Bureau of Standards
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 committee of principal technicians.

CENTRAL HOUSING COMMITTEE

ON RESEARCH, DESIGN, AND CONSTRUCTION

A. C. Shiee, Chairman.

United States Housing Authority.

Howard P. Vermilya, Vice Chairman.

Federal Housing Administration.

Sterling R. March, Secretary.

Pierre Blouke,

Federal Home Loan Bank Board.

Hugh L. Dryden,

National Bureau of Standards.

Loms A. Simon,

Public Buildings Administration.

Luther M. Leisenring,

Construction Division (War).

Edward A. Poynton,

Office of Indian Affairs,

John S. Donovan,

Farm Security Administration.

George W. Trayer,

Forest Service (F. P. Laboratory).

Joseph M. DallaValle,

PubUc Health Service.

George E. Knox,

Yards and Docks (Navy).

William R. Talbott,

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 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 Forest Service is cooperating with both

committees on investigations of wood constructions.

[For list of BMS publications and directions for purchasing, see cover page iii]
UNITED STATES DEPARTMENT OF COMMERCE • Harry L. Hopkins, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS55

Effects of Wetting and Drying

on the Permeability of Masonry Walls

by CYRUS C. FISHBURN

ISSUED SEPTEMBER 18, 1940

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

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

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • I94O

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

This paper gives the results of further studies of the resistance of masonry walls to penetration by dampness when exposed to wind-driven rain. The exposure of masonry

walls to wind-driven rains, with subsequent drying, produces changes in moisture content of the walls. Since the volume changes produced by the wetting and drying of

masonry units and mortars are unequal, differential volume changes may occur in the

masonry that result in the formation or enlargement of cracks in the joints. The effects of about 12 cycles of alternate wetting and drying on 8 small masonry walls have been

studied by measuring the permeability of the walls. The influence of exposure to local outdoor climatic conditions on permeability is also under study and the results will be

described in a subsequent report.

Lyman J. Briggs, Director.

[n]
Effects of Wetting and Drying on the Permeability

of Masonry Walls

by CYRUS C. FISHBURN

CON

Page

Foreword ii

I. Introduction 1

II. Description of the walls 1

1. Materials 2

2. Workmanship 2

III. Method of test 2

1. The wetting exposure - 3

2. Drying the walls 3

3. The observations 3

ENTS

Page IV. Effects of wetting and drying on the per- meability of the walls 4

1. All-brick walls .5 2. Walls with brick facings and hollowunit backings 5

3. Wall with stucco facings 5 V. Conclusions 5

ABSTRACT

Since the volume changes resulting from the wetting

and drying of masonry units and mortars are unequal,

changes in the moisture content of a masonry wall may produce differential volume changes between the

units and the mortar, resulting in the formation or enlargement of cracks in the joints. The effects of changes in the moisture content of 8 small masonry

walls were studied by measuring the permeability of the walls during each of about 12 cycles of wetting and

drying. The walls were wetted by applying water to

the exposed face simulating an exposure to a winddriven rain. The specimens were not subjected to

freezing during wetting or drying. Five of the walls were of all-brick construction, one was a stucco-faced

wall, and two were faced with brick and backed with

hollow units. There was no significant change in the

permeability of the walls resulting from the exposure to wetting and drying.

I. INTRODUCTION

Masonry building walls are frequently ex- posed to wind-driven rains that saturate the

exposed faces. Since mortars and some masonry units expand during wetting and shrink

in drying, it is probable that differential volume

changes occur between the units and the mortar

joints in those portions of the walls subjected

to wetting and drying. Such volume changes

may result in the formation or enlargement of

cracks in the masonry that permit the penetration of water into or through the wall. The

linear expansions resulting from the immersion

of dry and aged specimens of masonry materials in water are usually within the following

limits:

Linear expansion

Material (%) Bricks 0 to 0.01. Mortars and concretes"' 0.02 to 0.10. Brick masonry « 0.015 to 0.020.

" L. A. Palmer, Volume changes in brick masonry materials, J. Am.

Ceram. Soc. 14, 541 (1931). R. E. Stradling, Effects of moisture changes on building materials, Bui. 3 Brit. Bldg. Research Board.

' R. E. Davis, Proc. Am. Soc. Testing Materials 30, 668, appendix 13

(1930).

' W. K. Hatt and R. E, Mills, Bui. 34, Eng. E.\p. Sta. Purdue Univ.,

p. 18 (1928).

« R. E. Davis and G. E. Tro.xell, Proc. Am. Cone. Inst. 25, 210 (1929). Tests have been made on small masonry walls

at the National Bureau of Standards to determine the possible effects of exposures to heating

and cooling ^ and to wetting and drying on

permeability; this paper reports only the

eff'ects of alternate wetting and drying.

II. DESCRIPTION OF THE WALLS

Eight walls, about 40 in. long and 50 in. high, were selected from a group previously

tested for permeability and described in a publication ^ of the National Bureau of Standards.

I C. C. Fishburn and P. Petersen, Effect of Heating and Cooling on

the Permeability of Masonry Walls, NBS Building Materials and Struc- tures Report BMS41 (1940).

' C. 0. Fishburn, D. Watstein, D. E, Parsons, Water PermeabiUty of Masonry Walls, NBS Building Materials and Structures Report BMS7

(1938).

251302°—40 [1]
Five of the walls were of all-brick construction, one was a stucco-faced wall, and two

were faced with briclv and backed with hollow

units. Two kinds of brick, one stucco facing,

three kinds of hollow units, and four mortars were represented in the group of eight speci- mens. The wall thicknesses, the types of

workmanship, and the kinds of materials used,

are given in table 1. The designations appearing in the last column of table 1 will be used

to describe the walls in a subsequent table.

Table 1. —Description of the walls ^

Wall b Nominal

thick- ness

Kind

of facing

Kind

of backing

Kind

of mortar

Desig- nation "

li

in. § Brick a Brick a 1 aal

00 -- 8 do do 2 aa2

.^8 8 do do 3 aaS

51_-_ 8 do do 4 aa4 A6 12 Brick ft.... Brick 6.. _ bb2 A5 12 do Block m... 9 bm2

10 <i 12 do Tile d 2 bd2 7d 9 Stucco. _ . Tilej .... 2 sj2

» .All walls were of workmanship A as described in BMS7 Water

Permeability of Masonry Walls, except wall 10, which was of work- manship E, The wall numbers correspond to the original wall numbers in BMS7.

<! The first two letters denote the kind of masonry units used in the

facings and backings respectively. The numbers denote the kind of mortar used.

i Wall not flashed.

1. M.\TERIALS

Since complete information on the methods

of construction and the kind of materials used

in these walls is included in the publication

BMS7, only brief descriptions are given in this paper. The linear expansions or contractions

resulting from changes in the moisture content

of the materials or of the walls were not

determined.

Brick.—Brick a, used in walls 14, 60, 58, and

51 (table 1), was a low-absorptive side-cut

fire-clay brick having an absorption during a 24-hr cold-water immersion of 0.4 percent by

weight. Brick b was a side-cut shale brick

liaving an absorption of 8 percent.

Stucco.—The stucco facing of wall 7 was

mixed in the weight proportions of 1 part of Portland cement to 3 parts of building sand, and

it contained ammonium stearate in an amount

equal to 0.2 percent of the cement. Two coatings, each from % to % in. thick, were applied

24 hr apart to the tile backing of this wall. Hollow- Unit Backings. Block m, used in

wall A5, was a gravel-concrete block 8 by 12 by

8 in. laid on end. Structural clay tile d, used

in wall 10, was a 6-cell, double-shell end-bearing

unit, the stretchers being 8 by 12 by 10}^ in. Structural clay tile j was an 8 by 12 by 12 in. 6-cell unit laid on the side. Mortar.—The physical properties of the

mortar are given in table 2.

Table 2.

Physical properties of mortars

Properties of mortars Mortar 1 Mortar 2 Mortar 3 Mortar 4»

Proportions of cement,

lime, and sand: By dry weight 1:0. 11:2. 6 1:0. 42:5. 1 1:0. 85:7.7 1:0. 42:5.

By volume iJ.

. ... 1:0. 25:3 1:1:6 1:2:9 1:1:6 Average water content; percentage by weight of dry materials 19. 3 22.6 23.7 22.6 Compressive strength in 28 days (lb/in.2)= 2,850 640 2,';o 530 Flow after 1 minute of suc- tion on porous base (per- centageld . 86 95 97 95

= Mortar 4 contained 0.2 percent of ammonium stearate by weight of cement plus dry hydrated lime.

> Proportioning was by weight, assuming portland cement weighs

94 lb/ft 3, dry hydrated lime 40 lb/It and that 1 ft 3 of loose damp sand

contains 80 lb of dry sand.

" Cured according to Federal Specification SS -0-181.

^ Test made oa n mortar having an initial flow of 110 percent. Federal

Specification SS-C-181a.

2. Workmanship

Workmanship A was used in the construction

of all of the walls except wall 10, which was of workmanship E. For workmanship A, all joints were filled with mortar. Workmanship E was

similar to A, except that no mortar was placed

in the central 3 in. of both the bed and head

joints of the tile backing. Both workmanships

A and E are described in greater detail in BMS7.

All walls, except 7 and 10, contained copper

flashings so placed as to collect leakage passing

either through the wall or dropping between the

wythes. Because of the absence of those flash- ings in walls 7 and 10, it could not be determined ; if moisture appearing on the supporting channels at the back of the walls during a test had

penetrated the wall facings or had leaked

through the mortar joints between the walls

and the channels.

III. METHOD OF TEST

The extent to which exterior masonry building walls are afl'ected by wetting and drying

depends greatly upon their permeability, or

their resistance to penetration by heavy wind-

[2]
driven rains. Walls having a comparatively low

resistance may become permeated with water

within a few hours. Others, having a high

resistance, may become wetted only on the

exposed surface. The resistance to rain penetration of the group of walls described in this report was comparatively high as compared

with that of walls of ordinary or speculative

building construction, such as workmanship B,

described in BMS7.

The wetting exposure and the subsequent

drying that the test walls received during each

cycle of wetting and drying provided a range of moisture content in the masonry much greater

than would occur in most building walls of like construction. Rain and wind storms of an

intensity simulating the wetting exposure given

the test walls are infrequent and rarely last longer than a few hours. The test walls were

thoroughly dried to nearly constant weight

after each wetting exposure.

1. The Wetting Exposure

All of the walls, with the exception of A6

(broken at the end of 5 cycles), were given 10

or more cycles of wetting and drying, at temperatures above freezing. The wetting ex- posure is described on page 12 of BMS7

(Heavy Rain Test) and was designed to simulate the effects of a windstorm accompanied by

a heavy rain. Each wall was supported on

metal skids and clamped into position so that

the face formed one side of the inner walls of an airtight pressure chamber. Water from a

perforated metal tube was applied to the face

of the wall at the rate of about 40 gal/hr. An

air pressure of 10 lb/ft - above atmospheric

pressure was maintained within the chamber.

The wetting exposure was usually continued

for at least 1 day after the first penetration of

moisture through the wall, or for a maximum

period of 1 week. The relative humidity in the testing room averaged about 70 percent but

fluctuated somewhat with seasonal changes,

j In addition, also, the water applied to the walls

I (although heated during the winter months)

j was usually at a lower temperature than that

j[ of the air in the testing room. It is possible,

I therefore, that after one or more days of exi posure, the backs of some of the walls attained

dew-point temperature and condensation was

deposited upon them. However, during test B

(see table 3) the temperatures of both the water

and the air in the testing room were controlled

and there was no possibility of conck^nsation

forming on the backs of the walls, even though

the average relative humidity was about 80

percent.

2. Drying the Walls

After they were wetted, the walls were

placed in the drying room and bathed in heated

air, circulated by fans. Fresh air was constantly drawn into the drying room from outside and heated to a temperature of 40° to 50° F above the daily mean outside air temperature. The walls remained in the drying room until the rate of moisture loss was less than 3 lb (from 0.2 to 0.4 percent of the dry

weight) in 7 days.

3. The Observations

Data on the permeability of the walls were

obtained from observations made during the

wetting exposures. The following observations were obtained:

Elapsed time for the appearance of moisture

(dampness) on the backs of the walls. Elapsed time for the appearance of visible

water on the backs of the walls. Elapsed time for leakage to occur on the

lower flashings.

Maximum rates of leakage, if any.

Extent of damp areas on the backs of the

walls after an exposure of 1 day.

Observations were made at frequent intervals

during working hours and usually once each

night. Results of the observations are given

in table 3. Data from tests made both prior

to and after the wetting and drying cycles are included in the table. Test A corresponds to the "Heavy Rain Test," and data obtained

from it are discussed in report BMS7. The

average age of all the walls at the start and

finish of the wetting and drying cycles was 10

and 22 months, respectively. Test B was made

on five walls, aged 46 months, that had been

stored outside for 2 years after the completion

of the wetting exposures referred to by number

in table 3.
Table 3.

Data obtained from permeability exposures

Wall

60 b.

58 d .

A6..

A 5.,

aa3

bb2

bm2

Days

6

74

3

Time to failure as indicated by

hr 134±6 91±5 89±7

51±2 U2±5

123±1 111±5 86±6

102±1 111±6 n4±3

58±1 41±3

57±2

63±6

62±6 62±6

38±6

39±6

14±6 39±6 39±6

5.0 19±3

13±4

52±1

(«) ]4±C

39±6

15±6

15±6 10±2

15±6

18±4 24±1

0.37

. 18 .25

.33

1. 7 4.5

6. 7 5.5

3. 4 15±6

15±6

310±3 9±2

2328

2524

26

(»)

1. 3

0. 5

3. 3

4. 1 4. 2 10±3

0. 4

1. 2 40±6

18±4 1S±4

J2 O

Ar

a 5P

(=) (<=)

(«) (•) 15±3 18±3

15d=6 ]5±6

39±fi . ,

15±6 16±6 39±6

So

3 5f

Liters

0

0

0

0

0

0

0

0

00

0

0

0

00

0

0

0

0

0

0

0

0

0

0

0

0

(")0

0

0

0

0

00

0

0

00

0

0

0

0

0

00

0

0

0

0

0

0

0

0

0

(=)

0.1 0.4

0

0

0

0

00.6

0

0

0

0

Table 3.Data obtained from permeability exposures—-Continued

E

G

6

G-F, E

GE

GG

G

GE

G

G

G

G

G

G

GG

6

GG

GF

G

G

(-) G

GFF

F

F

G

G

G

GG

G

G

G

G

G

G

GG

G

G

0G

G

G

G

G

(•)F

F

G

G

G

G

FF

G

GG

G

» Ratings are arbitrary and are the same as those given in report BMS7.

The absence of flashings at the bottom allowing moisture to penetrate upward into the wall, or the formation of condensation on the back, may

have lowered some of the performance ratings of the less permeable walls from E (Excellent) to G (Good).

f> Break in wall near first header course between fifth and sixth tests (repaired).

» No data obtained.

i Repaired below first header course, between exposures 3 and 4.

• Wall broken in handling.

Wall

bd2

Days

4

Time to failure i indicated by—

hr 61±fi

39-tfi

65.-i:5 62±6

63±6

85±5 38±6

15±6

63±6 87±6

52±3

144±15 50±3

19±4 50±2

]12±5 G3±6 86±6

38±6

63±fi 90±10

Ul±fi 58±2

Ar

o.g

Ar

a?

Liters

0

0

00

0

0

0

00

0

0

0

0

0

0

0

0

0

0

0

0

0

0

G

G

GG

G

G

G

G

G

G

GE

GG

GG

G

G

GG

G

GE

IV. EFFECTS OF WETTING AND DRYING ON THE PERMEABILITY OF THE

WALLS

Masonry wall constructions may show a wide

range in permeability, as is indicated in table 4

of report BMS7. In this table the time interval required for the penetration of moisture or leakage through the different test walls ranged

from a few minutes for the most permeable

specimens to one or more weeks for the least permeable ones. Since visible water, extensive damp areas on

the back, or leakage through a wall might in- jure the finished interior of a building or damage

plaster applied directly to a wall, the rating of

the walls was judged by their condition at the

end of the exposure periods, time of first penetration of moisture being considered a minor

factor. The arbitrary wall ratings defined on

page 13 of BMS7 are largely dependent upon

the condition of the wall at the end of 1 day's

exposure.

The wetting exposure given the test walls is more severe than the natural exposure to which

most building walls are subjected, and the test exposures were often continued for periods

much longer than the duration of combined

[4]
heavy wind and rain storms. Although test exposures lasting more than 1 or 2 days, may

produce valuable data for comparing the per- formances of different wall constructions, their

practical value diminishes rapidly with continuation beyond 24 hours.

1. All-Brick Walls

The 8-in. brick walls Nos. 14, 60, and 58 were alike except for the kind of mortar. As

the bricks did not transmit water during the

exposures, the tests were measiu-es of the water

permeability of the joints, wall 14, containing

mortar 1 richest in portland cement, being the

least permeable and wall 58, containing the

high lime mortar 3, being the most permeable.

The proportion of the damp to the total areas,

at the end of 1 day, on the backs of walls 60,

58, and A6 fluctuated from test to test (especially wall 58), but did not show a consistent

tendency to increase or to decrease.

The first failure on the back of wall 51, during

exposures 1, 2, and 3, was a small leak that

stopped flowing within 1 hr after starting the

tests. There was no leakage from this wall

during amy of the later exposures, and the time

intervals for the first appearance of dampness

are considerably longer for the last 8 exposures

than for the earlier ones. Although the per- centages of damp areas did not show a consist- ent tendency to decrease, the increase in the

time for damp penetration indicated that the

permeability of wall 51 decreased slightly during the wetting and drying exposures. The

performances of the brick walls would be rated

good, according to the ratings in BMS7, with

the exception of some excellent performances

for wall 14 (exposure numbers A, 4, 6, and B)

and some fair ones for wall 58 (exposure numbers 1, 7, 8, 9, and 10).

The data in table 3 show that there was no

significant or consistent change in permeability

resulting from exposure of the all-brick walls

to alternate cycles of wetting and drying.

2. Walls With Brick Facings and HollowUnit Backings

Wall 10 was not flashed at the bottom, and

water appeared on the supporting channel

within 1 or 2 hr after starting each exposure.

The perfoi'inaiice of this wall was fairly uniform

for all test exposures and would be rated good

if the possibility of leakage through the wall were eliminated.

The performance of wall A5, table 3, was

better during the last three exposures, 9, 1(J, and B, than for any of the earlier ones; there was some leakage noted from the wall during

exposures A, 1, and 7. According to the rat- ings in BMS7, the wall could be rated good for

all test exposures except A, 1, 6, and 7. Although the data are meager, there is, however, a definite indication that the permeability

of wall A5 was slightly reduced, but not significantly changed, by exposure to wetting and

drying.

3. Wall With Stucco Facings

The performance of wall 7 was comparable to that of the least permeable brick wall, 14, and

could have been rated excellent for exposure

numbers A and B. Wall 7 was not flashed,

and moisture (damp areas) appeared at the bottom of the wall within 24 hr after the start of each exposure. The time intervals (table 3) for the first appearance of moisture on the back

of the wall are for areas that appeared above the

damp area located along the supporting channel. The data in table 3 show no significant

change in performance during any of the test exposures, and there is no evidence of any defi- nite increase in permeability resulting from the

exposure of the stucco-faced wall to wetting and

drying.

V. CONCLUSIONS

These conclusions pertain to the effect of

alternate wetting and drying on the permeability of a small group of masonry walls. The

walls were not subjected to freezing and thawing during the wetting and drying exposures,

and changes in their linear dimensions were not

restrained by adjacent structural members.

The exposures, therefore, tended to cause dif- ferential movements between the dift'erent materials in the walls and presumably tended to cause the separation of these materials and the

formation of cracks. However, these exposures
did not simulate all the conditions which sometimes cause a few lai'ge structural cracks in a

large wall. The exposure to alternate wetting and drying

had no significant effect on the permeability of

8-in. low-absorptive brick masonry walls. Although the data are meager, the permeability of walls with brick facings and hollowunit backings was slightly but not significantly

reduced by exposure to alternate wetting and

drying.

There was no significant change in the per- meability of a stucco-faced wall subjected to alternate wetting and drying.

Washington, April 2, 1940.

[6]
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

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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

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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 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 15(4 BMS7 Water Permeability of Masonry Walls 10(S BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10(4 BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs 10y4 BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 10(4 BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 10<S BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 15^ BMS13 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

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 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 CavityWaU 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 Backfiow Prevention in Over-Rim Water Supplies 100

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

[Continued from cover page iii] BMS29 Survey of Roofing Materials in the Northeastern States 10^ 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 10(4 BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 lOjS BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging lOjS BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions with

"Red Stripe" Lath Sponsored by The Weston Paper and Manufacturing Co 100 BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors, Sponsored by Palisade Homes lOji BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co 100 BMS39 Structural Properties of a WaU Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co 100 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 100 BMS42 Structural Properties of Wood-Frame Wall and Partition Constructions with "Celotex"

Insulating Boards Sponsored by The Celotex Corporation 100 BMS48 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 100 BMS44 Surface Treatment of Steel Prior to Painting 100 BMS45 Air Infiltration Through Windows 100 BMS46 Structural Properties of "Scot-Bilt" Prefabricated Sheet-Steel Constructions for Walls,

Floors, and Roofs Sponsored by The Globe-Wernicke Co 100 BMS47 Structural Properties of Prefabricated Wood-Frame Constructions for Walls, Partitions, and Floors Sponsored by American Houses, Inc 100 BMS48 Structural Properties of "Precision-Built" Frame Wall and Partition Constructions

Sponsored by the Homasote Co 100 BMS49 Metallic Roofing for Low-Cost House Construction 100 BMS50 Stability of Fiber Building Boards as Determined by Accelerated Aging 100 BMS51 Structural Properties of "Tilecrete Type A" Floor Construction Sponsored by the

Tilecrete Corporation 100 BMS52 Effect of Ceiling Insulation On Summer Comfort 100 BMS53 Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored by the Munlock Engineering Co 100 BMS54 Effect of Soot on the Rating of an Oil-Fired Heating Boiler 100 BMS55 Effects of Wetting and Drying on the Permeability of Masonry Walls. 100