Bureau of Standards

DEC S O 1938" :

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• •

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The program of research on building materials and structures undertaken by the

National Bureau of Standards is planned with the assistance of the following advisory

committee designated by the Subcommittee on Design and Construction of the Central

Housing Committee.

TECHNICAL RESEARCH GROUP

Walter Junge, Federal Housing Administration, Acting Chairman

A. G. Beak,

Veterans' Administration.

Pierre Blouke,

Home Owners' Loan Corporation.

C. W. Chamberlain,

Procurement Division. Jos. M. DallaValle,

Public Health Service.

Hugh L. Dryden,

National Bureau of Standards.

G. E. Knox,

Bureau of Yards and Docks, Navy

Department.

Charles E. Matette,

United States Housing Authority.

Vincent B. Phelan,

National Bureau of Standards.

E. A. Poynton,

Bureau of Indian Affairs.

John H. Schaefer,

Procurement Division.

A. C. Shire,

United States Housing Authority.

George W. Trayer,

United States Forest Service.

Elsmere J. Walters,

Quartermaster Corps, War Department.

Sterling R. March,

Secretary.

The program is administered and coordinated by the following staff committee of the Bureau:

Hugh L. Dryden, Chairman

P. H, Bates

H. C. Dickinson

W. E. Emley

G. E. F. Lundell

A. S. McAllister

H. S. Rawdon

The Forest Products Laboratory of the United States Department of Agriculture

is cooperating with the National Bureau of Standards in studies of wood constructions.

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UNITED STATES DEPARTMENT OF COMMERCE • Daniel C. Roper, Secretary

NATION A I, BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS6

Survey of Roofing Materials

in the

Southeastern States

by HUBERT R. SNOKE a/ld LEO J. WALDRON

ISSUED NOVEMBER 4, 1938

The National Bureau of Standards is a tact-finding organization;

it does not "approve" any particular material or method of construction. The technical findings in this series of reports are to be construed accordingly.

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • 1 93 8

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE 15 CENTS
Foreword

The present paper describes tlie results of a survey of the weathering quahties and

extent of use of the various roofing materials on dwellings in nine Southeastern States.

Tliis survey, which was made with the cooperation of representatives of the Reconditioning Section, Home Owners' Loan Corporation, involved approximately 3,500 miles of travel by automobile.

The results of detailed studies of roofing materials on new and old constructions in

representative cities are included, as well as a tabulation, by States, of the kinds of

roofing materials used on more than 10,000 rural and small town dwellings along approximately 2,500 miles of highway. More than 400 photographs, showing types of weathering of roofing materials, and features of design and construction of roofs, were taken in

the course of this survey. From these, 48 have been selected for publication.

It should be emphasized that the observations that are recorded in the present

report apply only to the territory covered by this survey. It is planned to supplement

this work with similar surveys in other sections of the country.

Lyman J. Briggs, Director.
Survey of Roofing Materials in the Southeastern States

by HUBERT R. SNOKE iiud LEO J. WALDRON

CONTENTS

Page Foreword ii

I. Introduction 2

II. Method of iiiakiug the survey 2

1. Extent of use of roofing materials in rural sections 2

2. Study of the weathering qualities and extent of use of roof- ing materials in the urban

centers 2

III. Extent of use of the various roofing materials in rural districts and

small towns in the Southeastern

States 3

1. Factors which affect the choice

of roofing materials in rural

sections 3

2. Factors which affect the choice

of roofing materials in small towns 3

3. Territory covered and routes followed in making survey.- 3

4. Extent of use of particular materials in rural sections and

small towns 4

5. Summary of the extent of use of the various roofing materials

in rural sections and small towns in the Southeastern

States 4 IV. Weathering qualities of roofing materials in the Southeastern

States 4

1. General discussion 4

2. Discussion of particular materials 5

(a) Asphalt shingles and roll roofings 5

(b) Wood shingles 8

(c) Cement-asbestos shingles 8

(d) Slate 8

(e) Tile roofing 17

(f) Metal 17

3. Flashings, valleys, gutters, and

downspouts 18

(a) Flashings 18

(b) Valleys 18

(c) Gutters and downspouts. 18

Page V. Extent of use of the various roofing materials in urban centers of the Southeastern States.. 19

1. Factors which affect the choice

of roofing materials generally. 19

2. Factors which affect the choice

of particular materials 19

3. Distribution of roofing materials in the cities covered by this survey 20

(a) Greensboro, N. C 20

1. New construction. _ 20

2. Old construction .. 20

(b) Columbia, S. C 20

1. New construction. . 20

2. Old construction 20

(c) Savannah, Ga 20

1 . New construction . . 20

2. Old construction 20

(d) Jacksonville, Fla 21

1. New construction _ _ 21

2. Old construction 21

(e) Orlando, Fla 21

1. New construction. _ 21

2. Old construction __ 21

(f) Birmingham, Ala 21

1. New construction. „ 21

2. Old construction 21

(g) Atlanta, Ga 21

1. New construction. _ 21

2. Old construction 22

(h) Knoxville, Tenn 22

1. New construction. . 22

2. Old construction 22

(i) Charleston, W. Va 22

1. New construction. _ 22

4. Summary of extent of use of the various roofing materials in urban centers in the Southeastern States. .. 22

(a) New construction 22

(b) Old construction 22

5. Costs of roofing materials, in- cluding cost of application,

in urban centers in the Southeastern States 23

[1]
ABSTRACT

A survey of the weathering qualities and extent of use

of the various roofing materials on dwellings in the Southeastern States is described. Detailed studies of roofing materials in Greensboro, N. C, Columbia, S. C,

Savannah and Atlanta, Ga., Jacksonville and Orlando,

Fla., Birmingham, Ala., Knoxville, Tenn., and Charleston, W. Va., are reported. A tabulation, by States, of the kinds of roofing materials used on more than 10,000

rural and small town dwellings, along approximately

2,500 miles of highway, is included. Forty-eight

photographs, illustrating types of weathering of roofing materials and features of design and construction of

roofs, are shown.

I. INTRODUCTION

The general research program of the

National Bureau of Standards on building

materials and structures includes, as part of

the work on roofs and roofing materials, a comprehensive survey of the various types of

roofing materials used, with observations on

their weathering qualities, on roofs of known

history, in locations typical of widely differing

climatic conditions in the country. It was

decided that surveys of this kind would give

information of more direct value than would

accelerated-weathering tests in the laboratory.

This paper describes a survey of the weathering qualities of roofing materials commonly

used in the following cities: Greensboro, N. C;

Columbia, S. C; Atlanta and Savannah, Ga.;

Jacksonville and Orlando, Fla.; Birmingham,

Ala. ; Ivnoxville, Tenn. ; and Charleston, W. Va.

with estimates on the extent of use of the

various materials in these cities. There is also included a report on the extent of use of

the different roofing materials on rural dwellings

along the highways between the cities that were visited. A distance of approximately

3,500 miles was traveled in this survey, from

April 4 to 27, 1938.

It cannot he emphasized too sti^ongly that the observations on the weathering characteristics of

roofing materials that are recorded in this paper

apply only to the territory covered by this survey. Obviously, these observations should be the same

where conditions of exposure elsewhere are

identical, but it is equally obvious that they

would not be the same for different conditions of exposure.

II. METHOD OF MAKING THE

SURVEY

1. Extent of Use of Roofing Materials

IN Rural Sections

All travel in connection with this survey was by automobile. In order to determine the extent of use of the different roofing materials on dwellings in the rural sections and small ) towns, an actual count was made of all roofs

along the highways traveled. The record was

kept on special forms, each covering 50 miles

of highway, forms also being changed at State

lines to permit tabulation by States. No attempt was made to record the condition of roofs in the rural sections, although some obvious facts concerning the weatheringcharacteristics of the various materials were

noted.

2. Study of the Weathering Qualities and

Extent of Use of Roofing Materials in

Urban Centers

One of the chief difficulties in making a ! survey of this kind is that of obtaining roofs

| of known history for examination. This dif- , ficulty was eliminated to a considerable extent

^ in this survey by the cooperation of represent- i atives of the Home Owners' Loan Corporation,

both in Wasliington, and in the regional, State, , and district offices in the various cities. The exact procedure was as follows: The . chief of the Reconditioning Section, Home

Owners' Loan Corporation, in Washington, i through his regional reconditioning supervisors,

notified the State reconditioning supervisors of

the dates of arrival of representatives of the

Bureau, and requested that they have available on those dates: (a) Some person who was

thoroughly familiar with the city, and with

local conditions of construction; (b) a list of roofs of dift'erent kinds and of known history;

(c) a list of prices and costs of application of roofing materials used locally; (d) locations of

low-cost housing projects; (e) names of several

reputable roofing contractors; and (f) a ladder

and means of transporting it. Acknowledgment is here made to the repre- sentatives of the Home Owners' Loan Corporation, both in Washmgton and in the field, for their wholehearted cooperation in this work.

[2]
In each city, a short tmie was spent in dis- cussing the details of the investigation with

representatives of the Home Owners' Loan

Corporation and then, witli them, in discussing

roofing practices with local roofing contractors. Actual inspections were then made of as many

roofs as time would permit, followed by a

general tour of the city, including long-established and new subdivisions to determine

roughly the extent of use of the various roofing

materials. WliUe prelimmary lists of roofs

had been prepared in most locations, it was also a regular practice to request permission to examine any roofs that looked particularly

interesting. In no case was permission refused.

III. EXTENT OF USE OF THE VARIOUS

ROOFING MATERIALS IN RURAL DISTRICTS AND SMALL TOWNS IN THE

SOUTHEASTERN STATES

L Factors Which Affect the Choice of

Roofing Materials in Rural Sections

Initial cost is undoubtedly the greatest

single factor in the selection of roofing materials

for rural dwellings in the Southeastern States. Wliile the area covered included some of the

most productive farming sections in the country,

by far the greatest number of roofs tabulated were on dwellings in the very lowest price

classes. Direct evidence that cost is the most

important consideration is furnished by the

fact that the use of the more expensive materials, such as slate and tUe, is practically

negligible in the rural districts. Availability of

particular materials is another important factor. Wood shingles and shakes have had wide use

in the past in sections where cypress, pine, and

chestnut have been produced. It is worthy

of note, however, that but very few (not over

10) new wood-shingle roofs were observed in

the whole area. Appearance is apparently of little influence

in the majority of cases, but it was definitely

evident that the more attractive roofings were

used on dwellings whose general appearance was better than the average. Rural dwellings

are not subject to fire regulations, other than

those imposed by increased insurance rates

for nonfireproof materials. No doubt the fire

resistance of metal roofs lias been of considerable

influence in their wide use.

2. Factors Which Affect the Choice of

Roofing Materials in Small Towns

The factors which influence the use of particular materials in small towns are essentially the same as those in large cities, though probably

not in the same degree. Cost is the most important consideration, for the more expensive

materials are foimd on dwellings in the higher

price classes. Appearance is undoubtedly a

greater influence than in the rural areas. Mamtenance cost in a very strong factor in small towns such as are found in the mining

sections of Kentucky and West Virginia, where

practically all dwellings in many villages are owned by coal companies.

3. Territory Covered and Routes Followed

IN Making Survey

A map of the territory covered and a list of the cities and routes in the order they were

traveled, are given below.

States covered hy survey.

[3]
Cities Routes '

Washington, D. C., to Greensboro, 1 and 70. N. C. Greensboro, N. C. to Columbia, S. C _ 220, 1, 1.5, and

76. Columbia, S. C. to Savannah, Ga (3) and (33). bavannah, Ga. to Jacksonville, I<la_ _ 17. Jacksonville, Fla. to Orlando, Fla 1 and 92. Orlando, rla. to Birmingham, Ala 441, 19, 27, 84, and 31.

T» • * 1 A 1 J. A XI X /"I Birmingham, Ala. to Atlanta, Ga 78. Atlanta, Ga. to Knoxville, lenn 41, (71), and 11. Knoxville, lenn. to Charleston, (33) and 119. W. Va.

1 X TT7 "XT X TT7 1_ " X Charleston, W. Va. to Washington, 60, 11, and 211. D. C.

' state routes in parentheses, all others are U. S. routes.

4. Extent of Use of Particular Materials

IN Rural Sections and Small Towns

Table 2 is a tabulation, by States, of the

kinds of roofing materials used on dwellings in rural sections and small towns along the routes

listed in section III (3). Table 2. —Tabulation, by States, of the kind of roofing materials used

br. C

;ossh

State ingl To

best g ,g C H

OJ S

«0

Miles

Asphal Wood

s

Slate

Cemen CD

Metal: Roll

ro

Tile

Total

Vireinia (W)_ .. 250 140 43 14 4 797 40 68 1 Vireinia (E) 200 328

468

24 33 7 363 26

66 unVirginia (total) . . 450 67 47 11 1, 160 178 1 1,998 North Carolina. . - 221 678 269 7 9 357 84 29 1 1,434 South Carolina 263 102 294 2 3 330 22 18 771 Georgia (SE) 140 36 76 21 191 8 17

8 "iGeorgia (SW) 50 13 47 2 67 6 Georgia (N) 150 517 258 "2

4 291 41 131 Georgia (total) 340 566 381 2 27 649 64 156 1 1,736 Florida 421 105 128 1 46 204 47 99 28 658 Alabama 300 229 460 4 50 466 36 92 2 1, 339 Tennessee 133 218 85 30 272 63 16 10 684 Kentucky ... , 178 87 51 7 238 2 610 995 West Virginia.- . . 141 105 22 "i 1 146 2 784

" i 1,062

Total 2, 447 2, 558 1,757 64 184 3, 722 366 1,982 44 10, 677

Summary of rural count

Miles covered _ 2,447 Sheet metal roots 3,722 Asphalt shingle roofs 2,558 Roll roofing roofs 1,982 Wood shingle roofs 1, 757 Metal shingle roofs 366 Cement-asbesfOS roofs 184 Slate roofs 64 Tile roofs 44

Total- - 10.677

This count was not limited to dwellings

actually on the highways, but included all that were visible in passing. In small villages of 20 or 30 dwellings, usually all would be included,

and in some larger villages, notably mining

towns in West Virginia and Kentucky, where

practically all dwellings were roofed with the same materials, as many as 200 roofs might

be listed in a single town. Larger towns and

cities were not included, the count being stopped

in the suburbs of the larger centers.

5. Summary of the Extent or Use of the

Various Roofing Materials in Rural

Sections and Small Towns in the

Southeastern States

The foregoing summary is essentially a count

of the roofs used on rural dwellings, except in

Kentucky and West Virginia, where 610 and

784 roll roofings are tabulated, respectively.

Roll roofings were practically negligible in the

strictly rural sections of these States, most of

these roofings having been tabulated in mining

villages. The addition of these villages indi- cates many more roofs per mile than are actually

found on the routes traveled in these States. Only the most general observations were

possible on the weathering qualities of roofing \ materials in rural sections and small towns.

Certain facts that were obvious are: (a) Practically no new wood-shingle roofs are being

constructed; (b) V-crimp and corrugated galvanized metal roofs are most widely used in

the rural sections. The vast majority of these

roofs on the cheaper dwellings are unpainted;

and (c) the increasing popularity of aluminum

paints for metal roofs on more expensive rural

dwellings was evident in the Shenandoah

Valley of Virginia, where the standing-seam

metal roofs on many fine old homes have been

coated recently with paints of this type.

IV. WEATHERING QUALITIES OF

ROOFING MATERIALS IN THE SOUTHEASTERN STATES

1. General Discussion

Any discussion of the weathering qualities

of roofing materials in a particular section of the country must, of necessity, be couched in

[4
the most general terms. Many factors other

than the actual materials used must be considered in studies of the durability of roofs. No two conditions of exposure are ever identical.

Thus, two dwellings may be built side by side, of the same materials and design; one may re- main dry tliroughout the building operations,

whereas the wood sheatliing on the other may

be thoroughly soaked by several days of rain; one may be shaded by trees which protect it from the effect of sunlight, but subject it to damage from falling branches, whereas the

other may receive the full effect of sunlight.

These roofs, in all probability, will show differ- ent weathering characteristics. The same

materials on roofs of different pitch will behave

differently, a fact that can be observed fre- quently where the same material is used for the

steeply pitched main roof sections and the lowerpitched porch roofs. The northern exposure of a roof is invariably less severe than the southern

exposure. Faulty workmanship probably causes more

premature roof failures than faulty materials.

A roof well laid with inferior materials wiU give

good service as long as the material wiU withstand the effects of weathering, but a roof

improperly laid with good materials will probably give poor service from the beginning.

Wlien the materials used for roofing are considered, the problem becomes even more complicated. Asphalt sliingles can be obtained in a wide variety of shapes and colors, and in weights

ranging from 125 to 325 pounds per square

when laid on a roof; slate for roofijig purposes is produced in several localities in a variety of

sizes, weights, and colors; metal shingles may

be of terneplate, commonly known as "roofing

tin";- galvanized steel, copper, or zinc, in numerous shapes and designs; and sheet-metal

roofs may be of "roofing tin," galvanized steel, copper, etc., of different weights of coatings

and gages of metal, and laid on the roof by a niunber of different methods. This multiplicity applies equally to other kinds of roofing

materials.

Another factor wliich precludes definite and

1 No distinction is made in this discussion between steel or wrought-iron

sheets coated with tin only, "bright tin sheets," which were sold formerly

as "roofing tin," and present-day "roofing temes" or "terneplate" made

by coating steel sheets with an alloy containing about 80 percent of lead and 20 percent of tin.

positive statements concerning the "life" of

any particular roofing material is the difficulty

of determining just when a roof has failed and

exactly what constitutes a failure in a roofing

material. Theoretically, a roof that does not

adirdt water might be considered serviceable,

yet roofs may be serviceable and still not be

satisfactory. Appearance is a factor that is becoming increasingly important in choosing

roofuig materials, but it is a variable factor

that cannot be weighted generally.

It can be readily understood, therefore, that no positive statement can be made concerning

the probable service that a given, general type

of roofing material will render in a particular

locaHty. However, some of the materials, as

classes, do show different weathering characteristics in different locations. An attempt has

been made to discuss, and illustrate by means of photographs, certain of the weathering characteristics of the roofing materials used in the

Southeastern States. No attempt is made in

this discussion to differentiate between manufacturei's of roofing materials.

2. Discussion of Particular Materials

(a) Asphalt Shingles and Roll Roofitigs

Asphalt shingles have been developed chiefly

within the past 30 years, yet today they are used more generally on dwellings in urban

centers throughout the Southeastern States

than any other roofing material. Because of

this wide use, these materials wiU be considered

ia greater detail than other roofings.

In a previous paper on accelerated-weathering

tests of asphalt sliingles,^ types of weathering were discussed under the foliowdng headings:

Color changes, blistering, pitting, loss of granules, cracking, warping, behavior of back coating, slippage, and water absorption. No defi- nite report coidd be made on color changes of

roofing granides in this survey, because original

shingles were not available for comparison.

The covered portion of a shingle is usually

stained by the back coating of the shingle wliich covers it, so that it cannot be taken as a true standard for color. However, considerable fad2 Hubert R. Snoke and Braxton E. Gallup, J. Research NBS 18, 669

(1937) RP1002.

[5]
ing was noted, particularly in certain natural

green and blue-black granules.

No slippage of the top asphalt coating was

noted in any locality, but considerable blistering

of back coatings was seen. Figure 1 illustrates

this type of behavior. In some cases the butts

of shingles laid recently had become cemented

to those underneath so tightly that they could

not be lifted. Blisters in the top coating of asphalt sliingles were found quite frequently. These varied

from scarcely detectable small blisters to the

large tent-like ones which covered a considerable area. They were not confined to particular types of shingles or granules, or to any

particular location. However, they were noted on shingles surfaced with buff granules, or blends of other granules with bufl^, more fre- quently than on others. Also more sliingles

with blisters were observed in Orlando, Fla.,

than in any other location. Figure 2 shows

typical blisters on an asphalt-shingle roof near

Charleston, W. Va. This roof was surfaced

with a blend of granules of dift'erent colors and

had been exposed about years. Some slight

buckling can be noticed in several of these

shingles, apparently caused by the use of

unseasoned lumber for sheathing.

Pitting, which is a further development of

blistering, was observed in all degrees. Figure

3 shows pits from small blisters and figure 4

the type formed by large blisters. Loss of granules accompanies all types of

advanced weathering. Figure 5 illustrates

shingles that have weathered badly, but which

are just beginning to show a decided loss of

granules. Figure 6 shows shingles that have

lost not only granules but practically all of the

coating asphalt. This illustration was typical

of numerous old asphalt-shingle roofs that were

observed, mostly of individual sliingles laid by

the American method. Note that most of the

shingles show no curling or buckling. This

roof, in Savannah, Ga., was 15 years old, and,

as reported by the owner of the dwelling, did

not leak. Loss of granules caused by mechanical

damage is illustrated in figure 7. Note the

badly weathered condition of the shingles on

the porch roof as compared with those on the

roof of the house. Water falling from the main

roof section to the porch roof has been the

principal cause of the more advanced weathering of the latter, though the difi^erence in the

j pitch of the two roofs may have been partly '

responsible.

Loss of granules, accompanied by curling, in

j a segregated section of a roof is illustrated in ' figure 8. Apparently this type of failure is caused by a defect in the sheet from wliicli the

^ shmgles are cut as it comes from the machine. [ These sliingles may have been cut from the i sheet longitudinally, with the butts taken from I the edge of the sheet. The sliingles from the

^ defective section are placed in the same bundle j and consequently are segregated on the roof.

\ Another common type of weathering, including

| loss of granules and curling, is illustrated in j figure 9, where one tab of each sliingle has lost i graniUes and curled. In each case the tab that '

is affected is at the end of a shingle, that section s probably being taken from the edge of the sheet.

^ Cracking of shingles was observed only in ( those that were weathered so badly that all the ] coating and granules were gone and the felt

jj was disintegrated. Typical alligatoring of the j, asphalt coating, wliich develops into cracks, is ' shown in figure 10, representing shingles ap- * proximately 15 years old in Columbia, S. C. ; The section of the roof where this photograph , was taken was protected from the sunlight. ! Illustrations of warping or curling have been

noted imder loss of granules above. Warping

due to no fault of the shingles is shown in fig- ure 1 1

, where apparently the use of wet or un- seasoned lumber under the shingles was responsible. Asphalt shingles are frequently laid over ^ weathered wood or asphalt shingles when used j for reroofing. When laid over wood sliingles, j any curled shingles should be removed or nailed ^ down, and beveled wood strips inserted at the j butts to insure a smooth surface and permit j proper nailing of the asphalt shingles. Indi- i( vidual shingles laid by the Dutch lap or hexagonal methods, which give but single coverage |( over a large pz'oportion of the roof area, are .j used frequently for reroofing. Difficulties that

may be encountered with single-coverage shin- < gles laid directly over wood shingles are illus- j trated in figures 12 to 16, inclusive. Figure 12 t shows the curled corner of a wood sliingle that

[6]
has worn a hole tlirough the single thickness of asphalt sliingle over it. Figure 13 shows a nail

that had been used to fasten down the corner of a wood shingle but which has worked loose and

been forced through the asphalt shingle. Both

of these were taken on a roof 6 years old, in

Columbia, S. C. Figure 14 shows a section of

the same roof damaged by winds. Figures 15

and 16 show sections of an asphalt shingle roof

10 years old, in Orlando, Fla. These were

heavy-weight slihigles, 10 by 14 inches in size, laid directly over weathered wood shingles to give but single coverage over a section about 5 by 6 inches in size. The wood shingles under

these asphalt sliingles had almost completely

disintegrated. Apparently in this case water

had been driven imder the asphalt shingles and

wetted the wood shingles, wliich remained wet

for a comparatively long time. Moisture from

the wood sliingles entered the asphalt shingles

through the thin layer of asphalt coating on the

back and under the hot smi, caused blisters. The bHsters, composed of a thin layer of asphalt, soon broke open and exposed the felt to the

weather.

No attempt will be made to estimate the

probable life of asphalt shingles m the various

cities visited. In each city*, however, the oldest

roofs found were of individual shingles, laid by

the American method. These shingles were the

first produced, so that naturally they should be

the oldest. Yet it is believed that individual

asphalt shingles, laid by the American method,

provide the most satisfactory asphalt sliingle roofs today because, when laid properly, they

afford triple coverage over practically the whole

area of the roof. Roofs laid with sliingles of

this type are illustrated in figures 5, 6, 10, 17,

and 18. Figures 5 and 17 represent the northern and southern exposures, respectively, of a

roof 13 years old, in Savannah, Ga., laid with

heavy-weight asphalt shingles. Figure 6 is a

15-year roof of the same type in the same city.

Figures 10 and 18 represent shaded and unshaded sections of a roof laid by the same method in Columbia, S. C. Numerous roofs

so constructed were found in Birmingham, Ala., some of wluch were in fairly good condition

after 15 years, and one after about 17 years

had weathered approximately the same as the

13-year roof in Savaimah. In Charleston, W.

Va., the oldest roofs of this type were found on

dwellings erected by the Federal Govci-nmeiit

in 1918. Most of these dwellings had been re- roofed recently, but several that had not been were reportetl as not leaking. Practically all of

the surfacing granules and asphalt coating had

disappeared from these roofs. The above illustrations were chosen to show

specific types of weathering aiul to give some

idea of the service that may be expected from

asphalt shingles. It is not intended to convey

the impression that all asphalt shingles will show

severe weathering in a relatively short period.

Figure 19 shows an asphalt slungle roof in Jacksonville, Fla., that was 12 years old and was

still in very good condition. Figure 20 is a

10-year roof in Greensboro, N. C, that was in

good condition. Both of these were of strip

shingles.

It was noted that asphalt shingles weather more rapidly the farther south they are exposed.

From many observations, it is obvious also that the greater the weight of asphalt shingles

per unit area of roof, the better the service.

Mineral-surfaced asphalt-prepared roll roofing

exhibits essentially the same types of weathering as asphalt shingles, although the roll roofing

apparently is more susceptible to blistering

than the asphalt shingles. Figure 22 shows

large blisters, almost natural size, with one broken blister. Figure 23 shows a crack in

mineral-surfaced roofing. Both of these were

taken on a roof about 4 years old m Jacksonville, Fla.

In general, asphalt shingles give longer service

than the mineral-surfaced roll roofing because

the latter affords but single coverage. RoU

roofing is difficult to apply without wrinkles, but

when laid properly may outlast some improperly laid shingles, particularly those of lighter

weight.

Smooth-surfaced roll roofing weathers more

rapidly than the mineral-surfaced roofing be- cause the asphalt coating is exposed directly to the action of sunlight and moisture. Faulty

application causes failure in many of these roofs. Figure 25 illustrates smooth-siu'faced asphaltprepared roll roofing, well applied, that shows

very little weathering after 5 years' exposure in

Orlando, Fla. Figure 43 illustrates a 4-year

roof, improperly applied, in the same city.

88924°—.S8 2 [7]
(b) M^ood Shingles

Work on wood shingies in this investigation was limited to such observations as were neces- sary for a comparison of them with other roofing

materials. Practically no opportimity was

given to examine wood sliingies, since all the

cities visited either proliibit or strictly limit

their use. Some very old wood sliingle roofs were observed in each locality. Cypress shingies produced locally in some sections were

reported to ha ve given particularly good service.

(c) Cement-Asbestos Shingles

The oldest cement-asbestos roof of known

history that was inspected was on the ocean

front at Daytona Beach, Fla., and hence was

subject to very severe conditions of exposure.

This roof was 27 years old, and, except for a few broken shingles, appeared to be in good

condition. See figure 28. The owner reported

that most of the breakage had been caused by

walking upon the roof, but that a few shingies

had been broken recently at the naU holes by'

corrosion of the shanks of the galvanized nails

that were used to fasten them. Close examination of these shingies shows a considerable degree of weathering on the siu-face. That is, the

surface was roughened somewhat and the as- bestos fibers were plainly visible (fig. 29), but

weathering had not progressed to the extent

that the exposed portion of a shingle appeared

thinner than the unexposed portion. These

shingles were 16 by 16 inches m size and were

laid by the American method with a 7-inch

exposure.

The type of weathering described above is typical of old cement-asbestos slungles examined

in each of the locations visited. Since these

materials have had but a limited use, except in Savamiah, Ga., comparatively few cement-asbestos roofs were examined critically. Most of

the older roofs were laid by the French or hexagonal method, while many of the newer roofs are being laid by the Dutch lap method.

In general, these shingles have given excellent

service. Like other rigid roofing materials they

are subject to damage when lunbs of trees or other heavy objects fall upon them, or when

they are walked upon directly; also by the

shrinkage of wet or unseasoned lumber in the

roof structure. The most noticeable effects of

weathering are color changes. The color is applied to many of the colored shingies as an ex- tremely thin coating which weathers badly in a comparatively short time. This was particularly noticeable in the green shingles. All types

appear to collect considerable dust and dirt

which give the shingles a dingy appearance after long exposure. Since it is unusual for all sec- tions of a roof to have the same conditions of exposure, some sections may remain comparatively clean, while the original color of other

sections may be entirely hidden.

Differences in the degree of weathering of roofings of tlus type, exposed for approximately

the same periods, could not be determined in the

short time spent in the various locations. It is doubtful if this would have been possible in a more exhaustive study.

(d) Slate

Slate roofs, usually considered as permanent,

may show decided weathering characteristics.

Obviously it would be impossible to secure complete data on slate roofs 50 or more years old ; yet

certain slates, regardless of age, may be identified. Among these are the colored slates from

the Vermont area. These are used to a very

limited extent in the South, usually on the more

expensive dwellings, because the freight charges

make their cost very high. Apparently they

withstand weathering well. Other slates not difficult to recognize and

probably used more extensively through the

South than any others were unfading slates from

Virginia. Slate has been quarried in Virginia

since 1787 and many very old slate roofs in the

Southern States are from this area. They show

little or no change in color on long exposure

A number of very old slate roofs that had

weathered to a brownish color were found in

Atlanta, Ga. These slates were reported as coming from the Rockmart quarries in Georgia,.

Some fading slates from the Eastern Pennsylvania quarries were also observed, the roof on

the old court house in Orlando, Fla., apparently

being of tliis type. Tliis roof is about 45 years

old and is in good condition except that the

slates show considerable fading. Figure 30

shows a roof of Vermont slate, in good condition

after 30 years of exposure in Orlando, Fla.

[8]
Figures 1 to G.

Asphull sIiiikjI(s.

Figure l, blisters on back coating of shingle exposed 10 years in Orlando, Fla.; 2, blisters on shingles exposed

3>-> years near Charleston, W. Va.; 3, pits from small blisters. Shingles exposed 10 years in Orlando, Fla.;

4, pits from large blisters. Shingles exposed 12 years in Columbia, S. C; 5, slight loss of mineral surfacing

granules. Northern exposure of a roof in Savannah, Oa., 13 years old. See figure 17; 6, almost complete

loss of mineral surfacing granules and asphalt coating on shingles exposed 15 years in Savannah, Ga,

[9]
FiGURjis 7 to 12.

Asphalt shingies.

Figure 7, re-cover shingles exposed 7 years in Greensboro, N. C. Note difference between main roof section and porch roof; 8, loss of mineral surfacing granules, with curling of shingles, in a segregated section of a roof;

9, loss of mineral surfacing granules, with curling of shingles, after 12 years of exposure in Orlando, Fla.;

10, alligatoring of asphalt coating. Shaded section of a roof exposed 15 years in Columbia, S. C. See figure

18; 11, warping of shingles exposed 3!.2 years near Charleston, Va. Probably caused by wet or unseasoned lumber; 12, close-up of damage to an asphalt shingle laid over a wood shingle. Photograph taken

after about 6 years of exposure.

[10]
Figures 13 to 18.~Asphalt shingles.

Figure 13, close-up of damage to an asphalt shingle from a wood shingle nail. Same roof as in figure 12;

14, asphalt shingle roof damaged by wind. Same roof as in figures 12 and 13; 15, badly weathered asphalt

shingles laid directly over wood shingles, after 10 years of exposure in Orlando, Fla.; 16, ciose-up of a section

of the roof shown in figure 15; 17, severe weathering of shingles. Southern exposure of a section of the roof shown in figure 5; 18, severe weathering accompanied by loss of granules and asphalt coating. Unshaded

section of the roof shown in figure 10.

[11]
Figures 19 to 24.

Asphalt shingles and roll roofings.

Figure 19, asphalt shingles in good condition after 12 years of exposure in Jacksonville, Fla.; 20, asphalt

shingles in good condition after 10 years of exposure in Greensboro, N. C; 21, valley formed by interlacing butts of asphalt shingles; 22, blisters in mineral-surfaced asphalt-prepared roll roofing exposed 4 years in Jacksonville, Fla.; 23, crack in mineral-surfaced asphalt- prepared roll roofing. Same roof as in figure 22;

24, mineral-surfaced asphalt-prepared roll roofing made to simulate asphalt shingles.

[12]
Figures 25 to 30.

Asphalt- prepared roll roofing, cement-asbesios shingles, and slaie.

Figure 25, smooth-surfaced asphalt-prppared roll roofing, exposed 5 years in Orlando, Fla.; 26, smootli- sarfaced asphalt-prepared roll roofing, vertical application. Atlanta, Ga.; 27, smooth-surfaced asphalt- prepared roli roofing, vertical and horizontal application. Atlanta, Ga.; 28, cement-asbestos shingle roof, exposed 27 years in Daytona Beach, Fla.; 29, close-up of cement-ashestos shingles from roof shown in figure

28; 30, slate roof exposed 30 years in Orlando, Fla.

[13]
[14]
Figures 37 to 42.

Sheet metal and metal shingles.

?igure 37, metal shingles on root for 25 years in Savannah, Ga.; 38, metal shingles on roof for 3 years in Savannah, Ga.; 39, V-crimp metal roof in Birmingham, Ala.; 40, corrugated-metal roof in Orlando, Fla.; 41, stand- ing-seam metal roof in Savannah, Ga.; 42, metal shingles on root in Columbia, S, C,

[15]

111
Figures 43 to 48.

Chimney flashings.

Figure -13, roll roofing turned up as flashing; U, asphalt shingle used as flashing; 45, metal flashing; 46, saturated-felt flashing; 47, plastic flashing; 48, metal flashing.

a

[161 .
Figures 31 and 32 show almost complete deteiioration of ribbon slates ^ after about 10 yeai's of

oxposui'e in West Virginia.

Slate is another ligid roofing material that is subject to breakage by heavy objects falling

upon it or by being walked upon directly. It may also be damaged if it is laid on wet or unseasoned lumber, particularly if the nails are driven too tightly. When laid properly, and of a f)roper grade, slate has given very satisfactory

service. Differences in the degree of weathering

of the various slates in the different locations

could not be distinguished.

(e) Tile Roofing

Ceramic (clay) tile roofs, used only slightly in

the locations visited, appeared to have given

excellent service. Damage to them from actual

weathering is very slight, but they are also subject to breakage by heavy objects falling upon

them or by being walked upon directly. No

differentiation in the degree of weathering of

these materials could be determined in the

various cities. Figure 33 shows a heavy mission tile roof 15 years old in Jacksonville, Fla.

Cement tile roofs, manufactured in a number of southern cities, are used to a greater extent than the ceramic tiles. They are extremely

heavy and, because their surfaces are somewhat

rough and porous, they have a tendency to

collect dust and dirt. Figure 34 shows a roof

of this type, 15 years old, in Columbia, S. C.

(/) Metal

The climatic conditions in the Southeastern

States are very favorable toward the durability

of metallic roofings, particularly galvanized

materials, which probably explains the reason such materials give satisfactory results. More

corrosive conditions prevail along the seacoast,

which tend to decrease the life of unpainted

metallic materials whereby the item of adequate

3 "Bands of different color, texture, and composition in slate are com

monly called ribbons. The most common ribbons are darker in color than the main part of the slate and vary in width from a fraction of an

inch up to several inches." D. W. Kessler and W. H. Sligh, BS J. Research 9, 381 (1932) EP477. "When exposed to the vreather the ribbons in the 'soft-vein' slate of Pennsylvania decompose more readily than the clear stock. In si<le walks, made of ribboned slate, deep grooves have commonly resulted from

the weathering of the ribbons. The ribbons in the 'hard-vein' slate of Pennsylvania resist weathering." Oliver Bowles, Bulletin 218, V. S. Bureau of Mines, p. 11 (1922).

maintenance becomes ati important factor in governing the life of the material. Little

evidence was found where expansion and contraction were important considerations in

causing prematui-e failures of metal roofs. Apparently tliis factor has been taken cme of

properly in the design of the roofing material

and its subsequent installation.

Only a small amount of sheet copper of the

conventional weight used normally for roofing was found in this survey, and its use was

restricted to monumental buildings, cliurches,

post offices, etc. A type of new roofing material

that is being used in Florida, and also in some

other sections of the country, is made from

copper sheet, weighing approximately 3 ounces

per square foot. It is applied in long lengths,

parallel with the eaves, in widths of 1 to IK

feet. It is given a shingle appearance either

by crimping or by the insertion of lath at regular

intervals. Sheets of electrolytically deposited

copper were originally applied as roof coverings

in Florida some 4 or 5 years ago and a few of these roofs were inspected at Orlando, Fla.

Apparently they have given satisfactory service

to date, though this particular variety of sheet

is not used at the present time (fig. 35). RoUed

copper sheet, backed with either paper or asphalt-saturated felt, has been used for 2 years and makes an attractive roof, as shown in

figure 36. The short time it has been used pre- cludes any prediction as to its behavior over a long period.

Metal shingles are used to a limited extent in

most sections of the South. The older type of

embossed or stamped design can be foxmd in

most communities. Satisfactory service for periods of 20 to 30 years has been rendered by

these shingles when they are painted periodically, with numerous cases where the life has

extended up to 50 years. Figure 37 shows an

installation of these shingles, approximately 25

years old. Figure 38 shows an installation of a new and attractive design of painted galvanized

shingle that is finding considerable use at the

present time. A large number of dwellings were

found around Savannah, Ga., where these

shingles had given satisfactory service for

periods up to 10 years, with little or no maintenance. A few cases were found, however, where

paint failure through peeling had occurred after

[17]
4 or 5 years. Instances of the buckling and

warping of isolated individual shingles of the

older stamped type were observed on some dwellings, caused either by faulty installation or by

movement of the sheathing boards.

The V-crimp type of galvanized roofing, even when unpainted, appears to give satis- factory service and the majority of installations are relatively free from imsightly corrosive

products which characterized the corrugated

material to a certain extent. While it is possible that this nuiy be due in some measure to the fact that the latter type preceded the

V-crimp material, it is not believed that it

is entirely a matter of age. Initial rusting was

found almost invariably on the top of the cor- rugations. Figures 39 and 40, respectively,

show installations of these two types of materials. Usually V-crimp roofing is installed over "open slat decks" or close-sheathed decks, with

recent practice calling for the use of asphalt

or asbestos felt laid over the latter type of deck.

High winds cause lifting from the deck of improperly secured sheets, with subsequent leakage. Also, considerable difficulty has been

experienced with some of the older designs of

V-crimp sheets from water that either blows

into or seeps through the joint, a condition

wiiich is said to be eliminated by recent methods

of holding the sheets together.

Many old roofs of standing-seam "roofing

tin," figure 41, were found in most sections.

Wliere properly protected by paint at all times

they give many years of service. A considerable number of flat-seam tin roofs were observed

at Birmingham, Ala., that had been given but

one recoating of paint since their initial installation some 10 or 12 years ago.

3. Flashings, Valleys, Gutters, and

Downspouts

These items, while of vital consideration in

the study of roofing materials, could not be

given detailed consideration in this survey be- cause of lack of time. It was practically impossible to secure definite information concerning the durability of the materials used for

flashings, valleys, gutters, and downspouts.

Some general observations follow:

(ff) Fla fillings

With the exception of Knoxville, Tenn., and

Charleston, W. Va., it was apparent that very

little attention was paid to cliimney and vent

flashings except on the more expensive dwellings

Figures 43 to 47 represent some typical installations of flashings which illustrate this point.

Figure 48 shows proper application of a metal

flashing, except that one section of the metal has

pulled loose from the chimney. Note the entire absence of chimney flashings in figure 7. Asphalt-prepared roll roofing, tin , galvanized

metal, and copper are all used for flashings.

The use of copper is very limited. Asphaltprepared roll roofing and "roofing tin" are used

most frequently with asphalt roll roofing and

sliingles and wood shingle roofs; galvanized

metal with galvanized sheet-metal and shingle

roofs.

(b) Valleys

Valleys, usually listed as "valley flashings," are constructed of the materials listed above,

"roofing tin" being used most frequently.

Mineral-surfaced roll roofings and tin are used

most frequently with asphalt shingle roofs

though a great number of valleys on roofs of

this type are formed by interlacing the butts of the asphalt shingles, as illustrated in figure 21. Copper is used with the more expensive roofing

materials. Galvanized metal is used almost

exclusively with galvanized sheet metal and

metal shingle roofs.

(c) Gutters and Dovmspouts

Most gutters and downspouts are constructed

of galvanized metal. Tin is used to a lesser extent, and copper infrequently, usually on the more expensive dwellings. In some cities,

notably Knoxville, Tenn., and Charleston, W.

Va., built-in, concealed gutters, lined with

"roofing tin," have been used extensively.

Gutters and downspouts are omitted in a

large percentage of the dwellings in the Southeastern States, particularly on dwellings of

moderate cost. They are used but rarely on

the cheaper dwellings in cities and in the rural

sections.

[18]
V. EXTENT OF USE OF THE VARIOUS

ROOFING MATERIALS IN URBAN

CENTERS OF THE SOUTHEASTERN

STATES

1. Factors Which Affect the Choice of

Roofing Materials Generally

Any discussion of the distribution of roofing

materials in a particular section of the country

should give some consideration to the factors

which influence the choice of these materials.

Unquestionably, cost is a deciding factor in

most cases. The first cost is influenced to a

considerable degree by nearness to sources of

supply and the cost of application of the material. Cost of maintenance is as important as

first cost and, with some types of roofing materials, may well exceed the first cost over the

period of the useful life of a roof. Fire resist- ance is another important consideration, most

cities having definite regulations concerning the

types of roofing materials that are permitted

within city limits; also, the cost of fire insurance

is greater with materials of lower fire resistance.

Finally, appearance has always been an important factor in the choice of a roofing material

and is apparently becoming increasingly more

important.

2. Factors Which Affect the Choice op

Particular Materials

That certain roofing materials, such as slate and ceramic tile, should have but slight use throughout the Southeastern States is readily

understood. They are classed definitely among

the more expensive materials, and their use is confined generally to the more expensive dwellings. This is proof that they are considered

satisfactory from the standpoint of appearance

and service.

Asphalt shingles are used more widely in

urban centers in the Southeast than any other

roofing material. They have been made readily available at a reasonable price in every

locality, and the cost of application has been

kept comparatively low. The cost of maintenance of an asphalt shingle roof is practically

negligible, in fact, manufacturers recommend

that no attempt be made to recoat weathered

asphalt shingles. They have come into their

greatest popularity during the period when

many of the cities have been prohibiting or

limiting the use of wood shingles, and thousands of dwellings have been reroofed with

asphalt shingles laid directly over weathered

wood shingles. The variety of colors has been a

strong factor in making them widely used.

Asphalt roll roofings, both smooth and mineral-surfaced, are less expensive than asphalt

shingles, and are used generally on dwellings of lower-cost construction.

Mineral-surfaced asphalt roll roofings made

to imitate the appearance of asphalt shingles are used to a considerable extent. Lines form.ed

by granules of contrasting color simulate the cut-out sections of shingles. See figure 24. Cement-asbestos shingles have not been used

to any considerable extent except in a few

locations. They are more expensive then

asphalt shingles and, like slate and ceramic tile, have been used most frequently on the more

expensive dwellings. At present, however,

they are being used more generally on all classes of dwellings.

Cement tiles are used to a considerable ex- tent in several cities where they are produced

locally. They require a very heavy roof structure so that the cost of a complete roof with

these materials is greater than with lighter

materials of about the same initial cost. Because of their weight, excessive freight rates

limit their distribution.

The use of wood shingles in urban centers

is practically negligible since every city either

prohibits them entirely or limits their use to certain areas. Insurance rates are higher on

dwellings roofed with wood shingles.

Metal roofs furnish an interesting study from

the standpoint of distribution. They have been

made readily available and, excepting such

materials as copper and zinc, have been priced

moderately, both as regards first cost and application. Galvanized iron and "roofing tin"

roofs require regular maintenance, but will render indefinite service if properly maintained. Apparently social influence and appearance have been strong factors in restricting

the use of metal roofings. Metal is used largely on the very cheapest dwellings in most southern

cities so that it has come to be classed as a cheap material. From the standpoint of appearance, there has been little to recommend it,

[19]
either in the various galvanized sheets or the

metal shingles that were produced formerly.

Improper methods of application rendered the

sheet roofings unsightly and the conventional

patterns of stamped shingles had little appeal.

More recently manufacturers of metal roofings

have been giving considerable attention to the

appearance of their products, so that today there

are produced sheet-metal roofs of low cost that

provide a very pleasing appearance, some in the

form of the ever-popular standing seam. Considerable progress has been made also with

metal shingles, some shingles that are now on

the market being practically indistinguishable

from slate. The popularity of these shingles

is shown by their use on dwellings costing up to $20,000 in the section where they are produced.

3. Distribution of Roofing Materials in

THE Cities Covered by This Survey

(a) Greensboro, N. C.

(1) New consirudion.—Asphalt shingles pre- dominate. One new development (built privately) of about 50 dwellings, ranging in price

from $5,000 to $7,000, was roofed entirely with

asphalt shingles. Some other dwellings costing

up to $12,000 were also roofed with asphalt

shingles.

Slate, tile, and cement-asbestos roofings are used on the more expensive dwellings.

One new apartment-type development, containing 86 apartments, and built at an average

cost of $5,400 per family unit, was roofed with

cement-asbestos shingles laid by the Dutch

lap method on the pitched sections and with a

five-ply coal-tar-pitch built-up roof, surfaced

with ground granite chips, on the flat sections.

(2) Old construction.—Most of the older

dwellings of medium cost were roofed originally

with wood shingles. Practically all of these

wood shingle roofs have been replaced or re- covered with asphalt shingles. In many cases individual asphalt shingles laid by the Dutch

lap or the hexagonal method have been used

for roofing directly over weathered wood shingles. Slate, tile, and cement-asbestos shingles

have been used chiefly on the more expensive

dwellings.

In the cheaper sections, sheet-metal roofings

predominate. In the cheapest dwellings these

were mainly V-crimp and corrugated sheets,

with some asphalt-prepared roll roofings and

asphalt sliingles. Several hundred dwellings

owned by a large textile company were all roofed with metal shingles of a conventional

design, painted with an aluminum paint over » red lead. A number of slate roofs, reported to be about

25 years old, were observed.

{h) Columbia, S. C.

(1) New construction.—Asphalt shingles pre- dominate. In one new subdivision of several

hundred dwellings of brick and stone construction, and ranging in price from $4,750 to $5,500, all the roofs were of asphalt shingles.

The use of slate, tile, and cement-asbestos

shingles is confined almost entirely to the more

expensive dwellings.

(2) Old construction.—Practically the same

conditions exist in Columbia as in Greensboro

that is, asphalt shingles have been used to replace or re-cover wood shingles which were

used formerly on most dwellings of medium

price. Some metal roofs, mostly standing-seam

sheets and shingles, were observed. Several

dwellings roofed with large tin shingles, illus- trated in figure 42, give the appearance of a standing-seam. roof. These are manufactured

in South Carolina and have not been distributed

widely.

On the cheapest dwellings, V-crimp and cor- rugated sheet metal roofings predominate, with some metal shingles, asphalt-prepared roll roofings and shingles. A few dwellings with

cement tile were observed.

(c) Savannah, Ga.

(1) New construction.—Savannah is a city

in which metal roofs definitely predominate.

Metal shingles are used widely on new construction regardless of price class. (See fig. 38.)

Some asphalt and cement-asbestos shingles

have been used on dwellings constructed re- cently, probably in about equal proportions.

(2) Old construction.—Most of the older metal

roofs in Savannah are of the standing-seam

type, painted, though metal shingles have been

used to a considerable extent. Cement-asbestos

shingles probably rank next to metal roofings in

[20]
number, having been imported in large quantities from Germany a number of years ago

and used on dwellings of every price class. Asphalt shingles have had comparatively little use. As elsewhere, a few slate and tile roofs were observed on more expensive dwellings.

In the cheaper sections, the roofs are largely

V -crimp and corrugated galvanized sheets. A few very old wood shingle roofs were observed.

(d) Jacksonville, Fla.

(1) New construction.—The wide variety of types of roofings on new construction in Jacksonville makes any estimate of the proportions

of the various kinds difficult. Probably asphalt

shingles have the greatest use, with cementasbestos and metal shingles being also used

widely. There are more tile roofs than in any

of the other cities visited. One slum-clearance project with apartmenttype buildings was inspected. Tliis development houses 215 negro families at a rental of from $2.90 to $4.55 per week. Low-pitched

roofs of interlocldng terra-cotta tile are used on

this project.

(2) Old construction.—The statement concerning the kinds of roofing materials on new

construction applies also to old construction.

Asphalt and metal shingles account for a large

proportion of the roofs in Jacksonville. Mineral

surfaced asphalt-prepared roll roofing, laid in

hot asphalt, on saturated felt nailed to board

sheathing, is used to a considerable extent. Some time was spent in Jacksonville in the

examination of a comparatively new roofing

material, 3-ounce copper backed up with a heavy paper or cardboard, and laid in long

sheets. It was reported that about 200 dwellings have been roofed with this material during

the past 2 years. It has been used chiefly for

reroofing.

(e) Orlando, Fla.

(1) New construction.—Practically all moderately priced dwellings that have been constructed in Orlando recently are roofed with

asphalt shingles. Some slate, tile, cementasbestos, and metal-shingle roofs were observed.

(2) Old construction.—Asphalt shingles have

been used very extensively, both as an original

roofing material and for reroofing over wood

shingles. Orlando was reported to have had a decided building boom about 12 years ago and

practically aU dwellings constructed at that

time were roofed with asphalt shingles. A few

old slate, tile, and cement-asbestos roofs were

observed.

Approximately 200 dwellings have been

roofed with thin sheet copper within the past 2

years. Most of these were reroofing jobs.

V-crimp and corrugated galvanized metal

roofings and asphalt-prepared roll roofings are divided about evenly in the cheapest sections of the city. Asphalt and metal shingles have had

slight use. A few old wood shingle roofs were

observed.

(/) Birmingham, Ala.

(1) New construction.—Asphalt shingles are used largely on dwellings of moderate cost, though metal roofings, a number of which are manufactured in Birmingham, are used to a

considerable extent. On more expensive dwellings constructed recently, colored slate and

shingle tiles are used extensively. Cement tile, manufactured in Birmingham, also has notable

use.Two Government low-cost housing projects were visited in the vicinity of Birmingham.

One contains about 300 4-, 5-, and 6-room detached dwellings of brick, frame, and shingle

construction, all roofed with one of the newer

types of galvanized sliingles. The other contained about 140 detached dwellings roofed

with redwood shingles.

(2) Old construction.—Asphalt shingles have

been used chiefly, both originally and for re- roofing.

Sheet metal, metal shingles, asphalt shingles,

and roll roofings are used extensively in the

lower-priced sections. One group of about

4,000 dwellings, all with metal roofs, is under

single management. A few old wood shingle

roofs were observed.

{g) Atlanta, Ga.

(1) New construction.—Dwellings of moderate price are practically all roofed with asphalt

shingles. Two recent developments were observed, comprising several hundred dwellings,

all roofed with asphalt-strip shingles. One

[21]
group ranged in price from $2,500 to $4,000,

the other from $4,500 to $8,000.

Colored slate is used quite extensively on the more expensive dwellings. Tile and cementasbestos shingles are used to a limited extent.

(2) Old construction.—The striking feature

of roofing in Atlanta is the very extensive use

of roll roofing on older dwellings. It is used

principally for reroofing and is not confined to any particular price class, but in sections whole

blocks of dwellings of moderate price are roofed

with this material. The roll roofing is laid

vertically from ridge to eaves on most reroofing

jobs. Workmanship on these roofings seems

to have been particularly good in Atlanta. See

figures 26 and 27. Several developments built from 10 to 15

years ago were roofed entirely with asphalt

shingles.

A considerable number of old slate roofs were

noted. Many of these had weathered to a rusty brown color and were reported to be of

slate produced from the Rockmart quarries in

Georgia. Metal roofings are not used to any

considerable extent in Atlanta. When metal

is used it is mainly on the cheaper dwellings.

Probably the popularity of roll roofing is re- sponsible for the limited use of metal.

Practically no wood-shingle roofs were observed.

Qi) Knoxville, Tenn.

(1) New construction.—Asphalt shingles are used most frequently, though a number of new

dwellings that were roofed with cementasbestos shingles were observed. All of the

291 dwellings in the town of Norris, about 25

mUes from Knoxville, built to house the families

of men who built Norris Dam, are roofed with

wood shingles.

(2) Old construction.—Asphalt shingles have

had wide use in Knoxville, probably more than

any other single material, on new construction

and as a reroofing material. Numerous slate roofs from 25 to 50 years old and many wood

shingle roofs were observed, probably more of

these, all old, than in any other city visited.

A few metal roofs were seen, mostly standing- seam sheets and the older conventional type

metal shingles.

In the cheapest sections asphalt roll roofing

and sheet metal predominate.

(i) Charleston, W. Va.

(1) New construction.—Asphalt shingles are used most extensively on moderately priced

dwellings. About 300 dwellings in one new

development and about 40 in another, are roofed almost entirely with asphalt shingles.

Slate and ceramic tile are also used to a considerable extent on more expensive dwellings.

Apparently cement-asbestos and metal roofings are but slightly used.

One group of about 150 low-cost dwellings,

located about 35 mUes from Charleston, built

recently by the Federal Government, is roofed

entirely with asphalt shingles.

4. Summary of Extent of Use of the Vari- ous Roofing Materials in Urban Centers

IN THE Southeastern States

(a) New Construction

Apparently from 50 to 75 percent of all dwellings constructed recently in the cities visited are roofed with asphalt strip shingles,

and it is probable that the larger figure is more

nearly the correct one. Apparently cementasbestos shingles and metal shingles are in- creasing in use, as are cement tUes. Slate and

heavy ceramic tiles are confined largely to the more expensive dwellings.

(b) Old Construction

Wood shingles, chiefly cypress and pine, apparently predominated in these cities before the

advent of asphalt shingles. Most dwellings

that were roofed originally with wood shingles are now roofed with asphalt shingles, frequently

laid over the weathered wood shingles. Metal

shingles of the older types have been used to a considerable extent, also standing-seam metal

roofs, on dwellings of moderate price. The

[22]
less expensive forms of galvanized nietal roofings are used on dwellings of lower cost in about the same quantities as asphalt roll roofings and shingles.

Slate and tile roofs account for a relatively

small percentage of the total number. Slate was apparently used more often in former years on dwellings of moderate cost. Cement-asbestos shingles have been used to the greatest extent in seaport cities such as Savannah, Ga., and Jacksonville, Fla., large

quantities of these shingles having been shipped

to these cities.

5. Costs of Roofing Materials, Including

Cost of Application, in Urban Centers

IN THE Southeastern States

The price, including cost of application, per

square (100 sq. ft. of roof surface) for each of the

materials listed in table 3 was furnished by

representatives of the Home Owners' Loan Corporation in Greensboro, N. C, Columbia, S. C,

Savannah and Atlanta, Ga., Jacksonville, Fla.,

Birmingham, Ala., and Knoxville, Tenn. The

range is shown in the columns marked "maximum" and "minimum." The maximum and

minimum costs were distributed among the

different cities and w^ere not confined to any

particular one. The average cost shown is the

average for all of the cities.

Table 3.Costs of roofing materials and application, per square, on a simple pitched roof with no valleys, but including chimney flashings

[Data obtained from the Home Owners' Loan Corporation)

Materials

Asphalt shingles: Giant individual, 12"X1G", American metiiod Standard individual, 9"X12?4", American metiiod

4-tab square butt strip, 12H"X

36"

3-tab square butt strip, 12"X

36" overlay

2-tab hexagonal strip, lli/^"X36". Individual recover—Dutch lap... Individual recover—hexagonal. .

Asphalt roll roofing: Mineral-surfaced. Smooth-surfaced

Cement-asbestos shingles {gray color only)

American method

llexasonal method Dutch lap

Slate Wood shingles- Metal roofings: Shingles (galvanized) Five V-crimp sheets (galvanized) Standing seam "tin" 25 lb., unpainted

Flat lock and soldered "tin", 25

lb., unpainted —

Tile roofing: Ceramic shingle tile- Cement tile

Built-up roofing: Five-ply coal-tar-pitch, surfaced with slag or gravel Five-ply asphalt, surfaced with

slag or gravel

Weight

per square

Pounds

325

255

266

211 167

125 to 140

125 to 140

Cost per square

Mini- mum

.$9. 50

8. 25

8. 25

6. 75

5. 25

5. 25

5. 25

3. 00

2. 50

13. 75

9. 50

10. SO

14.00

6. 00

7. 50

6. 00

8. 25

9. 25

14. 40

14. 00

6. 75

7. CO

Maxi- mum

.$14. .50

13. 50

10. 40

9. 10

7. 15

6. 90

6. 80

6.50

5. 90

24. 00

15. 25

16. 75

40. 00 15.00

12.50

7. 15

14. 00

15. 00

30. 00 22.50

12. 00

12.00

Average

$10. 05

9. 45

9.00

7. 95

6. 35

5. 85

5. 90

4. 35 3.55

19.00

12. 35

13. 00

21.00

9. 15

9.05

6. 40

11. 70

12.80

20.20

16.75

9.55

9. 65

o

[23]

The National Bureau of Standards was established by act of Congress, approved

March 3, 1901, continuing the duties of the old Office of Standard Weights and Measures

of the United States Coast and Geodetic Survey. In addition, new scientific functions were assigned to the new Bureau. Originally under the Treasury Department, the

Bureau was transferred in 1903 to the Department of Commerce and Labor (now the

United States Department of Commerce). It is charged with the development, construction, custody, and maintenance of reference and working standards, and their

intercomparison, improvement, and application in science, engineering, industry, and

commerce. SUBJECTS OF BUREAU ACTIVITIES

Electricity

Resistance Measurements

Inductance and Capacitance

Electrical Instruments Magnetic Measurements

Photometry

Radio

Underground Corrosion

Electrochemistry

Telephone Standards

Weights and Measures Length

Mass

Time

Capacity and Density

Gas Measuring Instruments Thermal Expansivity, Dental

Materials, and Identification Weights and Measures Laws

and Administration

Large Capacity Scale Testing

Limit Gages

Heat and Power Thermometry

PjTometry

Heat Measurements Heat Transfer Cryogenics

Fire Resistance Automotive Power Plants Lubrication and Liquid Fuels

Optics

Spectroscopy

Polarimetry

Colorimetry and Spectrophotometry

Optical Instruments Radiometry

Atomic Physics, Radium, and

X-Rays

Photographic Technology

Interferometry

Chemistry

Paints, Varnishes, and Bitu- minous Materials Detergents, Cements, Corrosion, Etc.

Chemistry—Continued

Organic Chemistry

Metal and Ore Analysis, and

Standard Samples

Reagents and Platinum Metals

Electrochemistry (Plating)

Gas Chemistry

Physical Chemistry

Thermochemistry and Constitution of Petroleum

Mechanics and Sound

Engineering Instruments and

Mechanical Appliances

Sound

Aeronautic Instruments Aerodynamics

Engineering Mechanics

Hydraulics

Organic and Fibrous Materials Rubber

Textiles Paper

Leather

Testing and Specifications Fiber Structure Organic Plastics Metallurgy

Optical Metallurgy

Thermal Metallurgy

Mechanical Metallurgy

Chemical Metallurgy

Experimental Foundry

Clay and Silicate Products Whiteware

Glass

Refractories Enameled Metals

Heavy Clay Products

Cement and Concreting Materials Masonry Construction

Lime and Gypsum

Stone

Simplified Practice Wood, Textiles, and Paper

Metal Products and Construction Materials

Simplified Practice—Continued

Containers and Miscellaneous

Products

Materials-Handling Equipment and Ceramics

Trade Standards Wood, Wood Products, Paper,

Leather, and Rubber

Metal Products

Textiles Apparel

Petroleum, Chemical, and Miscellaneous Products

Codes and Specifications

Safety Codes

Building Codes

Building Practice and Specifi- cations Producer Contacts and Certification Consumer Contacts and Labeling

Office Finance

Personnel Purchase and Stores Property and Transportation

Mail and Files liibrary

Information

Shops Instrument Woodworking

Glassblowing

Construction Stores and Tool

Roojn

Operation of Plant Power Plant

Electrical Piping

Grounds

Construction

Guard

Janitorial