NATIONAL

BUREAU OF STANDARDS
The program of resefl-rch on building materials and structures, carried on by the

National Bureau of Standards, was imdertaken with the assistance of the Central Housing Committee, an informal organization of goveminental agencies concerned with

housing construction and finance, which is cooperating in the investigations through a

committee of principal technicians.

CENTRAL HOUSING COMMITTEE , , >ii ON RESEARCH, DESIGN, AND CONSTRUCTION r ,

A. C. Shire,. Chairman. * Howard P. Vermilya, Vice Chkirman}

' i Uhited States Housing Authority. Federal Housing AdministiPatioh. -

; Steiiling. R. March, Secretary.

Ma-ry F. Taylou, Assistant Secretary.

Pierre Blouke, ' ' John F. Donovan, ^ Federal Home Loan Bank Board. Farm Seciirity Administration.

Hugh L. Dryden, George W. Trayer,

National Buresau of Standards. ; Forest Service (F. P. .Laboratory).

Louis A. Simon, . Rolla H. Britten, > Pubhc Buildings Administration. PubUc Health Service.

Luther M. Leisenring, George E. Knox,'!

' 'Construction , Division (War). Yards and Docks (Navy).

Edward A. Poynton, William R. Talbott,

Office of Indian Affairs. . Veterans' Administration.

, Wallace Ashby,

Bureau of Agricultural Chemistry and Engineering.

NATIONAL BUREAU OF STANDARDS

STAFF COMMITTEE ON ADMINISTRATION AND COORDINATION

Hugh L. Dryden, Chairman.

Mechanics and Sound.

Phaon H. Bates, Gustav E. F. Lundell,

Clay and SUicate Products. Chemistry.

Hobart C. Dickinson, Addams S. McAllister,

Heat and Power. Codes and Specifications.

Warren E. Emley, Henry S. Rawdon,

Organic and Fibrous Materials. Metallurgy.

The Forest Products Laboratory of the Forest Service is cooperating with both

committees on investigations of wood constructions.

[For list of BMS publications and directions for purchasing, see cover page in]
UNITED STATES DEPARTMENT OF COMMERCE • Jesse H. Jones, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS75

Survey of Roofiny; Materials in the North Central States

by

HUBERT R. SNOKR dfiol LRO J. WALDRON

ISSUED JULY 1, 1941

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

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

UNITED

FOR SALE

STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • I 94 I

BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE I5 CENTS
Foreword

This report is the thiixl of a seiies issued by the Na tional Bureau of

Standards on surveys of the weathering quahties and extent of use of

roofing materials in different sections of the country.

Reports published previously are: BMS6, Survey of Roofing

Materials in the Southeastern States, and BMS29, Survey of Roofing

Materials in the Northeastern States. The present paper describes

the results of a similar survey in the North Central States. Frequent

reference is made in this report to the reports on previous surveys.

A tabulation, by States, of the kinds of roofing materials that were

found on more than 8,000 rural and small-town dwellings, along approximately 3,000 miles of highway in the North Central States, is included; also, a summation of the kinds of roofing used on almost

29,000 dwellings along more than 7,000 miles of highway in the 32

States covered by the 3 surveys.

More than 400 photographs, showing types of weathering of roofing

materials, and features of design and construction, were taken in the

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

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

by HUBERT R. SNOKE and L¥,0 J. WALDRON

CONT

Page

Foreword ii

I. Introduction 1

II. Methods of making the survey 2

III. Extent of use and appearance of the vari- ous roofing materials in rural districts and small towns in the North Central

States - 3

1. General 3

2. Routes followed in making the survey 3

3. Extent of use of particular materials

in rural sections 3 IV. Weathering qualities of roofing materials

in the North Central States 4

1. General discussion 4

2. Discussion of particular materials _ _ 5

(a) Asphalt shingles and roll roof- ings 5

(b) Wood shingles 8

(c) Cement-asbestos shingles 11

(d) Slate 13

(e) Built-up roofing 14

(f) Tile 15

(g) Metal 17

E N TS

Page IV. Weathering qualities of roofing materials

in the North Central States—Con.

3. Flashings, valleys, gutters, and

downspouts 17

(a) Flashings 17

(b) Valleys 17

(c) Gutters and downspouts 17

V. Extent of use of the various roofing materials in urban centers in the North

Central States 18

1. Factors which affect the choice of roofing materials generally 18

2. Distribution of roofing materials in the cities included in this survey _ 18 VI. Roofing costs in urban centers in the North Central States 18

VII. Summary 19

1. Distribution 19

2. Weathering 19 VIII. Selected references 20

1. Asphalt shingles and roll roofings. _ 20

2. Wood shingles 20

3. Cement-asbestos shingles 20

4. Slate 20

5. Tile 20

6. Metal 20

7. General, including built-up roofing. 20

ABSTRACT

A survey of the weathering qualities and extent of use of the various roofing materials on dwellings in the North Central States is described, with numerous refer- ences to similar surveys made previously in the Southeastern and Northeastern States. Detailed studies of roofing materials in Pittsburgh.

Pa.; Cincinnati and Toledo, Ohio; Grand Rapids and

Lansing, Mich.; Chicago, lU.; Milwaukee, Wis.; St. Paul, Minn.; Bismarck, N. Dak.; Sioux Falls, S. Dak.;

Omaha, Nebr. ; Kansas City, Moberly, and St. Louis, Mo.; and Indianapolis, Ind., are reported.

A tabulation, by States, of the kinds of roofing materials used on more than 8,000 rural and small-town

dwellings, along approximately 3.000 miles of highwaj'

between the cities listed above, is included; also a summary of the kinds of roofing materials used on almost 29,000 rural and .small-town dwellings along 7,000

miles of highway in the 32 States covered by the three surveys. Forty-eight photographs, illustrating type 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, comprehensive snrveys

of the various types of roofing materials used in locations typical of widely differkig climatic

conditions in the country.

317834°—41 [1]
The first of these surveys, made in April 1938,

covered the following States: Virginia, North

and South Carolina, Georgia, Florida, Alabama,

Tennessee, Kentucky, and West Virginia.

Another survey, made in September and October 1938, covered Delaware, Pennsylvania,

Connecticut, Massachusetts, New Hampshire,

Maine, Vermont, and New York. The results

of these surveys have been published, respectively, as Building Materials and Structures

Report BMS6, Survey of Roofing Materials

in the Southeastern States,^ and Building Materials and Structures Report BMS29, Survey

of Roofing Materials in the Northeastern

States.^ The present report described a similar survey

in the following cities: Pittsburgh, Pa.; Chicago, 111. ; Milwaukee, Wis. ; St. Paul, Minn.

;

Toledo and Cincinnati, Ohio; Lansing and

Grand Rapids, Mich.; Bismarck, N. Dak.;

Sioux Falls, S. Dak.; Omaha, Nebr. ; Kansas

City, Moberly, and St. Louis, Mo.; and

Indianapolis, Ind. It includes also a re- port on the extent of use of the different roofing

materials, classified roughly by appearance, on

rural dwellings along the highways between the

cities visited. This survey was made from

August 12 to September 24, 1940, and involved

approximately 4,600 miles of travel. Reference to the previous surveys is fre- quently made in this report. For convenience,

the survey in the Southeastern States is referred

to as BMS6 and that in the Northeastern States

as BMS29.

Another report. Building Materials and

Structures Report BMS57, Roofing in the

United States—Results of a Questionnaire,^

summarizes the replies to a questionnaire on

general roofing practices and conditions

throughout the entire country, furnished by

representatives of the Home Owners' Loan

Corporation and Federal Housing Administration in 48 States and the District of Columbia.

This report is referred to as BMS57.

Space is not available in this report to deal

at length with the history, methods of production, composition, etc., of the various kinds of

' Price 15 cents. See cover page m.

2 Price 10 cents. See cover page III.

' Price 10 cents. See cover page IV,

roofing materials. A list of selected references

to the literature on roofing materials is given

at the end of the report.

II. METHODS OF MAKING THE

SURVEY

The methods of making this survey, insofar as they concerned weathered roofing materials, were essentially the same as those followed in the two previous surveys. They are discussed

in detail in BMS6 and BMS29, so that only a

brief outline is necessary here.

All travel was by automobile. A count was made of the roofs on rural dwellings along the

highways traveled (reported in table 2) and

the kind of roofing materials used.

As in the previous surveys, local representatives of the Home Owners' Loan Corporation

assisted in collecting data on roofs of different

kinds and known history. Many of these representatives had spent considerable time in

work preliminary to this survey, and had pre- pared lists of roofs that included all kinds of

materials.

The offices of the Federal Housing Administration were visited in Pittsburgh, Pa.; Milwaukee, Wis. ; Omaha, Nebr. ; Kansas City and

Saint Louis, Mo.; and Indianapolis, Ind. The

problems and practices in the use of roofing

materials on new construction were discussed

with representatives of this organization and

new developments were inspected.

General roofing policies and practices were

discussed with men in the Division of Agricultural Engineering at Michigan State College

and the University of Minnesota. The Forest

Products Laboratory at Madison, Wis., was

also visited. Plants manufacturing roofing materials were

visited in Minneapolis, Minn.; Cincinnati,

Ohio ; and Moundsville, W. Va.

Acknowledgment is made to all who fur- nished assistance in this work, particularly to representatives of the Home Owners' Loan Corporation to whom had been assigned the preparatory work in each city; and to the numerous

roofing contractors who furnished trucks and

ladders, without which it would have been impossible to conduct the investigation.

[2]
III. EXTENT OF USE AND APPEARANCE OF THE VARIOUS ROOFING

MATERIALS IN RURAL DISTRICTS

AND SMALL TOWNS IN THE NORTH

CENTRAL STATES

1. General

A wide range in roofing materials in rural

districts and small towns characterizes the

territory covered by this survey. Availability of materials and climatic conditions apparently are the chief governing factors. In

Maryland, Pennsylvania, and Ohio, which are

relatively close to slate-producing districts, slate has been used widely in the past, but more

recently asphalt shingles have largely superseded this material.

Throughout the rural sections of Michigan,

Indiana, Illinois, and Missouri, wood shingles

predominated formerly, and are still used to a

considerable extent, although asphalt shingles

and roll roofings are now used to a greater ex- tent than wood shingles. Considerable quantities of diamond-point and fancy-patterned

roll roofings are used in these states as a re- roofing material over weathered wood and

asphalt shingles. Individual shingles laid by

the Dutch-lap, hexagonal, and wide-space methods, which are used frequently for reroofing

along the Eastern Coast, have practically no

use in this territory.

In the sections of Wisconsin, Minnesota,

North and South Dakota, Iowa, Nebraska, and

Kansas, that were visited, wood shingle roofs

outnumber all other types. This is particularly true of the rural sections and small towns

in North and South Dakota. In traveling

from Bismarck, N. Dak., to Sioux Falls, S. Dak.,

by the routes listed in table 1 , 564 wood shingle

roofs were counted in 369 miles with no roofs

of any other type.

2. Routes Followed in Making the Survey

Table 1 lists the cities in which studies were made and the routes between cities in the

order they were traveled.

Table 1.

Routes traveled in making thifs survey

Cities Routes '

WashinKton, D. C, to PitlshiirRh, Pa

Pittsburgh, Pa., to Tolc<l(i, Ohio

Toledo, Ohio, to Grand Uaijiils, Mich

Grand Rapids, Mich., to Chicago, 111 Chicago, 111., to Milwaukee, Wis

Milwaukee, Wis., to St. Paul, Minn

St. Paul, Minn., to Bismarck, N. Dak

Bismarck, N. Dak., to Sioux Falls, S. Dak.

Sioux Falls, S. Dak., to Omaha, Nebr Omaha, Nebr., to Kansas City, Mo ._- Kansas City, Mo., to Moberly, Mo__

Moberly, Mo., to St. Louis, Mo . St. Louis, Mo., to Indianapolis, Ind_

Indianapolis, Ind., to Cincinnati, Ohio

Cincinnati, Ohio, to Wheeling, W. Va.. - Wheeling, W. Va., to Washington, D. C„^

240, 16, (Ifi), (316), 30. (356), 422, 224, 20. 223, 127, in. (21), 31, 20.

41.

18, 12. 52, 10. 10,83, 12, 281,212,81, 14,77.

77, 75, (). 73. 40. 24. 63, (22), 54, (19), 40.

40.

52. 22, 40.

40, 240.

1 state highways in parenthesis; all others are U. S. highways. A map of the territory covered is shown in

figure 1.

3. Extent of Use of Particular Materials

IN Rural Sections

In table 2 are tabulated, by States, the kinds

of roofing materials used on dwellings in

the rural sections along the routes listed in

table 1. The condition of each kind of rural roof was

classified roughly as "good" or "poor", this classification being based entirely on appear- ance and, in most cases, made by observation

from the highway of only one side of the

roof.

[3]
Table 2.

Roofing materials in rural sections of States traversed

[The general condition of the roof is indicated as "good" or "poor"]

Asphalt

shingles Wood

shingles

Slate Sheet metal

Roll

roofing Cementasbestos Metal

shingles Tile

state

Good 1

Poor

Total

i

O

Oo

Poor 1

1

1

Total

1

j

Good j

Poor 1

Good Poor

Total Good 1

Poor

Total j

Good Poor [

Total Good {

Poor 1

Total Good Poor

Total

Tota!

Maryland _ . 177 12 189 15 27 42 46 7 53 167 29 196 33 29 62 25 1 26 27 5 32 1 0 1 DUl Pennsylvania . 327 35

61

362 12 19 31 262 60 96 50 146 66 96 162 56 1 57 4 10 14 1 09^ Ohio.. ... 427 488 127 86 213 674 25 699 203 59 262 31 29 60 61 0 61 1 1 2 2 0 2 1 787 Michigan .. 35fi 18724

0

4

71

73

427 227 63

69

290 7 0 7 37 16 53 59 49 108 12 0 12 897

'^Visconsin. 194 461 530 38 7 45 30 30 60 6 0 6 1 0 1 83( Minnesota. 27? . 27 207 22 229 13 4 17 North Dakota . 1

1

1 201 93 294 1 1 2 1 0 1 29i South Dakota 5 525

107

90 615 1 3 4 624

1530

35

153

5 20 18 12596

8 5 13 1 0 1 1 0 1 160 Nebraska - 3 33 56 40 5 2 7 2 0 2 1 0 1 139 Kansas. .. 12

45

47 19890

77

40 130 2 0 2 5 2 7 186 Missouri 110 187 2 0 2 28 8 36 14 27 41 2 0 2 1 0 1 467

Illinois. 104

129

23

11

187

140

31 90 121 1 0 1 11 4 15 35 27 62 15 0 15 401 Indiana.. . . ... 74 81 155 10 5 15 24 10 34 13 10 23 7 1 8 2 1 3 378

Totals 2. 028 290 2,318 2, 210 848 3, 058 1.002 97 1,099 606 183 789 314 314 628 187 3 190 38 17 55 4 0 4 8, 141

The counts of rural roofs in the three surveys

to date are summarized in table 3. Table 3.

Summary of counts of roofs in rural sections

[Miles traveled; Southeast 2,447, Northeast 1,591, North Central 3,014, Total 7,052]

Type of roofing material

Sheet metal

Asphalt shingle.... Roll roofing Wood shingle Metal shingle Cement-asbestos.

.

Slate Tile Thatched

Total.

.Average number

of roofs per mile.

Southeast

No.

3, 722

2, 558 1,982

1,757

366

184

6444

10, 677

Per- cent I

34.9 24.0

18. 6 16.5 3.4

1.7.6.4

Northeast North Central

No.

1,006

3,991

399

2, 779

134 284

1, 546

23

2

10, 164

6 4

Per- cent I

39.3

3.9 27.3

1.3 2.8

15.2

.2

No.

789

2, 318

628

3, 058

55

190 1,099

4

8, 141

2.7

Per- cent 1

9.7

28.4

7.7 37.6

. 7 2.3

13.5

Total

No.

5, 517 8,867

3, 009 7,594

555 658

2, 709

71

2

28, 982

Per- cent

19.0

30. 6 10.4

26. 2

1.9 2.3 9.3

.2

I'ercentage based on the particular survey.

It was noted in BMS29 that approximately

76 percent of the rural roofs in the sections

covered by the first two surveys were asphalt

shingles, wood shingles or sheet-metal.

It is significant that the total percentages of roofs of these three materials are approximately the same for the three surveys to date,

although the proportions of each kind vary

widely in the different sections of the country.

The total percentages of these three materials

are as follows: Southeast, 75.4 percent; Northeast, 76.5 percent; North Central, 75.7 percent;

and for the combined surveys, 75.8 percent.

IV. WEATHERING QUALITIES OF ROOFING MATERIALS IN THE NORTH

CENTRAL STATES

1. General Discussion

In the reports of the previous surveys, BMS6

and BMS29, it is stated that "Any discussion

of the weathering qualities of roofing materials

in a particular section must, of necessity, be

couched in the most general terms." In these

reports are discussed some of the important

factors w^hich have to be considered in studies

of the weathering qualities of roofing materials.

1. Weather conditions during and after construction.

2. Influence of the pitch and exposure of a roof on the w^eathering of the roofing material.

3. Workmanship in applying the roofing

material.

4. Varieties of materials, and variations in

the design and quality of materials of the same

kind.

5. Absence of definite criteria for determining

when a roofing material has failed. Essentially the same roofing materials are used in dift'erent sections of the country, but

the dift'erences in climate between sections are

refiected in differences in roofing practices. In

ai'eas where there is much snow, roofs are usually steeply pitched. Wood-shingle roofs

have wide use in regions of extreme cold, be-

[4]
cause of theii' insulating value. In regions

where snow may be accompanied by high winds,

wood shingles are always laid on closed decks

rather than on shingle lath, and frequently a

layer of sheathing paper or saturated felt is placed between the sheathing boards and the

shingles.

It does not always follow that similar conditions in two areas will produce the same

roofing practices in both. Throughout the New

England States the practice of using a wide

metal or roll roofing eaves strip with shingletype roofs is quite common. This practice was

not observed in any of the North Central States,

although the weather conditions in some of these states are as severe as in New England.

In subsequent sections the weathering charactei'istics of the roofing materials that are used

principally in the North Central States are discussed and, wliere possible, are illustrated by

means of photographs. No attempt has been

made in this discussion to differentiate between

brands of roofing materials.

2. Discussion of Particular Materials

(a) Asphalt Shingles and Roll Roofings.

It was observed in the previous surveys that

asphalt-prepared roofings weather less rapidly

in the Northern than in the Southern States,

the difference in a material between the two

areas being mainly one of degree rather than of the kind of weathering. These observations were confirmed in the present survey. During

this survey some asphalt shingles were found

that were older than any previously seen, and

probably as old as any in the country. Asphalt

shingles were first manufactured regularly in Grand Rapids, Mich., about 1910 or 1911.

Figures 2 and 3 illustrate roofs in Grand Rapids

and Zeeland, Mich., respectively, that were

reported to have been in use since 1911. These

roofs were both of individual shingles applied

by the American metliod. The shingles were made on a comparatively heavy felt base and

with a thiclv asphalt coating that permitted a

large quantity of mineral surfacing material.

When examined they were quite brittle. Several shingles in figure 2 have been broken, but a very considerable part of the granular surfacing

has been retained. Figures 4 and 5 illustrate the northern and southern exposiiix's, respectively, of a roof composed of similar shingles

after exposure of approximately 27 years in Grand Rapids.

It should be noted in iigures 2 and 3 that the

shingles are laid so that the spaces between

shingles in one course are placed in the center

of the shingles in the next course below. This was the first method used for the application of individual shingles. Figures 4 and 5 illustrate a method that was developed later, in which

the space between two adjacent shingles is placed to one side of the center of the shingle in the next course below. Shingles laid by both of

these methods provide three layers of fabric over the greater part of the roof area. With

those laid as in figures 2 and 3, a small part of the area is covered by only a single layer of

fabric, v/hereas with the method illustrated in

figures 4 and 5 no part is covered by fewer than

two layers.

No attempt has been made to estimate the

probable useful life of asphalt shingles in the

North Central States. The shingles are marketed in many different weights and designs

and are subject to so many other variables that

any general estimate would be meaningless.

However, some decided variations were noted

in the weathering of shingles in difl"erent sec- tions of this territory. An attempt has been

made to illustrate some of these variations by

photographs of individual asphalt shingles laid by the Ameiican method in different locations.

Each of these illustrations has been chosen to indicate an approach to the maximum rather

than the minimum service that can be expected.

Invariably, the asphalt shingles having the

longest service life that have been observed

in any locality have been individual asphalt

shingles laid by the American method.

Figures 2 to 5, already discussed, are roofs

m Grand Rapids and Zeeland, Mich., after 29

and 27 years of exposure. Other illustrations,

with the location followed by the number of years of exposure are figure 6, Pittsburgh, Pa.,

20 years; figure 7, Toledo, Ohio, 24 years;

figures 8 and 9, northern and southern exposures, respectively, Milwaukee, Wis., 20 years;

figure 10, Omaha, Nebr., 20 years; figure 11, St. Louis, Mo., 17 years; figure 12, India-

[5]
FiGUHEs 2 to 7.

Atipliull .shuiylr.s (individual shingles applied hij the American method).

Figures 2 and 3, exposed 29 years in Grand Rapids and Zealand, Mich., respectively; 4 and 5, northern and southern sections, respectively, of a

roof after approximately 27 years of exposure in Grand Rapids, Mich.; 6, exposed 20 years in Pittsburgh, Pa.; 7, exposed 24 years in Toledo, Ohio.

napolis, Ind., 18 years; figure 13, Cincinnati,

Ohio, 16 years. The same types of weathering were observed

in this as in the previous surveys. Shingles

and roll roofings under normal weathering retain their mineral surfacing granules for long

periods. Eventually, however, oxidation of

the asphalt coating in which the granules are embedded lessens the bond between the coat- ing and granules. The mechanical action of

6]
r

10

Figures 8 to 13.Asphalt shingles {individual shingles applied by the American method).

Figures 8 and 9, northern and southern sections, respectively, of a roof after 20 years of exposure in Milwaukee, Wis.; 10, exposed 20 years in Omaha,

Nebr.; 11, exposed 17 years in St. Louis, Mo.; 12, exposed 18 years in Indianapolis, Ind.; 13, exposed 16 years in Cincinnati, Ohio.

rain, snow and wind assists in removing the

granules. Wlien they begin to disappear, the

weathering process is accelerated because the

asphalt coating weathers more rapidly when

317s:«° 41 2

exposed directly to the sunlight than when it

is protected by the granides.

Prepared roofings and shingles that have been

exposed for long periods become quite hard and

[7
brittle, mainly owing to oxidation of the as- phalt coating and saturant. Most of the

shingles illustrated in figures 2 to 13 were very

brittle. This is not objectionable, provided

they are not subjected to high winds which

may break the tabs, as shown in figure 3. Very little blistering of asphalt coatings was

observed in the northern cities of the territory

covered by tliis survey but in Kansas City,

St. Louis, Indianapolis, and Cincinnati, this

feature was observed.

Asphalt shingles and roll roofings have had

very wide use in the cities covered by this sur- vey, with the exception of Bismarck, N. Dak.,

and Sioux Falls, S. Dak. As in other territories

they have been used to a considerable extent as reroofing materials over wood shingles. Individual shingle roofs laid by the Dutch lap,

hexagonal and wide-space methods, which are reroofing methods, are not used nearly so commonly as m the northeastern and southeastern sections.

Mineral-surfaced roll roofings with the ex- posure edge cut to form a pattern when the

roof is laid are used to a much greater extent,

however. These are usually 18 inches wide

and are used only for reroofing. The most

common is the diamond point roofing, with a

serrated edge, as illustrated in figure 14. Note

m this illustration that the roofing weathered

most where it was bent slightly in conformity

with the butts of the wood shingles underneath.

In general, mineral-surfaced roll roofings do

not give as long service as asphalt shingles,

mainly because they provide but a single layer

of fabric over the greater part of the roof area. As with asphalt sliingies, roll roofings older

than any seen in the previous surveys were

observed in this one. A few of these are illus- trated in figures 15 to 18. These have also been

chosen to illustrate an approach to the maximum service that may be expected: Figure 15,

Toledo, Ohio, 20 years; figure 16, Milwaukee,

Wis., 20 years; figure 17, Omaha, Nebr., 12

years; figure 18, Moberly, Mo., 12 years;

figure 19, Milwaukee, Wis., 19 years. All of these were applied over wood shingles. The

roofings in figures 16 and 18 show damage

caused by hailstones.

Asphalt shingles are used to a great extent on

low-cost housing projects ravolving singlefamily dwelhngs. On those financed with

loans insured by the Federal Housing Administration, the shingles must weigh at least 210

pounds per square applied.

(6) Wood Shingles

Many more roofs of wood shingles were observed in the territory covered b}^ this survey

than in those of the previous ones. The census of rural roofs showed wood shingles to be the pre- dominating roofing material in 8 of the states included in the survey, and in the whole rural

survey more roofs of wood shingles were observed than of any other kind. The wide use

of wood shingles is readily explained . Throughout the greater part of this territory they were

used almost exclusively up to about 25 years

ago. Michigan, Wisconsin, and Minnesota produced great quantities of wood shingles, and in

these states, as in the Dakotas, their ready

availability and adaptability to the climatic

conditions promoted their wide use. Their use

in built-up areas has been limited by fire regulations. Most large cities have adopted regulations forbidding the use of wood shingles

within certain fire zones. Some cities have

established three kinds of zones; the first re- quiring fireproof roofing materials; the second,

fire-resistant materials; and the third, unrestricted.

Practically all of the wood shingles used at present in the territory covered by this survey

are of western red cedar, which is very resistant

to weathering. They are almost invariably

applied on a tight sheathing deck in locations

subject to severe winters accompanied by much

snow. The sheathing provides additional heat

insulation and prevents the infiltration of

finely powdered snow during high winds. In

Omaha, Kansas City, St. Louis, Indianapolis,

and Cincinnati, wood shingles are usually

applied on spaced sheathing. No appreciable

difference has been noted in the rate of weathering of those applied on shingle lath and on

tight sheathing. It is believed that shingles

of the proper size and grade will render

satisfactory service when applied by either

method.

The greatest differences that have been noted

in the weathering of wood shingles have not

[8]
Figures 14 to 19.

Minerals urfaced, asphalt-prepared roll roofings.

Figure 14, diamond-point roofing: 15, exposed 15 years in Toledo, Ohio; 16 and 19, exposed 20 and 19 years, respectively, in Milwaukee, Wis.; 17, exposed 32 years in Omaha, Nebr.; 18, exposed 12 years in Moberly, Mo.

been due to climatic conditions but rather to differences in the quahty or grade of the

slimgles. Intense competition and disregard of proper

grading rules, for a number of years has resulted

in the wide distribution of inferior shingles.

These included shingles that were too thin and

consequently had a tendency to curl, also flat grain shingles, and those containing sapwood

and knots. A great many of the roofs between

[9]
-7 /

'

Figures 20 to 25.—TF^ooci shingles.

n^ii/iwl'hntt, nfl"^; irc^iclT/K*^

southern sections respectively, of a roof after approximately 50 years of exposure in Bismarcli, N. Dale.; 22, loose nails wheie butts of shingles had been nailed; 23, thin (6/2 shingles exposed 11 years in Sioux FaDs, S. Dak.; 24 and 25. southern and northern sections respectively, of a roof after approximately 30 years of exposure in Omaha Nebr

soumerii aim noitnern sections.

10 and 20 years old that were examined in this

survey were of inferior quality.

Although inferior shingles may be obtained

today, it is by choice rather than from necessity.

The Commercial Standard CS31-38 for wood

shingles, adopted for red cedar shingles in 1931,

revised to include California redwood and

tidewater red cypress shingles in 1933; and

10

i
reaflirmed in 1935 and 1938, provides a minimum specification for the highest commercial

grade of sawn wood shingles of the above

species. This is known as No. 1 Grade in American Lumber Standards. It covers length

width, thiclvness, grain, characteristics, color,

packing, and the grading tolerances for these

requirements.

Commercial standard shingles are required

to be 100 percent heartwood and strictly

vertical, or edge-grained . The minimum length

is 16 inches, with other standard lengths of 18

and 24 inches. Minimum width for shingles

less than 24 inches long is 3 inches ; for those 24

inches and longer the minimum width is 4 inches.

The thiclaiess of shingles is determined at the butt ends, and is expressed as the number

of pieces necessary to constitute a defhiite unit

of thiclaiess, as "4/2" indicates that four butts measure 2 inches, or "5/2%" that five butts measure 2% inches. The minimiim thickness of 16-inch shingles is 5/2.

Figures 20 and 21 represent the northern and

southern exposures, respectively, of a wood

shingle roof in Bismarck, N. Dak., reported to be 50 years old. These were heavy, red cedai' shingles of good grade, which showed considerable weathering, particularly on the southern

exposure, but which were in a satisfactory condition when examined. A number of broken

shingles had been replaced recently on the southern exposure, and on the northern exposure

practically all of the butts had been nailed

down. This practice is not generally recom- mended because of the tendency of the exposed

nails to become loose, as illustrated in figure 22. These shingles were not weathered badly, after

15 years of exposure in Omaha, Nebr., but

they had shown some tendency to warp and

had been nailed through the butts. Aftei' further exposure, a number of these nails

became loose and each nail hole became a potential leak. Figure 23 is a roof of wood shingles after about 11 years of exposure in Sioux Falls, S. Dak. These were shingles of good quality,

except that the butts were too thin. The

shingles shown in figure 23 were about 6/2, six butts in 2 inches.

Figure 24 shows the southern exposure of a wood -shingle roof after approximately 30 years

of service in Bismarck, N. Dak. The northern

exposure of this roof, on which the shingles

showed less curling, and with fewer of them

cracked, is illustrated in figure 25. These

shingles also show plainly the erosion caused by

long exposure.

Figure 26 illustrates a roof of thin, poorly

gi'aded shingles after 18 years of exposure in Milwaukee, Wis. This roof was on 1 of 20

dwellings that had been erected at the same

time, and when examined, all but 2 of them had

been reroofed.

That the thiclaiess of shingles is an important

factor is further illustrated by figure 27, in which the shingles were almost 1 inch thick at the butts. They had been exposed for 15

years in Omaha, Nebr., yet the roof had the

appearance of a new one. Shingles that re- main flat after long exposure present a lesser fire hazard than those that are warped and curled.

Figure 28 is an excellent example of poorly

graded shingles, with edge and flat grain

shingles mixed. One shingle in the second

course shows a loiot at the end of the exposed

butt.

Figure 29 is representative of several hundred roofs 14 years old in Cincinnati, Ohio.

These were first-grade shingles and, generally,

have withstood weathering very well. Figure

30 is a close-up of some of these shingles showing that they are all edge grain.

Figure 31 shows wood shingles laid to simulate the appearance of a thatched roof. By

this method the shingles ai'e laid with very small

exposure so that they usually give excellent

service. The roof illustrated was 17 years old

(c) Cement-Asbestos Shingles

Cement-asbestos shingles have been used

throughout this territory for a number of years, but in only one city, Omaha, Nebr., do cementasbestos roofs constitute a considerable per- centage of the total number of roofs. Their

use has been mainly on dwellings in the medium

price classes, although at present newer types

of cement-asbestos shingles, laid by the American method, are being used on more expensive

dwellings. Shingles laid by the Dutch lap and

[11]
Figures 26 to 31.—Wood shingles.

Figure 26, thin, poorly graded shingles, exposed 18 years in Milwaukee, Wis.; 27, heavy shingles e.xposed 15 j'ears in Omaha, Nebr.; 28, poorly graded

shingles; 29 and 30, first-grade shingles expo.^ed 14 years in Cincinnati, Ohio; 31, shingles laid to simulate a thatched roof.

hexagonal methods are being used on dwellings

in the lower price classes. The oldest cement-asbestos shingles, observed

in several locations, make a diamond pattern

when laid. Several roofs of these shingles that

had been exposed for approximately 30 years

appeared to be in good condition, and were

reported to have given no trouble except when

some of the shingles were damaged by being

walked upon.

[12]
The effect of weathering of cement-asbestos

I shmgles observed in this survey was similar to

j that seen in the previous surveys; that is, on

long" exposure the surface became I'oughened

somewhat, and the asbestos fibers were plainly

visible. It has not been possible to establish

differences in the rates of weathering of cementI asbestos shingles in different localities.

1 Figure 32 is a close-up of hexagonal pattern

' shingles after 15 years of exposure in PittsI burgh. Pa. These shingles showed considerable

j surface weathering, no doubt accentuated by

the industrial atmosphere, but they were not

badly discolored and appeared in good condition. The dark sections of these shingles were made by embedding mineral granules in the

surface. Figure 33 illustrates the oldest cementasbestos shingles that were observed. They

showed considerable surface weathering and

discoloration after 30 years service in Toledo,

Ohio. Several cities that had suffered severe

hail storms during the past years were visited

in this survey. Cement-asbestos shingles were

reported in each case to have been damaged

very little if at all. Figure 34 illustrates cement-asbestos shingles laid by the American method after 10

years of exposure in Alilwaukee, Wis. The

corners of these shingles had been broken purposely when they were laid. Figure 35 shows cement-asbestos shingles laid

by the Dutch-lap and hexagonal methods on a group of new dwellmgs in Omaha, Nebr.

id) Slate

In the cities included in this survey, excepting

Pittsburgh, Pa., and Cincinnati, Ohio, slate roofs were observed only on dwellings in the

higher price classes. This is undoubtedly due

to the high transportation costs from the slate- producing areas in the East.

Slate that has been used has been mainly

from the East Pennsylvania quarries m Lehigh

and Northampton coimties, and from quarries in Vermont where colored slates are produced.

The weathering of slates from the different

producing areas has been discussed in BMS29.

The types of weathering observed in the present area were the same as those described in the

report on the Northeastern States, and it was

not possible to distinguish differences in the

degree of weathering of slate in the two

areas. The condition of slate roofs in Pittsburgh,

Pa., can be taken as representative of this material in severe industrial atmospheres.

Slate roofs which have been widely used in this city since about 1894, probably total about 75

percent of all dwelling roofs at present. That

fact, and the fact that slate is being used in about the same pi-oportion today indicates thai,

it is a satisfactory material in industrial locations. Because of the accumulation of soot and dirt on most slate roofs in Pittsbiirgh very little could be learned of the weathering characteristics of the different kinds of slate. Figure

36, which is typical of many slate I'oofs more

than 40 years old, shows some flaking of the

surface layer, leaving white or gray patches

exposed. These slates were from the LehighNorthampton region.

Figure 37 shows typical fading of eastern Pennsylvania slates after exposure of 40 years

in Omaha, Nebr.

Figure 38 is a roof of colored slate from

Vermont, also in Omaha, that was 40 to 45

years old. The slates on this roof were in

excellent condition, but there had been some

failure of the nails that were used to fasten

them.

Variations in the conventional method of laying slate were observed in Cincinnati, Ohio,

where they have been used to a considerable

extent. Bj these methods the amount of slate per unit area of roof is reduced by substituting

asphalt-prepared roofing for a part of the slate. Courses of asphalt-prepared roofing of the same width as the slate, or wider, are laid alter- nately with the courses of slate and the slates in one course are lapped at about 3 inches over

those in the next course below. This method of

laying is illustrated by the edge of the roof

shown in figure 39. Figure 40 shows a roof

laid by one of these methods, after 5 years of

service. The owner of this roof shown in figure 40 reported that it had been entirely

satisfactory.

[13]
I

Figures 32 to 37.

Cernent-ashcstos siiingles and slate.

Figures 32 to 35, inclusive, cement-asbestos shingles; 32, after 15 years in Pittsburgli, Pa.; 33, after 30 years in Toledo, Ohio; 34, after 10 years in Milwaukee, Wis.; 35, new dwellings in Omaha, Nebr., roofed with cement-asbestos shingles; 36 and 37, eastern Pennsylvania slate, 36, after more than

40 years in Pittsburgh, Pa.; 37, after 40 years in Omaha, Nebr.

(e) Built-up Roofing expected that a later publication will discuss the

weathering qualities of built-up roofs. Material

As in the previous surveys, no detailed study for this report is being obtained from inspections

of built-up roofs was made in this survey. It is by competent engineers of roofs on Govern-

[14]
FiGUBES 38 to 43.

Slate and tile.

Figures 38 to 40 slate; 38. Vermont slate exposed 40-45 vears in Omaha, Nebr.; 39 and 40, slate roofs in which asphalt-prepared roofing is substituted

lor part of the slate; 41, shinele-tile roof exposed 35 years in Omaha, Nebr.; 42, glazed tUe 16 years old in Indianapolis, Ind.; 43, cement-tUe roof in sioux

Falls, S. Dak.

nient-owned buildings throughout the country.

(J) Tile

Tile roofs in the area covered by this survey

were observed mainly on the more expensive

dwellings. All types of tile roofs were observed, but shingle tiles apparently predominated on the more recent dwellings. Of par-

[15]
Figures 44 to 4'J. —Mi lal roof, flasJihigs, and vnlleys

Figure 44, heavily galvanized roofing exposed 46 years in Southern Illinois; 45, absence of chimney flashing on wood-shingle roof; 46 and 47, respectively, low, step flashing and high metal flashing; 48, valley made by interlacing asphalt shingles; 49, divided metal valley.

ticular interest were the highly glazed tiles that

do not change in appearance over long periods

of exposure.

Considerable damage to cement tile roofs was

[

reported in the locations subject to severe

hailstorms.

Figure 41 illustrates a shingle-tile roof after 35 years of exposure in Omaha, Nebr. These

]
tiles were 12 inches long and were exposed 5

inches. The edge of the dormer roof shows how

they were applied. Figure 42 shows a roof of

glazed tile 16 years old, in Indianapolis, Ind.

This roof had the appearance of a new one. Figure 43 illustrates a cement tile roof in Sioux Falls, S. Dak. The area of this roof was

16 squares. The owner reported that it had

been necessary to replace 112 tiles in this roof

after a severe hailstorm several years ago.

{g) Metal

As had been stated in reports of the previous

surveys, it is practically impossible to state

definitely the life, in years, of various metallic

roofing materials. Theii' durability is determined largely by the character of the material,

character of the coating, if a coated sheet is used, conditions of exposure, and degree of care and maintenance.*

The evidence obtained to date in this work

indicates that suitably selected metallic roofing

which is properly cared for, will render satis- factory service under normal conditions of exposure. Figure 44, of a heavily galvanized

corrugated roof on a farm building in southern

Illinois after 46 years of exposure, illustrates the

long service that can be expected from galvanized metal with a heavy coating of zinc.

3. Flashings, Valleys, Gutters, and DoavnSPOUTS

These items, invariably present on most roofs, are made principally from sheet metal. Sheet

copper, galvanized iron or steel, roofing terne,

and asphalt-roll roofing were found to be used.

The present-day trend to the use of pitched

roofs in residential construction, with a minimum of slopes and components, has simplified

greatly the prevention of the leaks that were

usually associated with the older type of roofs. In general, it was observed that while care is usually exercised in the design and construction

of these accessories, subsequent periodic maintenance is not always carried out. This often

leads to premature failure, particularly where

ferrous sheet materials are employed.

* Building Materials and Structures Report BMS 49, Metallic Roofing

for Low-Cost House Construction. Price 100. See cover page IV.

(a) Flashings

Copper, terne, and galvanized iron or steel are wi(k4y used for chimney and vent Hashings.

A few cases were observed of the use of roll roofing for chimney flashings; also where no

flashings were used on either wood-shingle roofs

(fig. 45) or asphalt-shingle roofs. This practice

affords, generally, only temporary protection

from leakage, particularly if plastic cement is utilized for sealing the shingles or roll roofing

to the chimney.

On some of the older dwellings that are located close to industrial plants corrosion

troubles have been encountered with metalUc

flashings, but on many of the newer residential

buildings these difficulties have been minimized

by locating the newer residential sections at greater distances from manufacturing areas, and by adequate painting.

The height of metallic chimney flashings

appears to vary considerably between various

sections, from the low-stepped type (fig. 46) to the high type (fig. 47).

(6) Valleys

Copper, galvanized metal, terne, and roll roofing are used most frequently for valley

flashing. Asphalt shingles, are frequently laced

or overlapped to produce closed valleys, particularly on some of the newer types of residential

construction, figures 46 and 48. Open valleys

are usually narrow and occasionally are divided

if metal is used for their construction (fig. 49).

(c) Gutters and Downspouts

These accessories are widely used on houses

in the North-Central Section. Most gutters

and downspouts are constructed of either

copper or galvanized metal, the former material

being confined usually to houses in the higherpriced classes. Pole and hidden gutters are found on a few of the older houses but are seldom used on new ones. Observations indicated unsatisfactory service

from metallic gutters and downspouts in some

sections, particularly those close to large industrial areas where the atmosphere is contaminated with industrial gases which cause rapid

deterioration of the metal. This was true in

[17]
the Pittsburgh, Pa., area where metal gutters

are being largely replaced with fir.

V. EXTENT OF USE OF THE VARIOUS

ROOFING MATERIALS IN URBAN

CENTERS IN THE NORTH CENTRAL

STATES

1. Factors Which Affect the Choice of

Roofing Materials Generally

This subject is discussed in considerable

detail in BMS6 and BMS29 so it will be

treated only briefly here. Initial cost, cost of

maintenance, fire resistance, and appearance

are factors that influence the choice of roofing

materials generally. Availability, insurance

rates, and city regulations also govern the

extent of use of the various materials to a considerable degree. While most materials

may be used in any location if given proper care, some materials are much better suited than

others for particular weather conditions, so that climate is one of the more important

considerations.

2. Distribution of Roofing Materials in

THE Cities Included in This Survey

Data obtained by the questionnaire method,

reported in BMS57, indicate that the Mississippi River divides the country rouglily into

two sections as regards the present distribution

of roofing materials, with wood shingles pre- dominating west of the Mississippi River, and

asphalt shingles east of it. At the time this survey was made, asphalt shingles predominated in most of the cities visited, both on new

and old dwellings, with a considerably quantity

of asphalt-prepared roll roofings used mainly

for reroofing over wood and asphalt shingles.

Wood shingles were formerly used more

extensively than any other material in all of the

cities visited, with the probable exception of

Pittsburgh, Pa., until about 20 years ago, or when asphalt shingles began to have general

use. Wood-shingle roofs still predominate in Bismarck, N. Dak., Sioux Falls, S. Dak., and

Kansas City, Mo.

The rather widespread adoption by most

cities of regulations prohibiting the use of wood

shingles in congested areas, or requiring that

existing wood-shingle roofs be covered with a

fire-resisting material, contributed greatly to the use of asphalt shingles and asphalt-prepared

roll roofings. In the older sections of most of these cities there are thousands of old woodshingle roofs covered with these materials.

In some cases, the first asphalt roof has been

re-covered with another asphalt roof. 1 Except in the cities listed above, and in Omaha, Nebr., asphalt shingles are being used on most new dwellings in the lower price classes. This does not necessarily mean only in the

lowest price classes, because in some cities, \ particularly in Chicago, 111., whole subdivisions were observed where asphalt shingles were

being used on dwellings selHng for $10,000 to $11,000.

Omaha, Nebr., is outstanding for its wide

use of cement-asbestos shingles on new dwellings selling for $6,000 and more. Cementasbestos shingles have been very popular in \ Omaha for a number of years.

j In comparison with other materials, metal

roofing finds little use in any of the cities cov- ered in this survey. Some relatively old terne

'

roofs were found in the older sections of most

of the cities visited. An occasional roof of |i terne, copper, metal shingles or metal tile was

found scattered throughout the older resi- dential sections. Small districts were occasionally found within a given district where

relatively flat roofs, either built-up or terne are ! used. 1

VI. ROOFING COSTS IN URBAN CENTERS IN THE NORTH CENTRAL

STATES

The prices, as of the approximate date of this survey including cost of application, per square

(100 square feet of roof surface) for each of the j materials listed in table 4 were furnished by ; repi'esentatives of the Home Owners' Loan i Corporation in Pittsburgh, Pa. ; Cincinnati and

Toledo, Ohio ; Indianapolis, Ind. ; Grand Rapids,

Mich; Chicago, 111.; St. Paul, Minn.; Sioux

Falls, S. Dak. ; Omaha, Nebr. ; and Kansas

City, Moberly, and St. Louis, Mo. The range

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

maximum costs were distributed among the

[18]
different cities and were not confined to a particular one. The average cost shown is the

average for all of the cities.

Table 4.

Costs of roofing materials, including application per square, on a simple pitched roof with no

valleys, but including chimney flashings

[Data supplied by the Home Owners' Loan Corporation 'J

Materials

Asphalt shingles: Giant individual, 12 by 16 in., American method

Standard individual, 9 by 12% in., American method

Four-tab square butt strip 12}'2 by

36 in Three-tab square butt strip 12 by

36 in. overlay Two-tab hexagonal strip 11}^ by 36

in Individual re-cover, Dutch lap

Individual re-cover, hexagonal

Asphalt roll roofing: Mineral-surfaced- Smooth-surfaced.

Cement-asbestos shingles (gray color only)

American method

Hexagonal method

Dutch-lap method

Slate_-. Wood shingles. Metal roofing: Shingles (galvanized) Five V-crirap 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

Lb.

325

255

266

211

167

125 to 140

125 to 140

Cost per square

Mini- mum

Maxi- mum

Average

$9. 50 .$16. 00 $12. 25

8. 50 13. 50 10. 90

8.25 12. 50 10. 20

7. 75 12. 75 9. 35

6. 50

5. 25

5. 25

10.00

9. 50

9. 50

7. 70

7. 25

7. 30

3.90

3.26

5. 25

4. 70

4. 65 4.00

18. 00

11. 00

11.50

31.50

17. 75

17. 75

22. 25 14.85

15. 40

20. 00

6. 85

30. 00

12. 50

24. 55

10. 35

10. 00

6. 75

30. 00

22. 00

16. 55 11.75

16. 00 45.00 22. 05

16. 00 42. 50 24.70

19. 00

18. 00

43. 00

31.50

33. 30

25. 80

6. 50 14.00 10. 80

7. 25 14. 00 10. 75

1 August-September 1941.

VII. SUMMARY

1. Distribution

The initial cost and the cost of maintenance,

including fire insurance, availability, and appearance largely govern the choice of roofing

materials on dwellings in the lower price classes. The more expensive materials, which are usually

heavier and require a stronger supporting structure, are normally found on the dwellings in the

higher price classes. Roofs of asphalt shingles, wood shingles and

sheet metal are found on approximately 76

percent of the rural dwellings along the routes

traveled in the three surveys to date. Sheetmetal roofs predominate on low-cost rural dwellings in the Southeastern States; asphalt

shingles on dwellings of the same class in the

Northeastern States; and wood shingles in the

North Central States. The use of wood shingles increases as one travels toward the northwest. They are used almost exclusively on

both the rural and urban dwellings in North

Dakota.

Asphalt-prepared roll roofings have been used

extensively for reroofing throughout most of the

North Central States. Large quantities of

these roll roofings have one edge cut to form

a regular pattern. These roofings are apparently more popular than the single-coverage

shingles generally employed for reroofing over wood shingles in the Southeastern States, and

to a smaller extent in the Northeastern States. Fewer metal roofs were observed on dwellings

in the North Central States than in the Southeastern or Northeastern States. Some very

old tin and galvanized-iron roofs remain.

A comparatively large number of slate roofs,

many of them very old, were found throughout

Pennsylvania and Ohio in both the rural and

urban sections.

2. Weathering

After weathering, asphalt shingles and roll roofings in the North Central States exliibit the same characteristic features as in the

Northeastern and Southeastern States. The

oldest asphalt-shingle roofs that were examined

were 29 years old, of individual shingles, in

Grand Rapids and Zeeland, Mich. In this territory were observed many asphalt-shingle

roofs older than 20 years, also many roll-roofing

roofs up to 20 years old. Weathering proceeds more rapidly in the

southern sections of the North Central States. In cities such as Kansas City and St. Louis,

Mo.; Indianapolis, Ind.; and Cincinnati, Ohio

most of these roofs are replaced or re-covered

within 20 years. Wood-shingle roofs in fair condition after an

exposure of 25 to 50 years were observed,

although some were observed that were in poor

condition after less than 20 years of exposure.

Difference in the grade or quality of the shingles

rather than in the exposure conditions is the

[19]
controlling factor in weathering. Thin shingles,

and those that are poorly graded, with knots

and sapwood in the sections that are exposed,

usually cm-1 and crack within a comparatively

short time.

Wood shingles less than 10 years old, or considerably older if they are of fu'st quahty, are

Httle affected by hail storms and strong winds.

Slate roofs 50 or more years old are not un- common. Slates that are classed as nonfading

are usually only slightly changed on long ex- posure. Many old slate roofs fail because of

failure of the nails.

VIII. SELECTED REFERENCES^

1. Asphalt Shingles and Roll Roofing:

(a) Herbert Abraham, Asphalts and Allied Sub- - stances, 4th ed. (D. Van Nostrand Co.,

Inc., New York, N. Y., 1937.)

(b) 0. G. Stricter, A study of the weathering

quality of roofing felts made from various

fibers. J. Research NBS 16, .511 (1936)

RP888. Out of print.

(c) O. G. Stricter, Weathering tests on filled coating

asphalts. J. Research NBS 30, 159 (1938)

RP1073. 10^.

(d) Hubert R. Snoke, Asphalt-Prepared Roll Roofings and Shingles. NBS Building Materials and Structures Report BMS70

(1941). 15^

(e) Hubert R. Snoke and Braxton E. Gallup.

Accelerated weathering tests of mineralsurfaces asphalt shingles. J. Research

NBS 18, 669 (1937) RP1002. 10^.

(f) Roofing and Shingles; Asphalt - Prepared,

Mineral-Surfaced Federal Specification,

SS-R-521 (1933). 5i

2. Wood Shingles:

(a) J. A. Ferguson, Comparative Durability of Shingles and Shingle Nails, Bulletin 353,

Pennsylvania Agricultural Experiment Station, State College, Pa. (1938).

(b) Wood Shingles (Red Cedar, Tidewater Red

Cypress, California Redwood), NBS Commercial Standard CS31-38 (1938). 5^

(c) Red Cedar Shingle Bureau, Handbook of Red

Cedar Shingles, Seattle, Wash. (1940).

3. Cement-Asbestos Shingles:

(a) Shingles; Roofing, Cement-Asbestos, Federal

Specification SS-S-291 (1935). 5^

5 Many public, college, and university libraries throughout the country have the publications of the Bureau and possibly also publications from other branches of the Government. Where prices are given in this

list, the publications may be purchased from the Superintendent of Documents, United States Government Printing Office, Washington, D. C. Postage stamps should not be sent.

4. Slate:

(a) D. W. Kessler and W. H. Sligh, Physical properties and weathering characteristics of slate, BSJ, Research 9, 377 (1932) RP477. lOji (b) T. Nelson Dale and Others, Slate in the United States, Bulletin 586, United States Geological Survey (1914). Out of print.

(c) Oliver Bowles, The Technology of Slate, Bulletin 218, Bureau of Mines, United

States Department of the Interior (1922)-.

20fS (d) Charles H. Behre, Jr., Slate in Pennsylvania,

Bulletin M16, Topographic and Geologic

Survey, Department of Internal Affairs, Harrisburg, Pa. (1933).

(e) Roofing Slate, NBS Simplified Practice Rec- ommendation R14-28 (1928). ^

(f) Slate; Roofing, Federal Specification SS-S-451

(1932). 5?i

5. Tile:

(a) WoLSEY Garnet Worcester, The Manufacture

of Tiles, fourth series. Bulletin 11, Geological Survey of Ohio, Columbus, Ohio (1910).

(b) T. A. Aekworth, Manufacture of Roofing

Tile. Maclaren and Sons, Ltd., London,

England.

6. Metal:

(a) National Association of Sheet Metal Contractors, Standard Methods of Sheet Metal

Practices, Pittsburgh, Pa. (1938).

(b) Burns and Schuh, Protective Coatings for Metals, American Chemical Society Monograph Series 79 (Reinhold Publishing

Corp., New York, N. Y., 1939).

(c) Leo J. Waldron, Metallic Roofing for LowCost House Construction. NBS Building

Materials and Structures Report BMS49

(1940). 10^5 (d) Terne-Plate (Roofing-Tin) , Federal Specifica- tion QQ-T-201 (1930). 5^

(e) Roofing Ternes, NBS Simplified Practice Recommendation R30-37 (1937). 5(4

(f) Copper and Brass Research Association, Sheet Copper Handbook, New York, N. Y.

(1937).

(g) American Zinc Institute, Inc., Zinc Workers

Manual, New York, N. Y. (1929).

7. General, Including Built-Lip Roofing:

(a) James McCawley, Roofing: Estimating—Applying—Repairing (175 Fifth Avenue, New

York, N. Y., 1938).

(b) Ernest G. Blake, Roof Coverings (D. Van

Nostrand Co., Inc., 1925).

(c) Joseph Ross, Waterproofing Engineering

(John Wiley and Sons, Inc., New York,

N. Y., 1919).

(d) Hubert W. Snoke and Leo J. Waldron, Survey

of Roofing Materials in the Southeastern

States, NBS Building Materials and

Structures Report BMS5 (1936). 15ji.

[20]
(e) Hubert R. Snoke and Leo J. Waldron, Survey

of Roofing Materials in the Northeastern

States, NBS Building Materials and Structures Report BMS29 (1939). 10(6

(f) Leo J. Waldron and Hubert R. Snoke, Roofing

in the United States—results of a Questionnaire. NBS Building Materials and

Structures Report BMS57 (1940). 10^

(g) A. D. Edgar and T. A. H. Miller, Roof Coverings for Farm Buildings and Their Repair, Farmers' Bulletin 1751, United States Department of Agriculture (1935). 5^

(h) Roofing, Siding, and Sheet Metal Work;

Dampproofing and Membrane Waterproofing, Navy Department Specification No. 7Yg (1934).

(i) LLst of Inspected Fire Protection Appliances,

published annually by Undervvriters' Laboratories, Inc., Chicago, 111.

(j) Asphalt; (for) Built-Up Roofing, Waterproofing, and Dampproofing, Federal Specification SS-A-666 (1933). ^

(k) Pitch; Coal- Tar (for) Mineral-Surfaced Built- Up Roofing, Waterproofing, and Dampproofing, Federal SpecificatioTi R-P-381

(1933). bji (1) Felt; Asphalt-Saturated Felt (for) Flashings,

Roofing, and Waterproofing, Federal Specification HH-F-191 (1933). 5(6 (m) Felt; Coal-Tar-Saturated Felt (for) Roofing

and Waterproofing, Federal Specification

HH-F-201 (1933). H

Washington, April 11, 1941.

o

[21]

BUILDING MATERIALS AND STRUCTURES REPORTS

On request, the Superintendent of Documents, U. S. Government Printing OfRce, Washington, D. C, will place your name on a specia,l mailing list to receive notices of new reports in this

series as soon as they are issued. There will be no charge for receiving such notices. An alternative method is to deposit with the Superintendent of Documents the sum of $5,

with the request that the reports be sent to you as soon as issued, and that the cost thereof be

charged against your deposit. This will provide for t.he mailing of the publications without

delay. You will be notified when the amount of your deposit has become exhausted.

If 100 copies or more of any paper are ordered at one time, a discount of 25 percent is allowed. Send all orders and remittances to the Superintendent of Documents, U. S. Government Printing

Office, Washington, D. C.

The following publications in this series are available by purchase from the Superintendent of Documents at the prices indicated:

BMSl Research on Building Materials and Structures for Use in Low-Cost Housing. . lOjS BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base . 10^ BMS4 Accelerated Aging of Fiber Building Boards : 10^ BMS5 Structural Properties of Six Masonry Wall Constructions 15(S BMS6 Survey of Roofing Materials in the Southeastern States 15^ BMS7 Water Permeability of Masonry Walls c^., 10^ BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10^ BMS9 Structural Properties of the Insulated Steel Construction' Co. 's "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs 10^ BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co , 10^ BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 10^ BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 15(t 3MS13 Properties of Some Fiber Building Boards of Current Manufacture 10^ BMS14 Indentation and Recovery of Low-Cost Floor Coverings 10^ ,BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored by

the Wheeling Corrugating Co 10^ BMS16 Structural Properties of a "Tilecrete" Floor Construction Sponsored by Tilecrete

Floors, Inc _ 100 BMS17 Sound Insulation of Wall and Floor Constructions . 10^ BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation 10^ BMS19 Preparation and Revision of Building Codes 15^ BMS20 Structural Properties of "Twachtman" Constructions for Walls and Floors Sponsored by

Connecticut Pre-Cast Buildings Corporation 100 BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association 100 BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 100 BMS23 Structural Properties of a Brick Cayity-Wall Construction Sponsored by the Brick

Manufacturers Association of New York, Inc ; 100 BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile CavityWall Construction Sponsored by the Structural Clay Products Institute., 100 BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions,

Floors, and Roofs 150 BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction

Sponsored by the Nelson Cement Stone Co., Inc 100 BMS27 Structural Properties of "Bender Steel Home" Wall Construction Sponsored by The

Bender Body Co 100 BMS28 Backflow Prevention in Over-Rim Water Supplies 100

BMS29 Survey of Roofing Materials in the Northeastern States 100

[List continued on cover page iv]
BUILDING MATERIALS AND STRUCTURES REPORTS

[Continued from cover page in]

BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas

Fir Plywood Association 10^ BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co 15^ BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block Wall Construction Sponsored by the National Concrete Masonry Association. 10^ BMS33 Plastic Calking Materials lOi BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 lOfS BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging 10^ BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions

with "Red Stripe" Lath Sponsored by the Western Paper and Manufacturing Co 10^ BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors Sponsored by Palisade Homes 10^ BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co , 10^ BMS39 Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co 10^ BMS40 Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored

by Knap America Inc 10^ BMS41 Efifect of Heating and Cooling on the Permeability of Masonry Walls lOfi BMS42 Structural Properties of Wood-Frame Wall and Partition Constructions with "Celotex"

Insulating Boards Sponsored by the Celotex Corporation 10^ BMS43 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 lOjS BMS44 Surface Treatment of Steel Prior to Painting 10^ BMS45 Air Infiltration Through Windows lOf BMS46 Structural Properties of "Scot-Bilt" Prefabricated Sheet-Steel Constructions for Walls,

Floors, and Roofs Sponsored by The Globe-Wernicke Co 10^ BMS47 Structural Properties of Prefabricated Wood-Frame Constructions for Walls, Partitions,

and Floors Sponsored by American Houses, Inc 10^ BMS48 Structural Properties of "Precision-Built" Frame Wall and Partition Constructions

Sponsored by the Homasote Co 10^ BMS49 Metallic Roofing for Low-Cost House Construction 10(4 BMS50 Stability of Fiber Building Boards as Determined by Accelerated Aging lOfi BMS51 Structural Properties of "Tilecrete Type A" Floor Construction Sponsored by the Tile- crete Corporation lOjS BMS52 Efifect of Ceiling Insulation Upon Summer Cbmfort lO^i BMS53 Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored by the Munlock Engineering Co 10f5 BMS54 Effect of Soot on the Rating of an Oil-Fired Heating Boiler 10^ BMS55 Effects of Wetting and Drying on the Permeability of Masonry Walls 10^ BMS56 A Survey of Humidities in Residences 10^ BMS57 Roofing in the United States—Results of a Questionnaire lOfi BMS58 Strength of Soft-Soldered Joints in Copper Tubing 10^ BMS59 Properties of Adhesives for Floor Coverings 10^ BMS60 Strength, Absorption, and Resistance to Laboratory Freezing and Thawing of Building

Bricks Produced in the United States 15<S BMS61 Structural Properties of Two Nonreinforced Monolithic Concrete Wall Constructions 10^ BMS62 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by the Portland Cement Association lO^i BMS63 Moisture Condensation in Building Walls 10^ BMS64 Solar Heating of Various Surfaces 10^ BMS65 Methods of Estimating Loads in Plumbing Svstems 10^ BMS66 Plumbing Manual 20^ BMS67 Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by Herman A. Mugler 15^ BMS68 Performance Test of Floor Coverings for Use in Low-Cost Housing. Part 3 15^ BMS69 Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 10^ BMS70 Asphalt-Prepared Roll Roofings and Shingles 15^ BMS71 Fire Tests of Wood- and Metal-Framed Partitions 20^ BMS72 "Precision-Built, Jr." Prefabricated Wood-Frame Wall Construction Sponsored by the Homasote Co lOfi BMS73 Indentation Characteristics of Floor Coverings 10^ BMS74 Structural and Heat-Transfer Properties of "U. S. S. Panelbilt" Prefabricated Sheet-Steel Constructions for Walls, Partitions, and Roofs Sponsored by the Tennessee Coal, Iron and Railroad Co 15^ BMS75 Survey of Roofing Materials in the North Central States 15^