U. S. DEPARTMENT OF COMMERCE

BUILDING

MATERIALS

AND

STRUCTURES

REPORT BMS50

Stability of Fiber Building

Boards as Determined by

Accelerated Aging

by

DANIEL A. JESSUP,

CHARLES G. WEBER, ^/^^

SAMUEL G. WEISSBERG
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 ON TECHNICAL RESEARCH

Walter Junge, Chairman. A. C. Shire, 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,

Federal Home Loan Bank Board. (Federal Loan Agency).

Carroll W. Chamberlain,

Public Buildings Administration (Federal Works Agency).

Joseph M. DallaValle,

Public Health Service (Federal Security Agency).

John Donovan,

Farm Security Administration (Agriculture).

Vincent B. Phelan,

National Bureau of Standards (Commerce).

Edward A. Poynton,

Office of Indian Affairs (Interior).

George W. Trayer,

Forest Service (Agriculture).

Elsmere J. Walters,

Construction Division (War).

CHAIRMEN OF SECTIONS

Specifications Maintenance

Carroll W. Chamberlain Charles Peters

Mechanical Equipment

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 OE COMMERCE I larry I.. 1 1-,,, kins, Secretary

NATIONAL BUREAU OF STANDAKI^S • Lyman J. Briggs, Director BUILDING MATERIALS

W STRUCTURES

REPORT BMS50

Stability of Fiber Building Boards as Determined

by Accelerated Aging

by

DANIEL A. JESSUP, CHARLES G. WEBER,

and SAMUEL g. weissberg

ISSUED MAY 13, 1940

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

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

UNITED

FOR SALE

STATES GOVERNMENT PRINTING OFFICE • WASHINGTON

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

1940

CENTS
Foreword

Vegetable-fiber boards, which have wide application in house construction, were

subjected to accelerated aging to find their probable stability or lasting qualities. The

physical properties of the materials in this class were described in an earlier report in this

series, BMS13, and the present report contains data on the changes in those properties

produced by accelerated aging. These changes are used as a basis for judgment of

relative stability.

Lyman J. Briggs, Director.
Stability of Fiber Building Boards as Determined by Accelerated

Aging

by

DANIEL A. [RSSUP, CHARLES (i. WEBER, S A M U E I, V, . WEISSliKR(;

Foreword

I. Introduction

II. Description of samples^

III. Properties and testing

1. Thermal insulation

2. Flexural properties

3. Nail-holding strength.

4. Water absorption

CONTENTS

III. PageII Page Properties and testing—con tin uerl

.5. Water permeability.- 4

6. Air permeability 4

7. Outdoor weathering 4

8. Moisture-con tent-relativc- uimidity re- lationships 5

9. Resistance to rot-producii g fungi 5

10. Chemical properties _ _ 6 Summary and conclusions. _ . _ 6

ABSTRACT

Fiber building boards were aged by exposure to cycles of wetting, freezing, dr3'ing, and baking and to outdoor weathering. The boards were tested before and after aging to determine the changes produced, and

judgment of stability was based on the changes. The

properties tested were weight, thickness, expansivity,

thermal conductivity, flexural properties, nail-holding

strength, water absorption, ash, rosin, and permeability

to air and water. Data were obtained on the relation- ship between the moisture contents of the boards and

the relative humidity of the siUTOunding air and on the

resistance of the boards to rot-producing fungi. In general, the retention of the most essential properties—namely, thermal conductivity and strength—was

excellent. Furthermore, the boards did not support

the growth of rot-producing fungi except at relative humidities above 85 percent. At the high humidities, the fiber boards are subject to mold growth, but it was shown that the growth can be prevented, or at least appreciably retarded, by use of fungicides.

I. INTRODUCTION

Fiber building boards have been tested in connection with the research on building

materials and structures for low-cost housing.

Previous publications have described the properties ^ of various commercial boards and the

tests - used for detemiining the stability of

them. This article presents the results of

tests on the stability of commercial products

furnished by the manufacturers as representative of the boards now on the market. The

relative resistance of the different boards to deteriorative influences was judged by the

effects of accelerated aging and outdoor weathering exposures and by the resistance to rot- producing fungi under controlled conditions.

1 Building Materials and Structures (1939) NBS Rep. BMS13-

(Price, 10 cents.)

2 Building Materials and Structures (1938) NBS Rep. BMS4. (Price. 10 cents.)

Data on relative-humidity-moisture-content re- lationships were obtained also. Some of the most important properties of the boards are thennal insulating value; resist- ance to the absorption of moisture, which causes

swelling and warping of the board; nail-holding

strength; resistance to air infiltration; and

flexural strength. Fiber boards were known to be generally satisfactory in these respects

when new, and the retention of their properties

under the aging treatments was taken as the

criterion of the resistance to aging.

II. DESCRIPTION OF SAMPLES

The boards tested in this investigation were obtained from cooperating manufacturers. Not all of the commercial brands were tested, but those

included are considered to be representative of

the types available commercially. Eleven manufacturers submitted 17 difterent boards for test.

220368°—40 [1]
All of the boards tested were of the lowdensity class, desig-ned to provide thermal

insulation. They were the K-inch boards for use within walls or for ulterior finish. For sake

of convenience in comparing test results, they

are classified into three groups according to composition and finish; however, the general

characteristics of all boards are essentially

comparable.

III. PROPERTIES AND TESTING

Insulating boards, when used as a component part of a building, are exposed to wide

variations of temperature and moisture. Accelerated aging ^ was employed to find the probable stability of the boards under such influ- ences. They were subjected to an intensified

simulation of normal aging. The treatment

consisted of the following cycle: Immjersion in water 1 hour; spraying with condensed steam

at 90° to 95° C for 3 hours; storing 20 hours

at -12° C; heating 3 hours at 100° C in dry

air; again spraying with condensed steam at 90° to 95° C for 3 hours; and heating in dry air at 100° C for 18 hours. This cyclic treatment was continued for a total of 300 hours.

Insulating board is not, in general, designed

for use as exterior finish. However, since

receipt of a large number of inquiries regarding

its suitability for this purpose has indicated

widespread interest in it, a number of exposure

tests were made. During the tests, water was

sprayed on the samples at regular intervals to accelerate the natural weathering. The edges

of the boards were sealed against moisture by

a coating consisting of powdered aluminum in spar varnish. Two specimens of each board

under test were subjected to the outdoor ex- posure. The surface of one specimen of each was painted with a linseed oil-white lead paint

suggested by the Bureau's paint section. The

second specimen of each board was exposed

' 8ee footnote 2. Table 1.-

with no protection of the surface.

-Properties of fiber building boards and effects of accelerated aging

Laboratory

designation of board

Flexure properties

Breaking load

Across

long

direction

Across

short

direction

Deflection at rupture

Across

long

direction

Across

short

direction

Nail- holding

strength

(lateral)

Water

absorption, by

volume

(2-hr immersion)

Water

permeability (time of penetration through

board)

Air permeability (rate of flow

through board)

BOARDS MADE PROM CROP PLANT WASTES AND WASTE PAPER

Btu/hr cm cm 3/sec in. lb/ft 3 % % % ft 2 CF/in.) lb lb lb lb in in in in lb lb % % hr hr m'io/cm') A 0.49 16.9 2.8 2.0 0. 15 0. 35 14.3 11. 1 11.3 9.0 0. 72 0.93 0.76 1. 14 74 63 5.7 76.0 25 0. 13 454 593 H .49 25.6 1.6 ,3.6 .20 .43 33. 3 26. 5 32.5 28.0 .85 1.02 .72 0. 86 143 115 4.1 4.0 47 45 30 48 K .51 16. 5 8.2 2.

1

.30 .37 10.5 7.8 12.1 8.7 .54 .56 . 57 .57 64 50 4.2 63.0 6 1 700 743 M .51 15.7 0.9 1.6 .10 .37 17.2 11.0 11.3 4.7 .52 .75 .57 .71 67 54 6.3 78.0 5 0.16 383 371 R .48 18.2 4.2 4.6 .40 .36 15.3 12.7 14.6 12.1 .98 1.70 1.05 1.47 83 64 5.3 78.0 5 1 479 459

.53 21.8 3.0 25.8 .40 .40 20.5 21.1 20.7 22.3 1.27 1.06 1.32 0.93 112 115 3.4 6.7 6 4 760 802

BOARDS MADE OF WOOD FIBER B 0.50 16.2 0.6 3.3 0.20 0. 34 16.5 12. 5 13.0 10.6 0.60 0. 77 0. 72 0.85 72 61 12.5 76.0 6 0. 03 1,084 1,350

/b .52 16.9 .6 5.4 .15 .36 25.4 17.

1

18.0 13.8 .54 .79 .64 .81 95 75 5.6 5.0 30 16 505 673 J .53 16.6 .5 2.6 .20 .34 20.6 17.7 15.6 14.3 .52 .75 .68 .87 87 79 7.9 74.0 21 0. 36 498 595 L . 51 18.8 .3 5.5 .20 .37 17.0 13.4 16.9 12.4 .34 .39 .37 .39 71 62 4.7 5.6 16 6 3, 300 3, 540 .47 16.5 1.0 3.0 .10 .33 9.7 5.6 10.5 6.2 .50 .43 .48 .59 57 31 5.4 3.6 22 20 1,215 1,945 0 . 55 17.0 0.7 2.3 .20 .33 12.2 10.9 11.4 10.5 .55 .77 .50 . 72 87 70 6.8 23.0 25 9 2,665 3,480

INTERIOR-FINISH BOARDS WITH SPECIAL SURFACING ON ONE SIDE c 0. 47 21.0 2.4 5.4 0. 35 0. 39 14.4 10.1 14.0 9.5 0. 61 0.83 0. 89 0. 92 72 59 5.1 4.9 26 10 676 1,260 D .48 16.9 3.8 2.7 .30 .36 15.1 10.0 11.4 10.1 .83 1.27 .89 .90 79 70 9.0 71.0 18 0.05 207 313 P .46 20.7 2.3 3.2 .40 .35 12.0 9.6 12.

1

10.0 .77 0. 88 .97 1.07 94 75 9.3 7.3 21 12 704 1,940 JJ .50 17.2 3.2 2.1 .20 .35 16.2 15.2 13.

1

11.8 . 71 . 79 . 72 0. 86 70 67 6. 2 7.0 12 6 328 537 RR .49 18.3 6.3 4.9 .40 .36 16.4 12.4 14.

1

11.6 .98 1.37 1. 10 1. 35 87 64 5. 6 71.0 5 1 339 416

a For specimens 6 in. wide oi

1) Impregnated with asphalt.

" Treated with wax.

[2]
Another factor affecting the sta,bility of fiber buildmg boards is their susceptibility to rotting.

The boards were tested for resistance to the

action of rot-produchig fiuigi by inoculating

specimens with three of the typical rot-producing fungi commonly found around wood

constructions; storing the specimens under

warm, moist conditions favorable to the growth

oi the fungi ; and observing the spread of the

fungi and their eflV'cts on the boards.

Data on the various properties of the boards

before and after accelerated aging are shown in table 1 . A comparison of the data for the aged

and unaged samples gives an indication of the

relative stability. Since the methods of test- ing have been given in detail in previous publications and in a Federal specification for insulating boards, they are described only

briefly here. y

1. Thermal Insulation

The insulating value of a board depends

upon its thickness and the thermal conductivity

of the material of which it is ^Omposed. In

any given thiclmess, the insulting value is in- versely proportional to the thermal conductivity

of the material. Conductivity is expressed as the number of heat units (Btu) that would be

transferred through 1 square foot of the board

in 1 hour with a temperature drop of 1° F per

inch of thickness.

Measurements of thermal conductivity were made by the guarded hot-plate method pre- viously described. The tests reported were made by H. W. WooUey of the Heat Transfer

Section of the Bureau.

The accelerated aging of the boards had no

appreciable effects on the insulating value, as indicated by the results of thermal-conductivity

measurements.

2. Flexural Properties

The }2-inch insulating boards are not usually

installed where they are required to contribute

materially to the strength of the structure. A

reasonable flexural strength is required for economic handling and installation without

undue breakage, and the boards must retain

enough strength and rigidity to prevent dam-

' See footnotes 1 and 2.

s Fed. Spec. LLL-F-321a, Fiber Board; Insulating.

age to the walls through sagging or \>vi':\k\\\<^ of

tlie boards after installation. 'I'lic IIcmiihI strengtli wiis determined l)y I lie mh iIioiI iIcsci'il)e(l in the Fedei'al specific!i,tioii loi' insidatiug

boards and hi the previous Burciui |)iil)lic,ation."

The method consists in loading at midsinui a specimen 3 inclies wide, supported by two paiallel supports 12 uiches apart, until the si)ecimen breaks.

Decreases in flexural strength were not large

except for boards M and N. The initial strength of was relatively low.

3. Nail-Molding Strength

Nail-holding strength is of interest as it indi- cates the probable danger of the boards hecoiii- ing loosened after installation. The test method

consists essentially in measuring the foi-ce i-e- quired to move a 6-penny common nail to llic edge of a board from a position %-hich from the

edge.

Aging caused losses of nail-holding strength

for most of the boards, but in most instances

the losses were not serious. Board A'^ suffered

the greatest loss, and it had relatively low nailholding strength initially.

4. Water Absorption

Water absorption is an important factor in

the usefulness of fiber building boards, because

it indicates the extent to which the fibers will become wet when moisture reaches them. Wetting is accompanied by swelling of the fibers,

and warping or buckling of the board may result. Most insulating boards are sufficiently

resistant to wetting when new; however, if the

absorption should increase appreciably after

installation, the usefulness of the boards would

be impaired. The water absorption was determined by the method defined in the Federal

specification for insulating boards.

Specimens are weighed before and after immersion in water for 2 hours. The resulting

increase in weight indicates the amount of

water absorbed and is reported in percentage

of the volume of the specimen before immersion. There was considerable lack of unil'oijnitv

with respect to the eft'ects of agmg on tli(>

8 See footnote 1.

[3]
water absorption of different boards. Two of

those in group 1 were practically unaffected,

whereas the other 4 showed a rather sharp in- crease. Of the 11 boards in groups 2 and 3, 5 showed sharp increases, and the others were

unchanged.

5. Water Permeability

Insulating boards are not commonly used

where they must function as a moisture barrier. However, the rate of water penetration

is often important because it may contribute

to the resistance of the finished walls to the infiltration of water. The rate of penetration of

water through the boards was determined by

the dry-indicator method. An indicator consisting of a mixture of eosin dye, powdered

sugar, and starch is sprinkled on one surface

of the specimen ; a glass cover is sealed over the

indicator; and the edges of the specimen are sealed with wax to prevent water from reaching the indicator except by penetration through

the board and to prevent evaporation of the

transuded moisture. The specimen thus pre- pared is floated on water, and the time of transudation of water in an amount sufficient to develop color in the indicator is a measure of

the permeability.

The results of this test placed the samples in

much the same order as did the results for water absorption.

6. Air Permeability

Permeability to air may be important in its relationship to the insulating value of a fiber board. The infiltration of air causes a transfer of heat in addition to that transmitted by

thermal conduction. The permeability was

determined with the Carson precision permeability tester described in a previous Bureau

publication.^ The volume of air that will flow

through a board per unit area for a given pres- sure gradient is measured by means of a capillary flow meter. Changes in permeability to air with aging were small for specimens in groups 1 and 2. The boards designed for use as interior finish showed changes of considerable magnitude after aging because of breakdown of the surface

finishes. This deterioration does not appear

important, as when the boards are in use they

presumably will be redecorated from time to time.

7. Outdoor Weathering

Table 2 contains data on the comparative

results of tests after accelerated aging and after 15 months' exposure to outdoor weathering.

The results of the outdoor aging appear to be

roughly comparable to those of accelerated

aging. Diff'erences were large in a few instances

with respect to water absorption and water

penetration. It could not be expected that like values would be obtained by the two aging

treatments. However, the similarity of the

trend of results produced by the two methods

indicates that the effects of outdoor weathering

are comparable to those obtained by the more

rapid and convenient method of accelerated

aging. The boards which had been painted on

the exposed surfaces were little affected after exposure for 15 months.

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

Table 2.

Comparison of effects of accelerated aging and outdoor weathering »

Water absorption by volume Water permeability Air permeability Flexural strength Nail-holding strength

Board

Initial

After

accel- erated aging

After

out- door

exposure

Initial

After

accel- erated aging

After

out- door

exposure

Initial

After ac- celerated aging

After

out- door

exposure

Initial

After

accel- erated aging

After

out- door

exposure

After outdoor

exposure

(painted)

Initial

After

accel- erated aging

After

out- door

exposure

After outdoor

exposure

(painted)

D

%

9 %71 %44

hr.18hr.

0. 05

hr. 5 207 813 434lb.15lb.10lb.14lb. 15

lb.75lb.63lb.73lb. 83 H 4 4 5 47 45 30 30 47 31 33 28 28 32 143 115 115 123 / 6 5 15 30 16 7 505 673 654 18 14 14 24 95 75 73 96 N 5 4 7 22 20 7 1, 215 1,945 1. 560 10 5 8 15 57 31 40 64 P 9 7 23 21 12 5 704 1,940 2. 160 12 10 9 15 94 75 69 75 RR 5 71 10 5 1 7 479 439 435 14 12 14 16 87 64 86 84

» Values showing properties after outdoor exposure were obtained on samples too small for standard tests and values are approximate.

[4]
8. Moisture - Content—Relative-Humidity

Relationships '

The fiber boards are seldom in direct contact

with water for long periods; however, the air in contact with them may vary from a dry

condition to one near the saturation point.

The moisture content of a board is controlled

by the condition of the surrounding air and is important as it affects such properties as thermal conductivity, resistance to rotting,

and strength.

Relative-humidity-moisture-content relationships were determined for six typical boards,

representative of the different types under

study. The specimens were conditioned to constant weight at 95-percent relative humidity,

then at seven other humidities in order of descending values, the lowest condition being

15 percent. The conditioning was accomplished in a cabinet in which the humidity was

controlled by circulating the air over saturated

salt solutions. The specimens were arranged

to permit weighing without opening the cabinet.

Table 3 shows the relative-humidity-moisture-content relationships for the boards. It should be noted that the results for five of the

boards are very similar, but the sixth board

contained appreciably less moisture at each

humidity. This board is made from exploded

wood fibers and contains a large amount of natural resin, lignin, etc.

Table 3.

Eelative-hurnidity—moisture-content

relationship

[Desorption values!

Relative

huiiiidity

Moisture content of board

D H J K N L % % % % % % %

15 3.4 4.0 3.5 .3.9 3.8 2.7 17.5 .3.9 4. 5 3.9 4.4 4. 3 3.0

37 0.8 7.4 6.9 7. 2 7. 2 5. 1 48 8.2 8.7 8.4 8. 5 8. 4 6. 5

fl5 10. 7 11. 2 11.0 10.9 11.0 8.4

75 12.4 12. 9 12.8 12. 6 12. 7 9.7

88 15.2 16.8 1.5. 8 15.5 15.8 11.4 95 16.5 17. 2 17. 2 17.4 17.2 12. 2

9. Resistance to Rot-Producing Fungi

There has been much interest in the susceptibility of the fiber boards to rotting. Hence,

tests were made to determine under what conditions the boards will support the growth of

rot-producing fungi and the efi"ects of such

growths on the properties of I lie Itoaids. 'Hk;

selection of fungi was based on a rticonuncnrlation of the Division of forestry Pat lio)f)o-y,

IJ. vS. De|)artnient of Agriculture, iind I he cul- tures were prepared in the Forest J'.i I liolorry

Laboratory.

Specimens of fiber building boards inoculated

with the cultures of rot-pro(hicing fungi and

stored over water at ap])roxiniately 95-p(!rcent

humidity and room temperature showed changes

in nail-holding strength that were proportional

to the apparent extent of the growth. Those

showing only local stain were little aftected,

those with local decay showed considerable loss in strength, and those with general decay re- tained little or no nail-holding strength. Tliere was not much dift'erence in the rate and extent

of growth on aged specimens and the unaged

samples.

Fungus growth is generally considered to proceed most favorably under warm, moist

conditions. An effort was made to determine

the relative humidity most favorable to growth.

Specimens of the building boards were inoculated and stored in jars over saturated salt solutions selected to produce various relative

humidities. The specimens were weighed before storage and again after 4 months and the

changes were noted. Those stored at humidities below 88 percent showed no visible signs

of fungus growth and no significant loss in weight, but those conditioned above 88 percent

showed heavy growth and appreciable loss in weight.

When specimens were exposed in a jar at 33-percent relative humidity for 2 weeks, the

agar on which the fungus was grown dried and

showed no evidence of growth. However,

when the specimens were subsequently placed over water, the growth spread rapidly and continued to grow for the entire duration of the

test. This would indicate that if the material

has been infected with fungus, growth will not

progress if the relative humidity remains low,

but if high humidity prevails, growth will progress rapidly. Specimens of various species

of woods, including pine, cypress, fir, maple,

and walnut, were inoculated with cultures of

the same fungi used on the fiber boards and

stored over water with the fiber board speci-

[S]
mens. The apparent growth and spread of the

fungi on the woods were about the same as on

the fiber boards. Hence, it appears that the

fiber building boards are probably no more

subject to attack and decay by rot-producing

fungi than is the wood commonly used in house

construction.

Zinc chloride, lead acetate, a water-soluble

chlorophenolic compound, and an oil-soluble

chlorophenolic compound were used in a study

of the eftectiveness of some of the common

wood preservatives in preventing fungus growth

on fiber building boards. Specimens of the

boards were treated under reduced pressure

with solutions of the preservatives to obtain

retentions in the boards ranging from 0.1 to

1.0 percent. Specimens were conditioned to suitable moisture content, inoculated with the

rot-producing fungi, and stored in approximately 95-percent relative humidity at room

temperature. There was no apparent development of fungus on these specimens.

10. Chemical Properties

Tests for the cellulosic purity of the fiber boards did not produce results of value in esti- mating stability. The average initial alphacellulose content was relatively low and the

lignin content relatively high, approximately

50 percent and 20 percent, respectively. No

significant changes of these properties occurred

during aging. Apparently the chemical tests commonly used on fiber sheetings are of little value for measuring the deterioration of this type of board.

IV. SUMMARY AND CONCLUSIONS

The apparent stability of a number of fiber

building boards of current manufacture was

determined by observing their resistance to accelerated aging, outdoor weathering, and

attack by rot-producing fungi.

Accelerated aging produced large increases

in water absorption of some of the boards and in water permeability of most of the boards,

which indicates that they should not be

depended upon to function as a moisture

barrier.

The aging produced significant changes in

air permeability for most of the boards having

special surfaces for interior finish. The changes

resulted from a breakdown of the finish, and

since the boards, when in use presumably will be redecorated from time to time, no decrease in serviceability should result from this kind of deterioration.

Changes of nail-holding strength and flexural properties were not, in general, large enough to be considered serious under the aging treatment. The fiber boards are apparently no more

susceptible to damage from the growth of rot- producing fungi than are the woods used in house construction. Treatment of the boards

with a wood preservative will improve their

resistance to fungi.

The average stability of the boards under the

various deteriorative influences was relatively

good, but the results indicate that this type of board is not suitable for the exterior covering of buildings.

Washington, February 14, 1940.

[6]
BUILDING MATERIALS AND STRUCTURES REPORTS

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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 15^ BMS6 Survey of Roofing Materials in the Southeastern States 150 BMS7 Water Permeability of Masonry Walls lOjJ BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10^ BMS9 Structural Properties of the Insulated Steel Construction Go'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 Co 100 BMSll Structural Properties of the Gurren 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 Co 100 BMS16 Structural Properties of a "Tilecrete" 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 Co 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 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 BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas

Fir Plywood Association 10^ BMS31 Structural Properties of "InsuUte" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co

BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block Wall Construction Sponsored by the National Concrete Masonry Association. 10^

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

[Continued from cover page III]

BMS33 Plastic Calking Materials 10^ BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 10^ 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 Weston Paper and Manufacturing Co lOjS BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors, Sponsored by PaUsade Homes lOjS 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 lOfi BMS40 Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored

by Knap America, Inc 100 BMS41 Effect of Heating and Cooling on the Permeability of Masonry Walls lOjS BMS42 Structural Properties of Wood-Frame Wall and Partition Constructions with "Celotex"

Insulating Boards Sponsored by the Celotex Corporation 10(4 BMS43 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 lOyi BMS44 Surface Treatment of Steel Prior to Painting lOji BMS45 Air Infiltration Through Windows 10^ BMS48 Structural Properties of "Precision-Built" Frame Wall and Partition Constructions

Sponsored by the Homasote Co lOji BMS49 Metallic Roofing for Low-Cost House Construction 10^ BMS50 Stability of Fiber Building Boards as Determined by Accelerated Aging 100