gravel stops or metal edge strips

should be installed in accordance with standard specifications for new roof construction. This practice

will prevent costly blow-offs.
- 113 -

5o6 Other Projections 5.6.1

General Discussion

The projections included in this section are pipes,

stacks, ladder struts, flag poles, bracings for signs,

etc,, which penetrate the roofing. No attempt should

be made to flash around these projections with felts,

as any expansion, contraction or other movement in

these members will crack the felts and a leak will

develop. All such projections should be flashed with

a metal sleeve flashing with flange or, on built-up

roofs, a pitch pocket with flange (Figure 50).

5.6.2

Inspection

The flashing at the projections should be inspected

during the periodic inspection,

5,6,3

Maintenance and Repair

A, Defective Flashings at Projections.

Treatment : Cut away old felt flashings and install

a metal sleeve flashing with flange or a pitch pocket

with flange. The flashing flange should be placed on

the last ply of felt and securely nailed and cemented to

it. The flange then should be stripped with two layers

of felt, the top one overlapping the bottom one by 2 to

3 inches, and cemented with hot bitumen. In the case of

the pitch pocket, the cup is filled with hot bitumen.

On wood decks, a layer of concrete, one inch in thickness,

is poured in the pitch pocket and allowed to set prior

to the hot bitumen.
- 114 -

6, SAFETY MEASURES

6.1 General Discussion

Construction work generally is inherently hazardous.

Roof work, whether it be new construction, maintenance or

repair, because of its nature, ranks high in the incidence

of accidents. While it is true that accidents may occur

in spite of measures taken to prevent them, a well-defined

program to prevent accidents always pays dividends.

Accident prevention is closely tied in with efficiency.

The contractor whose equipment is always in order; who

attempts to predetermine the hazards of each particular

project and plans accordingly for the prevention of accidents, will not only encounter fewer accidents, but will

also operate more efficiently.

While this is not intended to be a complete manual on

safety precautions in roofing, observance of the following

suggestions will go far to prevent common accidents.

Good reference works on safety in the construction

field are:

"Manual of Accident Prevention in Construction", published by the Associated General Contractors of America,

Inc., Munsey Building, Washington 4, D. C.

"American Standard Safety Code for Building Construction", A.S.A. AlO. 2-1944, published by the American

Standards Association, 70 E. Forty-Fifth Street, New York

17, N. Y,
- 115 -

6o2 Storage and Handling of Materials

Segregate materials as to kind and size and place them

in neat, orderly piles that are safe against falling. (See

instructions under each type of roofing material.

Place warning signs in daytime and red lights on and

around materials stored in walkways or streets at night.

6,3 Ladders

Test all ladders to determine whether they are strong

enough to carry the intended loads.

Construct wood ladders of straight-grained materials

free from defects. Avoid painted ladders since the paint

may serve to conceal defects,

Mark metal ladders with signs cautioning against use

around electrical equipment.

Provide ladders with non-slip bases and fasten at

the top when possible.

Place the foot of a Ivadder not more than one-fourth

its length away from the vertical plane of its top support , Extend ladders leading to landings or walkways at

least 36 in, above the landing and fasten so that they

cannot slip. Avoid splicing ladders whenever it is

possible.

Construct "chicken" ladders or crawling boards at

least 10 in, wide and 1 in, thick, to which are nailed

cleats, 1-1/2 in. wide and 1 in. thick, extending the

width of the board.
- 116 -

The board should extend the full length from the ridge

to the eaves and should be fastened securely to the ridge

so that it cannot become loose.

Make each section of double boards as a single board,

with the two sections hinged or bolted together. Use

double boards with the sections straddling the roof, with

the hinge bolt resting on the ridgepole.

Provide a catch platform or life line on roofs pitched

more than 3 in, per foot.

6,4 Scaffolds

Design scaffolds to take the maximum loads to which

they will be subjected.

Protect the edges of all scaffolds with railings and

toe boards.

Do not use scaffolds for the storage of material except that being used currently. Clean scaffolds dally

of all rubbish.

6,5 Roof Brackets

Form triangular roof brackets from three pieces of

2 by 4 in, lumber, with the diagonal member sloped to

match the pitch of the roof, and the horizontal member

level to support the roof plank.

Support roof brackets by ropes fastened to a hook

securely hooked over the ridgepole of the roof, or to

roof members on the other slope of the roof, or by

means of pointed projectors driven their full length

into the roof framing or deck.
- 117 -

Provide a catch or scaffold platform, extending at

least 2 fto beyond the eaves and equipped with a guard

rail, on roofs without parapet walls, where the slope is

greater than 3 in„ per foot and the distance from ground

to eaves is more than 20 feeto A life line of manila

rope securely fastened to a safe anchorage may be substituted for the platform*

6*6 Heating and Handling Bituminous Materials

Mount heating kettles on firm, level, non-combustible

foundations* Keep them at least 3 feet from any combustible materials, and keep one or more suitable fire extinguishers within 50 feet of each kettle* See that

kettles in use are constantly attended and adequately

protected from personnel, vehicles, and other equipment*

Provide each kettle with a close-fitting lid which

can be closed at once if the heated material flames* A

temperature-recording device to help prevent material

from being heated above safe temperatures should also

be used*

Material must be thoroughly dry before it is added

to heated contents of kettles* Add material by sliding

it into kettles, not by dropping it*

Do not add any inflammable substance to thin or

dilute material being heated* Shut down kettle burners

when refueling, and if heated material bursts into

flame*

In handling hot substances, use hoisting gear heavy

enough for the loads imposed* Brace all gear securely*

In hoisting and handling hot substances, be careful not

to endanger workmen nearby or below*

Require all persons handling hot substances to use

proper foot and leg protection, gloves, goggles, and any

other necessary personal protective equipment*
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APPENDIX I

HISTORICAL RECORD FORMS

AND

INSPECTION FORMS
120 -

HISTORICAL RECORD - BUILT-UP ROOFS

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Kind of Roof Deck ; Wood Concrete slab Concrete

block Gypsum slab Gypsum plank Steel

Slope of Roof s Flat In. per foot

Area of Roof : Squares (one square equals 100 sq. ft.)

Type of Built-Up Roof s Asphalts Surfaced Unsurfaced _____ Cold process

Wide selvage

Coal-Tar Pitch

Kind of Surfacing ; Slag Gravel _____ Crushed stone

Promenade tile Slate slabs Mineral- surf aced cap

sheet Smooth- surfaced cap sheet Other surfacing

(name)

Number of Plies of Felt s 2 3 ^ 5

Kind of Felt ; Organic (Rag) Coated Uncoated

Asbestos Coated Uncoated

Insulation : Yes No Thickness

Type of insulation

Where placed

Vapor seal: Yes No Type of vapor seal
121 -

Flashings ; Base flashings; Metal Kind of metal

Composition Kind

Other (describe)

Counter or cap flashings; Yes No ______

Through wall; Yes No Metal Kind of

metal Composition Kind

Other (describe)

Flashing block; Yes No

Previous Maintenance ; (Describe briefly with dates*)

Roof membrane;

Flashings;

Previous Repairs ; (Describe briefly with dates.)

Roof membrane;

Flashings
HISTORICAL RECORD - ASPHALT -SHINGLE ROOFS

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Kind of Roof Deck : Sheathing boards Thickness, in^

S,S, T & G Plywood Thickness, inc

Underlayment ? None Saturated felt Paper Asphalt

shingles Wood shingles Other

Slope of Roof, in. per ft p Area of roof, squares

Type of shingles ; Strip shingles Exposure, in^

Individual shingles Exposure, in.

Strip shingles; Square butt Hexagonal

Square butt shingles; Thick butt Standard weight

Heavy weight Class A

Hexagonal shingles; Standard weight Heavy weight

Individual shingles; Standard weight Heavy weight

Method of laying; American Dutch lap Hexagonal

Lock down Exposure, in.

Color of Roofing Granules ; Flashings ; Valley flashings; Roll roofing Asphalt shingles

Metal Kind of metal

Drip edge; Roll roofing Asphalt shingles Metal

Kind of metal
123 -

Vent flashings: Roll roofing Metal Kind of metal

Chimney flashings: Roll roofing Metal Kind of

metal

Previous Maintenance: (Describe briefly with dateso)

Asphalt shingles:

Flashings:

Previous Repairs : (Describe briefly with dates,)

Asphalt shingles:

Flashings
- 124 -

HISTORICAL RECORD - ASPHALT ROLL-ROOFING ROOFS

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Kind of Roof Deck ; Sheathing boards T & G_ S,S.

Thickness, in. Plywood Thickness, in.

Underlayment : None Saturated felt Paper Asphalt

shingles Wood shingles Other

Slope of Roof. In/ft . Area of roof, squares

Type of Roll Roofing ; Mineral surfaced Smooth- surfaced

Wide selvage

Method of Laying s 2-in. lap 4-in. lap 19-in.

lap Concealed nails Exposed nails . Type of Lap Cement : Hot applied Cold applied

Color of Roofing Granules : Flashings : Valley flashings: Roll roofing Asphalt shingles

Metal Kind of metal

Drip edge: Roll roofing Asphalt shingles Metal

Kind of metal

Vent flashings: Roll roofing Metal Kind of

metal

Chimney flashings: Roll roofing Metal Kind of

metal
- 125 -

Previous Maintenance ; (Describe briefly with dates.)

Asphalt Roll Roofing:

Flashings:

Previous Repairs : (Describe briefly with dates.)

Asphalt Roll Roofing:

Flashings;
- 126 -

HISTORICAL RECORD - ASBESTOS -CEMENT ROOFS

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Type of Roof ; Corrugated sheets Shingles

Type of Shingle : Dutch lap Hexagonal

American Multiple Unit

Type of Deck ;*

Shingle: Wood Other

Corrugated: Wood Other

Purlin Spacing in.

Slope of Roof : in. per foot

Area of Roof : Squares (one square equals 100 sq.ft,)

Type of Underlayment : Asphalt-saturated asbestos felt Asphalt-saturated

organic felt Other

Weight of felt, lbs.

Kind of Fasteners : Shingles: Nails Other Size

Corrugated sheets: Clips Type

Screws Size Bolts Size

Nails Size Other Size
127 -

Flashings : Valley flashings: Metal Kind of Metal Other

Vent flashings: Metal Kind of jnetal Other

Drip edge: Metal Kind of metal

Chimney flashings: Metal Kind of metal

Other

Previous Maintenance : (Describe briefly with dates.)

Asbestos-cement roofing:

Flashings:

Previous Repairs : (Describe briefly with dates.)

Asbestos-cement roofing:

Flashings:
- 128 -

HISTORICAL RECORD - METAL ROOFING

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Kind of Roof Deck ; Wood Metal Other

Solid Open Purlins Purlin spacing in»

Slope of Roof ; ine/fto

Area of Roof

Squares (One square equals 100 sq^ft)

Kind of Metals Terne (tin) Wto coating

2 Copper Wt. ft» Galvanized steel Wto

coating Aluminum Gage Protected

metal Kind of protected metal

Type of Metal Roof ; Flat sheets Corrugated sheets

Special shapes Shingles or tiles

Type of Seams ; Batten Standing Other

Flat Soldered s Yes No

Type of Fasteners ; Nails Bolts Clips Screws_

Cleats Other

Flashings ! Valley flashings (describe)
- 129 -

Vent flashings (describe)

Chimney flashings (describe)

Previous Maintenance ; (Describe briefly with dates*)

Metal roofings

Flashings:

Previous Repairs ; (Describe briefly with dates*)

Metal roofing;

Flashings;
- 130 -

HISTORICAL RECORD - SLATE ROOFING

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Type of Slate : Approx» thickness, in,

Color of Slate ? Approx, wt, /square, lbs,

Slope of Roof ; in, per foot

Area of Roof ; Squares (One square equals 100 sq. ft.)

Roof Deck : Wood Thickness, in. Width, in.

Other (explain)

Under layment ; Asphalt- saturated asbestos felt

Weight Asphalt- saturated organic felt

Weight Other (explain)

Type of Fasteners ; Nails Size Other

Flashings : Valley flashings: Metal Kind of Metal Other

Vent flashings: Metal Kind of Metal Other

Drip Edge: Metal Kind of Metal

Chimney flashings: Metal Kind of Metal

Other
- 131 -

Previous Maintenance : (Describe briefly with dates„)

Slate roofing:

Flashings:

Previous Repairs ; (Describe briefly with dates,)

Slate roofing:

Flashing:
- 132 -

HISTORICAL RECORD - TILE ROOFING

NOTE ; For Promenade Tile on Flat Decks, Use Historical

Record for Built-Up Roofs,

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Type of Tile : Shingle Spanish Interlocking Other

Thickness in, Wt, per square

Color

Slope of Roof ; in. per square

Area of Roof : Squares (One square equals 100 sq.ft.)

Rood Deck s Wood ^Thickness, in. Width of sheathing

boards, in. Other

Underlayment ; Asphalt-saturated asbestos felt Weight

Asphalt-saturated organic felts Weight Other

(explain)

Type of Fasteners ; Nails Size Other

Flashings s Valley flashings; Metal Kind of Metal

Vent flashings: Metal Kind of Metal

Drip edge; Metal Kind of Metal

Other

Other
- 133

Chimney flashings: Metal Kind of Metal

Other

Previous Maintenance : (Describe briefly with dates.)

Tile roofing:

Flashings

Previous Repairs : (Describe briefly with dates.)

Tile roofing:

Flashing:
- 13 ^ -

HISTORICAL RECORD - WOOD-SHINGLE ROOFS

BUILDING USED FOR

Permanent Temporary Year Roof Was Applied

Kind of Rood Deck ? Sheathing boards; T & G S.S„

Thickness, in. Shingle lath: Width of spacing, in.

Thickness, in. Plywood; Thickness, in.

Underlayment ; None Saturated felt Paper Wood

shingles Asphalt roll roofing Asphalt shingles

Other

Slone of Roof. In/ft. Area of roof, squares

Kind of Shingles ; Cedar Cypress Pine Other

Thickness of Shingles ; h butts/2 in. ______ 5 butts/2 in.

Other, define

Exposure ; in. Shingles pre- stained: Yes NOo

Flashings ; Valley flashings; Metal Kind of Metal Wood

shingles Other

Vent flashings; Metal Kind of Metal Other

Drip edge; Metal Kind of Metal Wood

shingles Roll roofing

Chimney flashings; Metal Kind of Metal

Other
- 135 -

Previous Maintenance ; (Describe briefly with dates.)

Wood shingles:

Flashings

Previous Repair : (Describe briefly with dates.)

Wood shingles:

Flashings:
- 136 -

INSPECTION FORM: ANNUAL INSPECTION OF BUILT-UP ROOFS

BUILDING DATE OF INSPECTION

Roofing Membrane

General Appearance ; Good Fair Poor

Water Tightness : No leaks Leaks with long-continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of roofing material

Faulty material Faulty design Faulty construction Wind damage Hail damage Traffic

on roof Other mechanical damage (describe)

Low spots (water ponding) _______ Failure of flashings Failure of gravel

stops Other causes (describe)

IT

Adhestion of Mineral Surfacing to Bitumen: Good Fair

Poor

Bare Areas; (Give approximate percentage of total roof area

below.)

Bituminous coating exposed Condition of coating;

Smooth Alligatored Cracked Felts exposed

1/

Surfaced roofs only.
- 137 -

Felts disintegrated Edges of felts curled

Blisters (Give size range and approximate number per

square if numerous.)

Cracked to allow water to enter: Yes No

Buckles Cracked to allow water to enter: Yes No

Cracks in membrane _____ Through to roof deck: Yes No

Fishmouths

General Condition of Roof Membrane:

Treatment Recommended:

Flashings:

Base Flashings : Metal:

Deteriorated Vertical joints open Flanges of

base metal flashing loose: Yes No Due to:

Inadequate nailing Not properly sealed with felt

strips

Plastic

Sagged or separated from parapet wall Buckled

Cracked Failure of base flashing: Weathering

Mechanical Surface coating disintegrated: Yes _

No Vertical laps not cemented properly: Yes No
- 138 -

Cap Flashings : Metal:

Firmly embedded into vertical wall; Yes No

Deteriorated Vertical joints open Not covering

base flashing adequately; Yes No

Plastic

;

Surface coating disintegrated Flashing felt disintegrated

Flashing Block ; Groove pointed sufficiently; Yes No

Recommended Treatment;

Parapet Walls ; Mortar joints deteriorated Settlement cracks in

walls Joints in tile coping open ______ Concrete

coping cracked _____ Other defects (describe) _______

Recommended Treatment;

. l40 -

INSPECTION FORM; ANNUAL INSPECTION OF

ASPHALT -SHINGLE ROOFS

Note; Asphalt- sHlngle roofs should never he wakled upon

directly e When it is necessary to get on a roof, ladders

or boards with cleats nailed to them should be used to

distribute the weight,

BUILDING DATE OF INSPECTION

Asphalt Shingles

General Appearance ; Good Fair _______ Poor

Water Tightness ; No leaks ____ Leaks with long-continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of shingles ______ Faulty material Faulty design _____ Wind Damage

Faulty application; a. Nailed too high b. Too few

nails c. Exposure too great

Hail damage Traffic on roof Other mechanical

damage (describe) ________________________________________________________ Failure of flashings Other causes (describe)

Condition of Shingles ; Apparently unchanged Buckled

Blistered Loss of Granules; Slight Medium

Severe (bare areas) Curled ______ Tabs Missing

Asphalt coating damaged (hall, etc,) Coating alligatored

or cracked Other defects (describe)
- l4l -

General Condition of Asphalt-Shingle Roof ;

Treatment Recommended

Flashings : (Describe condition if defectiveo)

Chimney Flashings: Satisfactory Defective

Wall ” : Satisfactory Defective

Ridge " : Satisfactory _______ Defective

Vent " : Satisfactory Defective

Valley " ; Satisfactory Defective

Edge " : Satisfactory ________ Defective

Drainage System : (Describe condition if defectiveo)

Gutters: Satisfactory Defective

Downspouts; Satisfactory Defective

Treatment Recommended
- li+2 -

INSPECTION FORM; ANNUAL INSPECTION OF

ASPHALT ROLL ROOFING ROOFS

Note ; Asphalt roll roofing roofs should not be walked upon

directly. When it is necessary to get on a roof, ladders,

or boards with cleats nailed to them, should be used to distribute the weight.

BUILDING DATE OF INSPECTION

Asphalt Roll Roofing

General Apuearance s Good ___ Fair Poor

Water Tightness ; No leaks Leaks with long-continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of roofing

Faulty material Faulty application: Insufficient

lap Lap not cemented Exposed nails loose

Inadequate nailing Wind damage Hail damage

Traffic on roof Other mechanical damage (describe)

Failure of flashings Other causes (describe)

Condition of Roofing s Apparently unchanged Buckled

Blistered Loss of Granules: Slight Medium

Severe (bare areas)

Asphalt coating damaged (hail, etc.) Coating alligatored

or cracked Other defects (describe)
- 1^+3 -

General Condition of Roll Roofing Roof ;

Treatment Recommended;

Flashings: (Describe condition if defective »)

Chimney flashings:

M .

Satisfactory Defective

Wall Satisfactory Defective

Ridge M . Satisfactory Defective

Vent It . Satisfactory Defective

Valley II . Satisfactory , Defective

Edge It * Satisfactory Defective

Drainage System; (Describe condition if defectiveo)

Gutters: Satisfactory Defective

Downspouts: Satisfactory Defective

Treatment Recommended
- 1^4 -

INSPECTION FORM: ANNUAL INSPECTION OF ASBESTOS-CEMENT ROOFS

Note ; Asbestos-cement roofs should not be walked upon

directly. When it is necessary to get on a roof, ladders,

or boards with cleats nailed to them should be used to

distribute the weight,

BUILDING DATE OF INSPECTION

Asbestos-Cement Roofing

General Appearance ; Good ______ Fair _________ Poor

Water Tightness ; No leaks Leaks with long- continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of roofing materials

Faulty material Faulty Design Faulty construction Wind damage Hail damage Other mechanical

damage (describe) ________________________________________________ Faulty underlayment Failure of flashings Insufficient side lap Insufficient end lap Other causes

(describe)

Condition of Roofing ? Apparently unchanged Loose shingles or sheets (^ ) Broken or cracked shingles (^)

Broken or cracked corrugated sheets {%) Apparent cause

of breakage; Nailed too tightly Mechanical damage ______ Other (describe)

Failure of fasteners; Yes {%) No _______
- 1^-5 -

General Condition of Asbestos-Cement Roof:

Treatment Re c ommended

Flashings; (Describe condition if defective „

)

Chimney flashings; Satisfactory Defective

Wall M . Satisfactory Defective

Ridge M . Satisfactory Defective

Vent M . Satisfactory Defective

Valley M . Satisfactory Defective

Edge M Satisfactory Defective

Drainage System ; (Describe condition if defective .)

Gutters; Satisfactory Defective

Downspouts; Satisfactory Defective

Treatment Recommended;
- lV6 - INSPECTION FORM; ANNUAL INSPECTION OF METAL ROOFS

BUILDING DATE OF INSPECTION

Kind of Metal ; General Appearance ; Good Fair Poor

Water Tightness; No leaks Leaks with long -continued

rain Leaks every rain

Reported Cause of Leaks ; Corrosion Faulty design ___

Faulty construction Insufficient lap Defective

fasteners Broken seams Faulty seams ______ Failure of flashings Other causes (describe)

General Condition ; Rust or corrosion; None Slight

Severe Percent of total area evidencing corrosion

Condition of protective coating (if any); Good Fair

Poor . Seams; Broken - Yes No If yes, location

Number

Breaks (not in seams); Yes No Location

Number Size

Holes; Yes No Location

Number Size

Expansion joints; Too few Sufficient number ___________ If too few, indicate where needed
Treatment Recommended

- 1^7 -

Flashings

(Describe condition if defective,

)

Chimney flashings:

M •

Satisfactory Defective

Wall Satisfactory Defective

Ridge M . Satisfactory Defective

Vent II Satisfactory Defective

Valley II . Satisfactory Defective

Edge II . Satisfactory Defective

Drainage System ; (Describe condition if defective).

Gutters: Satisfactory Defective

Downspouts: Satisfactory _____ Defective

Treatment Recommended
- 148 -

INSPECTION FORM; ANNUAL INSPECTION OF SLATE ROOFS

Note ; Slate roofs should not be walked upon directly* When

it is necessary to get on a roof, ladders, or boards with

cleats nailed to them, should be used to distribute the weight.

BUILDING DATE OF INSPECTION

Slate Roofing

General Appearance s Good Fair Poor

Water Tightness ; No leaks Leaks with long -continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of slate Faulty

material Faulty design Faulty construction

Wind damage Hail damage Failure of flashings Other mechanical damage (describe)

Faulty underlayment Other Causes

(describe)

Condition of Slate ; Apparently unchanged Slate disintegrated; Slight Severe Broken or cracked slate

Apparent cause of breakage: Nailed too tightly

Mechanical damage Other (describe)

Failure of fasteners: Yes (%) No

failures (describe)

Other
- 149 -

General Condition of Slate Roof

Treatment Recommended:

Flashings

(Describe condition if defective »

)

Chimney flashings: Satisfactory Defective

Wall M Satisfactory Defective

Ridge It . Satisfactory Defective

Vent II • Satisfactory Defective

Valley It • Satisfactory Defective

Edge II • Satisfactory Defective

Drainage System ; (Describe condition if defectiveo)

Gutters: Satisfactory Defective

Downspouts: Satisfactory Defective

Treatment Recommended
- 150 -

INSPECTION FORM? ANNUAL INSPECTION OF TILE ROOFS

Note : For Promenade Tile on flat decks use Inspection Form

for Built-Up RoofSo

BUILDING DATE OF INSPECTION

Tile Roofing

General Appearance : Good Fair Poor

Water Tightness ; No leaks Leaks with long-continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of tile Faulty

material Faulty design Faulty construction

Wind damage Hail damage Failure of flashings

Other mechanical damage (describe)

Faulty underlayment

Condition of Tile ; Apparently unchanged Broken or cracked

tiles {%) Apparent cause of breakage: Nailed too

tightly Mechanical damage Other (describe)

Failure of Fasteners : Yes {%) No

Other Failures (describe) ; General Condition of Tile Roof :

Treatment Recommended;
- 151 -

Flashings

(Describe condition if defective ,

)

Chimney flashings; Satisfactory Defective

Wall n

• Satisfactory Defective

Ridge rf •• Satisfactory Defective

Vent ft •• Satisfactory Defective

Valley It •• Satisfactory Defective

Edge M «

• Satisfactory Defective

Drainage System ; (Describe condition if defectiveo

)

Gutters; Satisfactory Defective

Downspouts; Satisfactory Defective

Treatment Recommended
- 152 -

INSPECTION FORM; ANNUAL INSPECTION OF

WOOD-SHINGLE ROOFS

BUILDING date OF INSPECTION __________

Wood Shingles

General Appearance s Good ______ Fair _______ Poor

Water Tightness ; No leaks Leaks with long-continued

rain Leaks every rain

Reported Cause of Leaks ; Weathering of shingles__ Cracked

shingles Curled shingles Failure of shingle nails

Failure of flashings Other causes (describe)

Condition of Shingles s Apparently unchanged _____ Cracked (^)

Curled (^ ) _____ Loose {%')

General Condition of Wood-Shingle Roof (describe) ;

Treatment Recommended

s

Flashings ; (Describe condition if defectiveo)

Chimney Flashings; Satisfactory Defective

Wall " ; Satisfactory Defective

Ridge " ; Satisfactory _____ Defective

Vent " ; Satisfactory Defective
- 153 -

Valley Flashings: Satisfactory Defective

Edge " : Satisfactory Defective

Drainage System ? (Describe condition if defective.)

Gutters: Satisfactory Defective

Downspouts: Satisfactory Defective

Treatment Recommended:
1,

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Figure 2 Bitumen flowing between open joints

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Figure 3. Alligatoring due to a heavy application

of asphalt on a smoothTM surfaced built-up

roof.

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Figure 4. Wrinkles, buckles and lack of adhesion of felts.

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Figure 5 . Exposed nails that have worked loose

from seams of roll roofing.

Figure 6. Roll roofing pulling away from nails

nl tnn n.l nse tn ed?e of sheet.

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k Figure 7. Asphalt shingles nailed too high.

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t Figure 8. Wide selvage roll roofing on H practically flat roof.

END OF THICK PORTION

NAIL BETWEEN THESE LINES

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Figure 9, Action of strong winds on asphalt

shingles nailed too high.

Figure 10. Effect of strong wind blowing perpendicularly

to the ridge of a roll roofing roof.

Figure 11, Leaks caused by entrance of water at

defective flashings are sometimes

attributed to failure of roof membrane.

Figure 12. Results of poor workmanship in

applying a built-up roof.

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Figure 13 • Laying felts mechanically and brooming

in after felt is rolled into hot bitumen.

Figure 1^-. Surface coating of hot bitumen should
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Figure 15. Insufficient bitumen to embed

mineral surfacing.

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Figure l6. Bituminous coating exposed.

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Figure 17, Hot bitumen poured on an unprepared surface.

Note the lack of adhesion.

Figure l8, Felts exposed and weathered.

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Figure I 9 . Small blisters or buckles.

If bare, should be treated

as bare areas.

Figure 20. Severely weathered bitumen coating

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Figure 21, Severe alligator ing on thick coating

of asphalt

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Figure 22. Alligatoring and cracking of a cold coating

over alligatored asphalt surface after one

year exposure.

Figure 23. Comparison of cold coating (asphalt

emulsion) with and without the glass

membrane.

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H^Figure 2h, Typical appearance of asbestos felts after

protective coating has weathered off.

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Figure 25. Exposed and partially disintegrated felts.

Figure 26. Large blister on smooth- surf aced roof

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Figure 27. Felts exposed and disintegrated

in numerous areas.

Figure 28. Loss of mineral surfacing granules

due to normal weathering.

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Figure 29. Differential weathering of asphalt shingles

on Southern and Eastern exposures.

Figure 30. Severe loss of mineral granules and

coating asphalt due to weathering.

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Figure 31* Recoated asphalt shingles. Note

damage due to brittleness.

Figure 32. Proper nailing of asphalt shingles
•I
Figure 33. Location of cement under tabs.ra

Figure 35. Hail damage (shingles not broken).

Figure 36 . Buckles and wrinkles in existing roofing must

be cut and edges nailed down to obtain a flat

surface for application of a new roof.

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RIDGES AND HIPS LAPPED, SHINGLES BLEND-NAILED. LAP AWAY FROM PREVAIL- ING WINDS \

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Figure 37. Application of asphalt shingles over

asphalt roll roofing.

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:
REPAIR

TOP COAT

4" FABRIC

BASE COAT

COVER SEAMS AND NAILS WITH BASE COAT OF ASPHALT ROOF COATING. THEN 4"

STRIP OF ASPHALT-SAT- URATED FABRIC AND

TOP COATING. (FIBROUS ADHESIVE COMPOUND, BRUSH- ING CONSIS- TENCY)

SMOOTH-SURFACED

ROLL ROOFING

REPAIRS TO BUCKLES OVER

SEAMS; SLIT BUCKLES FOR

6" ONLY AND REPAIR AS

DESCRIBED IN TEXT

REPAIRS TO SMALL DAMAGED AREAS: OPEN LOWER SEAM

AND INSERT STRIP AS SHOWN

REPAIRS TO LARGE DAMAGED AREAS; REMOVE DAMAGED SEC- TION AND REPLACE, USING FULL-WIDTH

SHEET LAPPED, CEMENTED, AND NAILED AS

DESCRIBED IN TEXT

VARIABLE EXTEND TO

LOWER SEAM

COVERED EDGE

OF EXISTING ROOF

Figure 38 . Repairing asphalt roll roofing.

Figure 39, Seams of roll roofing repaired with asphalt

satura.ted fabric and asphalt roof coating

(Method I),

Figure ^0. Close-up of Figure 39.
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Figure h2. Puncture resulting from lack

of a cant strip.

Figure 43. Separation of metal flashing _ flange from roof

caused by exposed nails working loose.

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Figure Standing water around vent.

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0 Figure 45. Debris left on roof results in poor drainage.

Figure 46. Drains must be kept clean to function properly.

Figure 47. Standing water resulting from structural defect

Figure ^8. Before. Deterioration of roofing material

where metal gravel stop was omitted.

Figure ^9. After, Section of roof shown in Figure 4-8 after

repair and installation of metal gravel stop.
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Figure 50 Pitch pocket
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I
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major portion of the Bureau’s work is performed

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Commission. The scope of activities is suggested by the listing of divisions and sections on the

inside of the front cover.

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or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications; The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 460, Publications of

the National Bureau of Standards ($1.25) and its Supplement ($0.75), available from the Superintendent of Documents, Government Printing Office. Inquiries regarding the Bureau’s reports and

publications should be addressed to the Office of Scientific Publications, National Bureau of

Standards, Washington 25, D. C.
NBS