The program of research on building materials and structures, carried on by the

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

housing construction and finance, which is cooperating in the investigations through a subcommittee of principal technical assistants.

CENTRAL HOUSING COMMITTEE

SUBCOMMITTEE OF TECHNICAL RESEARCH

Waltek Jtjnge, Chairman. A. C. Shiee, Vice Chairman.

Federal Housing Administration. United States Housing Authority.

Sterling R. March, Secretary.

Albert G. Bear, George E. Knox,

Veterans' Administration. Yards and Docks (Navy).

Pierre Blouke, Vincent B. Phelan,

Federal Home Loan Bank Board. National Bureau of Standards (ComCarroll W. Chamberlain, merce).

Procurement Division (Treasury). Edward A. Poynton,

Joseph M DallaValle, ^^^^ j^^.^^ ^^^.^^ (Interior).

Public Health Service (lederal becu- ^ . »„ . s George W. Trayer,

nty Agency).

T TTk r^.r.^. Forest Service (Agriculture). John Donovan, ^ ^ ^ Farm Security Administration (Agri- Elsmere J. Walters,

culture). Construction Division (War).

CHAIRMEN OF SECTIONS

Specifications Materials Maintenance

Carroll W. Chamberlain Elsmere J. Walters John H. Schaefer

Mechanical Equipment Methods and Practices

Robert K. Thulman

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 Silicate 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 United States Department of Agriculture

is cooperating with both committees on investigations of wood constructions.

[For list of BMS publications and how to purchase, see cover page III.]
UNITED STATES DEPARTMENT OF COMMERCE • Harry E. Hopkins, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director BUILDING MATERIALS

and STRUCTURES

REPORT BMS35

Stability of Sheathing Papers as Determined

by Accelerated Aging

by

SAMUEL G. WEISSBERG, DANIEL A. JESSUP

and CHARLES O. WEBER

ISSUED DECEMBER 22, 1939

The National Bureau ot Standards is a fact-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

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

1939

10 CENTS
Foreword

Sheathing paper constitutes a relatively small part of the total cost of a house.

However, the importance of the paper as a component part of the structure may be

many times greater than its cost would indicate. It is used as a barrier against the

infiltration of water and air from the outside, and agamst loss of moisture vapor from

within. Papers that will perform these functions satisfactorily while new are readily

available, but heretofore no data were available on the stability of these products.

This report presents the results of tests to determine the relative lasting qualities of some

of the more common types of commercial sheathing papers.

Lyman J. Briggs, Director.

[11]
Stability of Sheathing Papers as Determined by

Accelerated Aging

by

SAMUEL G. WEISSBERG, DANIEL A. JESSUP, and CHARLES G. WEBER

CONTENTS

Foreword

I. Introduction

II. Description of samples

L Laminated paper products.

Page

II

12

2

2. Single-ply, asphalt-treated 2

3. Metal-foil laminated products 2

4. Rosiii-sized paper 2

Page

III. Determination of stability by accelerated aging 2

\. Permeability to air, water, and water vapor 4

2. Strength 5

3. Shrinkage 6 IV. Summary and conclusions 0

ABSTRACT

The more familiar types of sheathing papers were

tested to obtain authoritative information on how well they can be expected to retain their desirable qualities

in service. Accelerated aging was used, because to obtain comparable data from natural aging would re- quire much more time. The aging treatment included

cycles of wetting, freezing, drying, and baking; and the

effects of the treatment were observed by comparison of the properties before and after aging. Important properties of this class of papers are resistance to the passage

of air, water, arrd water vapor; hence, the judgment of

stability was based largely on the degree of retention of those attributes. In general, the papers lined with

metal foils were least affected by aging. The asphalt- treated papers differed widely. The single-ply papers as a class had lower initial resistance to water and moisture vapor than the laminated papers but retained the resis- tance somewhat better than the latter, although one

of the duplex papers received a very high rating. Rosinsized papers had unsatisfactory aging properties.

I. INTRODUCTION

Sheathing papers have an important place in most house building. Originally used in frame

construction as a protection against the infiltra- tion of air and the passage of water through

walls, they now have additional protective functions. They serve as barriers against the infil- tration of water and water vapor in practically

all types of construction, including frame,

stucco, and brick veneer. Also, with the advent

of air conditioning, and with the increasing use

of fill insulation, sheathing paper has become

very important as a seal against the passage of moisture vapor from within the structure,

which may result in sufficient condensation

within the walls dixring the vnnter months to cause serious damage to the structure. Studies of some of the properties of sheathing

papers have been made by Carson,' and a Federal specification ^ contains well-established

values for strength and water resistance. More

recently, studies of the problem of condensation

of moisture within walls have included tests of the relative efficiency of various sheathing

papers as moisture seals. Results of these

tests have been published by investigators ^ at the Forest Products Laboratory at Madison,

Wis.

From the information already available, it appears that sheathing papers are made to meet

all ordinary requirements for strength and re- sistance to permeation by water, water vapor,

and air. It is, therefore, not difficult to obtain

a paper which will perform a specific function

within a wall initially. Heretofore there has

been no information available relative to the

stability of such papers. It was the purpose of

this investigation to obtain data on how long

the papers can be expected to perform the

functions for which they are selected. The most

satisfactory method of predicting their service

life would be to base an estimate on field observations after years of service. However, as such data are not available, and because of the

' BS J. Research 3, 75 (1929) RP85.

a Federal Specification UU-P-536, Paper; Sheathing, Waterproof.

3 Heinig, Teesdale, and Curran, Comparative resistance to vapor trans- mission. Presented at 1939 Annual Meeting, Tech. Assn. Pulp & Paper

Ind., N. Y.

185263"—39 [1]
impracticability of waiting years for them,

accelerated aging was employed. This method

produces, in a relatively short time, effects simUar to those arising from long periods of natural aging. The conditions used are qualitatively similar to those encountered in service,

but are made much more drastic in order to produce results quickly. Experience at the

Bureau with record papers ^ and with roofing

materials and fiber building boards ^ has

demonstrated the usefulness of accelerated

aging for predicting the permanence of fibrous

materials. It is believed that the procedm-e is applicable in this instance.

II. DESCRIPTION OF SAMPLES

The papers studied in this investigation were

obtained from cooperating manufacturers.

They were selected and obtained with the assist- ance of the National Lumber Manufacturers

Association. Inclusion of all commercial brands was not deemed necessary, but effort was made

to secure samples of current production that

would be representative of all the types in common use in house construction. Twentyone papers from seven manufacturers were

tested. These may be divided into the following

four groups, some of which comprise several

types and weights.

1 . Laminated Paper Products

The largest group was composed of nme

lammated papers consisting of two or more

plies of paper cemented together with asphalt.

The asphalt, in addition to functionmg as the

adhesive, binding the plies together, acts as the

principal moisture barrier. As further protection against moisture, some of the papers had

one or more plies saturated with asphaltic

material. With the exception of one three-ply

paper, all of the laminated products were of two-ply construction. Four papers contained

reinforcing cords between the plies to add

strength.

2. Single-Ply, Asphalt-Treated

Six samples were papers impregnated with

asphalt to render them resistant to moisture.

' BS J. Research 7, 466 (19:51) RP352.

' BS J. Research 11, 727 (1933) RP620.

6 J Research NBS 18, 669 (1937) RP1002.

' Building Materials and Structures (1938) NBS Rep. BMS4

The base papers in this group included mediumweight kraft, comparable to kraft wrapping

paper, light-weight roofing felt, and paper

made principally of asbestos fiber.

3. Metal-Foil Laminated Products

A third group consisted of laminated products made up of one layer of thin metal foil and one or more layers of kraft paper cemented

together with asphalt, with or without reinforcing cords. This type of sheeting is a comparatively recent commercial development.

4. Rosin-Sized Paper

Only one paper that had not been treated

after manufacture to enhance its resistance to moisture was included. It was a paper of the

type known to the trade as "red rosin sheathing." This is simply a coarse paper of the

general nature of heavy wrapping, sized with

rosin for water resistance and pigmented dull

red for identification.

III. DETERMINATION OF STABILITY

BY ACCELERATED AGING

Sheathing paper as a component part of a

building may be subjected to wide variations

of temperature and humidity. The seasonal

variations of temperature are often greater than

55° C, and the hygroscopic condition may vary

from extreme dryness during hot weather to actual wetness from water infiltration. The

accelerated-aging treatment which subjected

the sheathing papers to an intensified simulation of normal weathering consisted of the

following cycle: Oven drying at 65° C for 3 hours; immersion in water at room temperature for 3 hours; freezing at —12° C for 18

hours. This treatment was continued for a

total of 600 hours, 25 cycles, and the effects measured.

The accelerated-aging treatment was designed

to produce results similar to those arising from

normal weathering and did not include all factors which may produce deterioration under

limited or special circumstances. No attempt was made, for example, to determine the eflect of lime from wet plaster or mortar on the

papers. The destructive action of lime on aluminum is well known, and it is assumed that

[2]
tl)e aluminum-laminated papers will not be used

where they are subj ect to damage from this cause

The effects of accelerated aging, which constitute the yardstick by which the stability

of papers is measured, are obtained by observing the changes attributable to the treatment.

The aging produced cliiingcs in permeability

to water, water vapor, and air; in tensile strength; and in dimensions. The original

properties of the papers and the changes in

permeability and strength during aging are shown in table 1.

Table 1.

Properties of sheathing papers and some changes produced by accelerated aging

Papers

Type

a Tensile breaking

strength " E fleets of accelerated aging"

Oj2 ^

£; 2 «

a a c:

Descriptive remarks

3-ply asphalt- laminated,

reinforced.

2-ply aspbalt-

\ laminated,

reinforced.

2-pIy asphaltI laminated

notre-inforced.

1-ply asphalt- impregnated.

Ib/SOO

ft'37

IblSOO

ft'19

Percent 0.5

Iblin.

75

Laminated,

i with metal

foil.

Rosin-sized.

21

9.S

116

109

131

33

.fi .8

.7

5.8

C.6

5.

3.2

0.7

4.3

55.3

(')

(0

(')

(0

(0

16.0

67

46

68

44

76

37

4737

47

94

47

70

103

J 19

!02

220

39

Iblin.

42

38

79

114

90

216

27

Hours

36

44

36

10

36 Impervious

1/60

Impervious

1/60

2.5

1.8

1.9

3.6

3.3

1.9 6.5

1.7

0.5

126.0

8.5 22.0

1.6

8.0

Impervious

198.

.29

.02

.05

.14

.10

.02

87.00

7.30

2.70

2.50

0.08

1.30

Percent60

40

Percent50

Impervious

140. 00

I 17

3

{ 0

13

3

31

90

0

100

37

, No

/ change

lOU

2i hr5.4

11.0

12.5

7.0

00.6

0

3.3

0

44.

23.8

2.3

No

change

3 plies of kraft paper with re- inforcing cords.

2 plies of kraft with reinforcing

cords.

2 plies of kraft. asphalt-saturated, with reinforcing cords.

2 plies of kraft, with reinforcing

cords.

2 plies of kraft. Do.

2 plies of kraft, creped and

asphalt-saturated.

2 plies of kraft, 1 ply plain, 1 ply

creped and asphalt-saturated

2 plies, 1 ply plain kraft on 1 ply

of asphalt-saturated felt. 2 plies of plain paper, asphalt- treated by " KB" process.

,\sphalt-saturated felt. Asphalt-saturated felt, light- weight.

.Asphalt-saturated kraft. Asphalt-saturated and coated

felt. Asphalt-saturated asbestos

paper.

1 ply of aluminum foil and 1 ply of kraft.

1 ply of copper foil (1 oz), Iply

of kraft creped, and 1 ply of kraft plain. Same as Qi, except with 2-oz copper foil.

1 ply of copper foil (2 oz), 1 ply

of creped kraft with rein- forcing cords. Same as Ri. except with 3-oz copper foil.

Rosin-sized, not asphalt

treated.

» Tensile tests made on pendulum-type, power-driven machine. Spec- imens 1 in. wide; testing length, 3 in. Water penetration determined by dry indicator method. TAPPI

Std. T433m, Tech. Assn. Pulp & Paper Ind., 122 E.42d St., New York, N. Y.

o Method for moisture vapor permeability proposed by Subcommittee, Tech. Assn. Pulp & Paper Ind., Brabender, Paper Trade J. 108, No

4 (.Tan. 19.39).

d Air permeability determined with Carson precision permeability

tester. BS J. Research 12, 567 (1934) RP681.

Accelerated aging consisting of 600 hr of cyclic treatment. Each

cycle =oven-drying at 65° C, 3 hr; immersion in water, 3 hr; freezing

at -12° C, 18 hr.

' Foil papers were not ashed.

[3]
Figure I.— Precision instrument for incasiiriiig the air permeability of papers.

1. Permeability to Air, Water, and Water

Vapor

One of the important functions of sheathing

paper is to prevent infiltration of air as a result

of wmd pressure. All papers tested had comparatively low permeability, apparently so low

that the infiltration thiough any of them, if they are properly installed, would be an insignificant factor in the loss of heat from the structure. Accelerated aging changed the permeability in some instances, but the changes were

relatively small, and the papers apparently re- tained sufficient resistance that their utility

in this respect was not impaired to any appreciable degree. Measurements of air permeability were made with the precision permeability in- strument developed by Carson.* The apparatus is shown in figure 1. In view of the importance of its function as a

barrier against the infiltration of water, the

necessity for sheathmg paper to retain its re- sistance to water is apparent. Wet walls are no more welcome in a house that has been

erected for 10 years than in a new one. The papers varied quite widely as regards

both the initial permeability to water and the

retention of water resistance after accelerated

aging. As a class, the metal-foil laminated

papers were the most satisfactory in both

respects. They were all impervious, as de-

» BS J. Research 13, 567 (1934) RP681.

termined by the available methods, and re- mained so after aging. These papers are, however, much more expensive than the other types

and are not strictly comparable for that reason. The two- and three-ply papers had good

initial water resistance; but, with one exception,

these papers lost 70 percent or more of their

resistance under accelerated aging. This was

apparently due to some separation of the plies,

which partially broke the asphalt seal. The

exception was a duplex paper, one ply of which was a saturated felt and the other a kraft paper.

This sample contained 78 lb of asphalt per 500

sq. ft, moi-e than three times as much as any of the other laminated papers. It was impervious

to water and was apparently unchanged in this respect by aging.

The single-ply papers had, in general, a rela- tively low initial resistance to water. In only one instance was the time required for transu- dation of water greater than 8 hours . However

,

the water resistance was retained exceptionally

well after accelerated aging.

Resistance to the passage of water was determined by the dry-indicator method.^ An indi8 TAPPI standard T433m, Tech. Assn. Pulp & Paper Ind., 122 Ea.sf; 42d St., New York, N. Y.

Figure 2.The dry indicator- test for determining the resistance of sheathing papers to the passage of water.

[4]
cator consisting of a mixture

of eosin dye, powdered sugar, and starch is sprinkled on

one surface of a 6-in. square

of the paper, and a glass cover

is sealed over it to prevent

nioistiu-e reaching the dye

except through the paper.

The specimen, with edges

turned up to make a boat,

is then floated on water. The time of transudation of

sufficient water to develop

color in the indicator is a measm-eof the relative resist- ance to water penetration.

Figure 2 shows the test in progress. With the increasing application of air conditioning to house construction, the importance

of a moistm'e seal to prevent escape of moisture

from within has been stressed. The seal is important for two reasons: It aids in holding suit- able humidity within the structure; and it pre- vents the inside moisture from penetrating

through the walls to condense within them

during cold weather—a condition which may

become very serious in some types of construction.

In respect to permeability to water vapor the

results followed roughly those for water penetration in that the papers of low permeability

to water usually had correspondingly low per- meability to vapor. Here again the metal-foil

papers were impervious both initially and after accelerated aging. Also, paper Z, which was

impervious to water, had the best resistance to the passage of vapor of all samples except the

foil papers. All papers which showed serious

increase in permeability to water vapor during

aging also showed serious loss of water resist- ance. The last column of figures in table 1 gives the increase in permeability to water vapor

as a change in magnitude rather than as a percent. Otherwise, a paper such as ZZZ, which

after aging was a good vapor barrier, would be

unfavorably compared with T^', which had little to lose. Measurement of permeability to water vapor was made hy a method developed recently by a committee of the Technical Association of the

,;«|i|j|||ggf

Figure 3. —Testing the permeability of sheathing papers to moisture vapor.

Pulp and Paper Industry.'" The test specimen

is used as a cover for a 95-mm petri dish containing anhydrous CaCl2 as a desiccant. The

specimen is sealed in place with wax and the

assembly is inverted and placed in a room at 65-percent relative humidity and 21° C. The

assembly is weighed periodically until the

rate of gain in weight is constant, and this rate

is rei^orted. Figure 3 shows this test in progress, with specimens in place on the petri dishes.

2. Strength

Sheathing papers should have ample strength

to stand the required handling during installation without injury. After a paper is in place

in a structure, it is not subject to the sort of

stresses that would cause failure, and in no

instance is a paper called upon to add strength

to the structure. Tensile-brealdng strength

measurements were made on the papers to find the comparative strength, and the loss of

strength during aging was obtained as an indication of stability. It is of interest to note

that large effects of accelerated aging on the

strength were usually accompanied by considerable loss of resistance to water. The metal-foil

papers were little afl'ected, as might be expected,

inasmuch as the strength of papers of this class

is largely that of the foil. The reinforced laminated papers lost considerable strength on

aging, the average loss being approx-imately 50

ii> G. J. Brabender, Determininc -water vapor permeability of sheet

materials. Paper Trade J. IflS, No. 4 (Jan. 26, Vm).

[5]
Figure 4.

Shrinkage of sheathing papers after cyclic

wetting and drying.

percent. With the exception of sample WW,

the retention of strength by the duplex papers

without reinforcing cords was much better, the

loss ranging from 9 to 23 percent. The singleply papers held up well, except samples Y and

YY, which had less than 10 percent of asphaltic

components. The data on loss of strength

appear to be of value only as an indication of

the general stability of the papers, since all of

the papers retained sufficient strength for purposes of utility as far as ordinary applications are concerned.

Tests of tensile strength were made on a power-driven tensile machine of the penduhmi

type. The test specimens were 1 in. wide and

the testing length was 3 in. The speed of the

loading jaw was 12 in. per minute.

3. Shrinkage

The usefulness of a sheathing paper as a

barrier to the passage of air and moisture will be seriously impaired if, after installation, the

joints should open through shrinkage. A practical test of shrinkage was made by wetting and

drying specimens of the paper nailed on frames

15 in. square. After three cycles of wetting

and drying most of the papers remained intact .

A few, however, shrank excessively and pulled

away from the nails, as shown in figure 4. The

rates of shrinkage of these few papers in comparison with several which did not loosen were

studied in more detail. Strips, 6- by 24-in.,

taken both in the machine direction and the

cross direction, were immersed in water for 1 hour and allowed to dry without tension. The

apparent change in length after a given number

of cycles of wetting and drying are given in

table 2. In this table the first five papers are those which pulled away from the nails on the

frames.

Table 2.Shrinkage of sheathing papers

Shrinkage ^

Paper » 10 cycles 20 cycles 30 cycles

Machine Cross Machine Cross Machine Cross

direction direction direction direction direction direction

Percent Percent Percent Percent Percent Percent .ST 1.5 4. 5 2.0 5. 5 4. 0 CO

1.5 3.

1

2.0 3.9 2.0 4.0

1' 0.6 0.0 1.0 1. 3 1.0 1.3 YY .9 1. 1 1.

1

1. 4 1.

1

1.5 zz 3.2 1.

1

5. 2 1.1 6.0 T. o' 0 U 0 0 Q 0 0 z 0 0

Papers ST to ZZ, inclusive, shranlc sulBciently in a previous test to pull away from the nails when nailed over frames 15 in. square and sub- sequently wet and dried. The other papers remained intact under the same test.

t Each cycle consisted in immersing in water 1 hr, then air-dryini^ with- out tension.

IV. SUMMARY AND CONCLUSIONS

Many of the sheathing papers do not retain

their resistance to the passage of water and

water vapor satisfactorily imder accelerated

aging. This is important because, in modern

house construction, the paper is depended

upon as the principal barrier to the passage of

vapor from within, and to a considerable

degree as a barrier to the infiltration of water

from without.

The laminated papers were, with one exception, relatively imstable as regards retention of

water resistance. The apparen t failure of these

papers to retain their resistance to water and

vapor may be attributed to partial separation of

the plies, causing breaks in the asphaltic layer.

The one paper of this type that did perform

satisfactorily was a saturated felt with one ply

of plain kraft paper cemented to it with asphalt.

[6]
The saturated felt was relatively heavy and

carried much more asphalt than any other

paper. This paper had excellent initial properties and it was practically unaffected by aging.

The results obtained on the single-ply asphalttreated papers indicate that papers of this class should carry not less than 20 lb of asphalt

per 500 sq ft for satisfactory resistance to water and vapor. The two saturated felts, U, and V, showed little change on aging; but

the initial resistance was not satisfactory in the

instance of V, which was lighter in weight and

carried less asphalt.

Paper T, which was saturated and coated

with asphalt, was quite satisfactory.

The metal-foil papers as a class were highly

satisfactory with respect to the initial properties

and their resistance to aging. These sheetings were impervious to both water and vapor, as determined by the available test methods, and were unaffected by the aging treatment, ft should be remembered, however, that alkalies

attack aluminum readily under some conditions, and that aluminum foil should nev(!r be

used where wet plaster, stucco, or other masonry

will come in contact with it. The asphalt-treated asbestos sheeting did not

differ essentially from saturated felt of comparable weight as regards strength and resistance

to water and its vapor. The rosin-sized papei'

showed unsatisfactory resistance to accelerated

aging.

Washington, August 15, 1939.

[7]

i
I
BUILDING MATERIALS AND STRUCTURES REPORTS

The following publications in this series are now 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 10^ 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 150 BMS6 Survey of Roofing Materials in the Southeastern States 15^ BMS7 Water Permeability of Masonry Walls 100 BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 100 BMS9 Structural Properties of the Insulated Steel Construction Company's "Frameless-Steel"

Constructions for Walls, Partitions, Floors, and Roofs 100 BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Company 100 BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 100 BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 150 BMS13 Properties of Some Fiber Building Boards of Current Manufacture 100 BMS14 Indentation and Recovery of Low-Cost Floor Coverings 100 BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored by

the Wheeling Corrugating Company 100 BMS16 Structural Properties of a "TUecrete" Floor Construction Sponsored by Tilecrete Floors, Inc 100 BMS17 Sound Insulation of Wall and Floor Constructions 100 BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation 100 BMS19 Preparation and Revision of Building Codes 150 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 Company 100 BMS23 Structural Properties of a Brick Cavity-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 WaUs, Partitions,

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

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

Bender Body Company ^ 100 BMS28 Backflow Prevention in Over-Rim Water Supplies 100 BMS29 Survey of Roofing Materials in the Northeastern States 100 BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas

Fir Plywood Association 100 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by the Insulite Company 150 BMS32 Structural Properties of Two Brick -Concrete -Block Wall Constructions and a Concrete-Block Wall Construction Sponsored by the National Concrete Masonry

Association 100 How To Purchase

BUILDING MATERIALS AND STRUCTURES REPORTS

On request, the Superintendent of Documents, U. S. Government Printing Office, Washington, D. C, will place your name on a special 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 the 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 report 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.