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 15^ BMS7 Water Permeability of Masonry Walls 10^ BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10^ BMS9 Structural Properties of the Insulated Steel Construction Company's "Frameless-Steel" Constructions for Walls, Partitions, Floors, and Roofs 10)4 BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 10(i BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 10f5 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^ BMSl4 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 10^ BMSl7 Sound Insulation of Wall and Floor Constructions 10^ Supplement to BMS17, Soimd Insulation of Wall and Floor Constructions 50 BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation lOfi 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 10^ BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association 10^ BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 10^ BMS23 Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick

Manufacturers Association of New York, Inc 10^ BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile CavityWall Construction Sponsored by the Structural Clay Products Institute lOji BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions,

Floors, and Roofs 15^ BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction

Sponsored by the Nelson Cement Stone Co., Inc 10^ BMS27 Structural Properties of "Bender Steel Home" Wall Construction Sponsored by the Bender Body Co 10^ BMS28 Backflow Prevention in Over-Rim Water Supplies 10* 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 10j5 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co 15j5 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 ni]
UNITED S TAT ES DEPARTMENT OF COMMERCE • Jesse II. Jones, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

W STRUCTURES

REPORT BMS94

Water Permeability and Weathering Resistance of

Stucco-Faced, Gunite-Faced, and "Knap Concrete-Unit" Walls

l>y CYRUS C. FISHBURN

ISSUED DECEMBER 2, 1942

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 lO CENTS
Foreword

Previous Building Materials and Structures reports give the re- sults of investigations on the permeability of walls of masonry units

before and after exposure to the weather. This report deals with the

resistance to water penetration of higlily permeable masonry-unit

backings, faced with stucco or gunite, and with the permeability of walls built of "Knap concrete-units."

Lyman J. Briggs, Director.

In]
Water Permeability and Weathering Resistance of Stucco-Faced,

Gunite-Faced, and 'VKnap Concrete-Unit" Walls

by CYRUS C. FISHBURN

COWT

Page Foreword . ii I. Introduction 1 II. Wall specimens 2

1. Sponsors 2

2. Materials 3

(a) Masonry backing-units 3

(b) "Knap concrete-units" 3

(c) "Bondex" paint 3

(d) Mortar 3

(e) Stucco 3

Cf) Gunite 4

(g) Metal reinforcement for

gunite-faced walls 4

3. Construction of the walls 4

(a) Designation 4

(b) Stucco-faced walls 4

(c) Gunite-faced walls 5

(d) "Knap concrete-unit" walls 6

III. Testing of the walls 6

1. Water-permeability test 6

(a) Apparatus and method 6

fb) Observations 6

(c) Rating of performance 6

2. Outdoor exposure .-_ 7

ENTS

IV, Results of the tests 8

1. Permeability of stucco-faced walls 8

(a) Effect of temperature and

humidity during the curing

of stucco facings 8

(b) Effect of time interval be- tween application of the

scratch and finish coatS-. 10

(c) Effect of kind of stucco facing

and of kind of backing unit-- 10

2. Permeability of gunite-faced and

"Knap concrete-unit" walls 10

(a) Gunite faced walls 10

(b) "Knap concrete-unit" walls 10

3. Effects of outdoor exposure on structural soundness 10

(a) Stucco-taced walls 10

(b) Gunite-faced walls 11

(c) "Knap concrete-unit" walls 11

4. Effects of weathering exposure on

permeability 11 v. Summary and conclusions 20

ABSTRACT

The water permeabilities of small stucco- and gunite- faced walls and of walls built of "Knap concrete units" were measured before and after outdoor weathering.

Six kinds of stucco facings, 2 thicknesses of gunite

facings, and 7 kinds of units were represented in a group

of 26 walls.

All of the stucco- and gunite-faced walls were highly

resistant to water penetration. Periods of outdoor

exposure at Washington, D. C, varying from 16 to 49 months, had no important effect on permeability. The

resistance to penetration of walls built of "Knap concrete units" was excellent after the walls were painted.

I. INTRODUCTION

As part of an investigation on the water

permeability^ of small masonry wall specimens,

20 stucco-faced walls, 4 gimite-faced walls, and

2 walls built of "Knap concrete miits" were

tested before and after exposure to the weather.

The effects of the following variables on the

permeability of the walls are reported:

1. The kinds of backing and their moisture

content.

' Previous publications on the water permeability of masonry walls, which also contain data obtained from tests on 8 stucco-faced walls, are as

follows: Building Materials and Structures Reports BMS7, Water

Permeability of Masonry Walls; BMS41, Effects of Heating and cooling on the Permeability of Masonry Walls; BMS55, Effects of Wetting and Drying on the Permeability of Masonry Walls; and BMS70, Effects of Outdoor Exposure on the Water Permeability of Masoiuy Walls.

[1]
5ecfybn 3-0

Figure 1.Tij-pical stucco-faced wall with concrete block backing.

2. The relative proportions of portland cement

and hydrated lime in the stucco.

3. The admixture of asbestos fiber or pulverized limestone to the stucco.

4. The time interval between the application

of the scratch and finish coats of stucco.

5. The curing conditions given the stucco

facings.

6. The thickness and reinforcement of the

gunite facings.

The effects of weathering on the permeability

and structural soundness of the walls are also reported.

II. WALL SPECIMENS

The walls were about 40 in. long, 50 in. high,

and 9 in. thick. They were supported on steel channels and contained copper flashings so placed that water penetrating the exposed face was diverted at the bottom of the wall to the

back, where the leakage could be measured.

The ends and tops of backings built of masonry

units were sealed with a %-in.-thick mortar

parging before the facings were applied. A

typical stucco-faced wall with a backing of concrete units is illustrated in figure L

1. Sponsors

The stucco-faced walls were sponsored by

the Government agencies that collaborated

with the National Bureau of Standards in the tests. The walls were constructed at the

Bureau by experienced masons. The gunite-faced walls were sponsored by the

Cement Gun Co., Allentown, Pa., and were

built at the Bureau by their representatives.

The walls of "Knap concrete units" were

sponsored by Knap America, Inc. The units were cast in Los Angeles, Calif., and assembled

at the Bureau under the direction of the

sponsors.

[21
2. Materials

(a) Masonry Backing-Units

The masonry units are designated by small

letters and are briefly described. The pliysical

properties and the dimensions of the units used

in the backings for the stucco-faced walls are given in a previous report ^ of this series. Brick a were low absorptive units in a base

course for hollow unit backings of walls faced

with stucco (fig. 1). Brick c were dry-press units with a high rate

of absorption and were used in the backings of four stucco-faced walls. Their absorption, by

weight, during a 24-hr cold immersion was

about ] 5 percent.

Brick y were placed in the backings of two

gunite-faced walls. They were second-hand

(used) brick with rounded edges, and had an

absorption of 18 percent during a 24-hr cold

immersion.

Tile j were six-cell, 8- by 12- by 12-in. hardburned structural clay tile made at Magnolia,

Ohio, by the National F'ireproofing Co. They

were used in the backings of six stucco-faced

walls.

Tile V were three-cell, 4- by 12- by 12-in.,

hard-burned, partition tile, made by the National Fireproofing Co., and were used in the

backings of two gunite-faced walls. Block m were two-cell, 8- by 12- by 8-in., stone-concrete block and were used in the

backings of six stucco-faced walls. Block n were made of cinder concrete block,

and were used in the backings of four stucco- faced walls. Blocks m and n met the requirements of Federal Specification SS-C-621 for type 1, load-bearing units.

(6) "Knap Concrete-Units"

The two precast reinforced "Knap concrete- unit" walls were the same as those used in

similar walls built for structural tests.^ Descriptions of the units, their reinforcement, and

the accessories used with them are given in BMS40.

' Building Materials and Structures Report BMS82, Water Permeability of Walls Built of Masonry Units. (In BMS82 the bricks are designated by capital letters.)

s Building Materials and Structures Report BMS40, Structural Properties of a Wall Construction of "Knap Concrete Wall Units," sponsored by Knap America, Inc.

(c) "Bondex" I'anit "Bondex," a cernent-watci' piiiiil niiidc of about equal parts of white poilhiiid ci'iiiriit and hydrated lime, with n small amount of a stearate waterproofing iiigi'cdient, was applied

to the exposed faces of tiie "Knaj) concictcunit" walls. This paint, made in powder foi'm by the Reardon Co. of St. Louis, Mo., was

prepared by mixing with water.

{(I) Mortar

The proportions of the mortars, their uses, and the kinds of cementing materials are given

in table 1. Sieve analyses of the Potomac

River sands are given in table 2. The mortars were proportioned by weight and mixed in a batch mixer having a capacity of about 0.6 cu.

ft. The amount of water added to the mix was

adjusted to the satisfaction of the mason.

Table -F'rovortions and kinds of cementing materials used in the mortars

Mortar

2fc

3'' 4«

5/

Proportions of cement,

lime hydrate, and sand"

By volume By weight

1:1:6- _ 1:0.1:2

1:0:3.5 1:0:3—

1:0.42:5.1.

1:0.04:1.7.

1:0:3 1:0:3.7----

Kind of cement

Atlas Portland - .

.

Medusa Portland

Atlas Portland. -

.

Brixment-.

Kind of lime

Putty.' Do.'

" Proportioning was by weight, assuming that the Portland cement

weighed 94 Ib/cu ft, hydrated lime 40 Ib/cu ft. and that 1 cu. ft. of loose, damp sand contained 80 lb of dry sand. (Brixment masonry cement was assumed to weigh fi5 Ib/cu ft.)

* Used in backings for stucco-faced walls.

" Putty was made from Standard Lime and Stone Co.'s "Washington"

brand, powdered quicklime. (See table 5. BMS82.)

Used in backing, for gunite-faced walls.

« Used to caulk the joints between "Knap" units.

> Used to point the joints between "Knap" units. Table 2.

Sand sieve analyses

Identification of sand"

Weight passing U. S. Standard Sieve number

4 8 16 30 50 100

Sand A

%

100 %

10098 %93 %

70 %19 %2 Sand B 100 84 55 20 2

» Sand A was used in the stucco-faced and "Knap concrete unit" walls. Sand B was used in the gunite-faced walls.

(e) Stucco The letter designations, proportions, and

physical properties of the stuccos are given in table 3. Proportioning was by weight, and

the amount of water added to the mixtures was

13]
adjusted to the satisfaction of the mason. The

stuccos were mixed in the same mixer used for the mortars.

(J) Gnnite

Damp sand, containing about 6.6 percent of

moisture, and portland cement were proportioned by weight and placed in a stock pile for use in the cement gun. The weight proportions were 1 part of cement to about 4.25 parts

of dry sand. The volume proportions were 1 part of cement to 5 parts of loose damp sand.

{g) Metal Reinforcement jor Gunite-Faced Walls

The reinforcement used in the gunite facings

of two walls was galvanized, welded wire fabric, 2- by 2-in. mesh. The horizontal wires were No. 14 and the vertical ones No. 15 gage. Short lengths of No. 18 gage wire were used to anchor the mesh to the backings.

3. CONSTEUCTION OF THE WaLLS

(a) Designation

The walls were numbered consecutively as

built, and all except those built of the "Knap"

units, B241 and B242, are also identified by the

following additional letter designation : The first two letters identify the kind of stucco or gunite

facing. The next letter (in italics) represents

the kind of unit in the backing, and the final letter designates the time interval between application of the scratch and finish coats of stucco. For example, wall B69, built with a backing of brick c and a facing of SA stucco which was applied in two coats, "N" (1 day)

apart, is designated as wall B69-SAcN.

{h) Stucco-Faced Walls

The 8-in. walls for the stucco facings were

built with mortar 2 and either brick c, tile ,/ laid on end, or the concrete blocks m or ??. The in- terior portions of the vertical joints were not

filled with mortar, and the backings were of a highly permeable type of construction, workmanship B, described in BMS82. All of the

units were dry when laid. The backings were

aged and dried indoors for at least 2 weeks before the facings were applied.

The stucco-faced walls, listed in table 4, differed among themselves in the kind of backing

unit, the moisture content of the backing when

the stucco was applied, the kind of stucco facing,

the length of time between the application of the scratch and finish coats, or in the curing.

The stucco was applied with a plastering

trowel and rodded upward with a wooden

straightedge worked against vertical wooden

screeds at each end of the wall. Additional

stucco was applied after each rodding until a

thickness of about one-half in. was obtained.

When the sci'atch coat had stift'ened sufficiently,

it was floated with a wooden float and then

scratched. The scoring, Ke in. deep, was in long diagonal lines intersecting at intervals of 2

in. The time required to apply and rod the

scratch coat or to float and score it was about

10 min. The interval between rodding and

scoring, usually 2 or 3 hr, depended upon the

"suction" of the backing, which affected the

rate of stiffening of the stucco. The scratch coat applied to the dry brick backing of wall

B70 was scored 10 min after rodding, whereas

the stucco repeatedly dropped from the lower

third of the saturated brick backing of wall B71.

It required 3 hr of labor and the addition of a dry stucco mixture before the latter wall could

be rodded, and a second 3-hr period elapsed before the scratch coat was scored.

The finish coat was usuaUy applied 1 day

after application of the scratch coat (footnote

a, table 4). The scratch coats were wefl dampened before the application of the stucco for the

finish coats. The time interval between screeding and ffoating of the finish coat was usually

about 2 hr, the shortest interval being 24 min

for wall B70. The surface texture designated

as rough was obtained by use of a wooden float, a smooth texture by the use of a plastering

trowel.

The walls were cured, as described in table 4. Normal curing consisted in storing the waUs at room temperature and humidity and in wetting

them daily for 1 week after the apphcation of each coat of stucco. The other curing was by

storage in rooms with controlled temperature.

[4]
Table 3. -Proportions and physical properties of stucco mixtures Table 4. —Description and curin;/ of si iicco-faced ivalls

Designation symbol

SA

SBSOSD

SE

SF.

Proportions of port- land cement, hydrated lime, dry

sand, and admixtures, by weight "

1:0.1:3.0:0

1:0.2:3.6:0

1:0.4:4.9:0

1:0.1:3.6:0.3 -J. 1:0.1:3.6:0.03 « 1:0.1:3.0:0 .

Average water

content by

weight

of dry materials

Percent

20.5

20.9

21.6

19.8 29.6

20.5

A ver- age

initial flow >

Percent

135 11294

13290

135

Average 28-day compressive

strength «

Air- cured

Z6A7!.2 1,380

1,620

690

1, 120 540

1,380

Watercured

lblin.2 2,660

1,820

890 1,820

640 2,660

» The Portland cement met the physical requirements of Federal

Speriflcation SS-C-191a. The lime hydrate was contained in a putty made from the Standard Lime and Stone Co.'s "Washington" brand, powdered quiclclime.

i> Consistency was determined according to Federal Specification SS-ri58. Determined from 2-in. cubes, cured in air with the walls or in water

at 70° F. Pulverized limestone,

e Asbestos fibre.

' The finish coat contained dry pebbles, dashed against the troweled

surface.

(c) Gunite-Faced Walls

The gunite-faced walls are listed in table 5. The backings for the walls were built with

mortar 3, and they were of a similar construction to those used for stucco-faced walls. The

structural clay tile v were laid on end in the fu'st two courses and on the side in the upper two

courses. All joints in the brick backings and

the vertical joints in the tile backings were

raked to a depth of one-half in. to provide a key

for the gunite. The reinforcement in walls G2

and G4 w^as rigidly fixed at a distance of onefourth in. from the face of the backings. The

dry gunite mixture, previously described, was moved from the stock pile to the charging hopper of the cement gun, from which it was carried

by compressed an, through a hose, to the mixing nozzle. Water was added at the nozzle as the mixture was shot against the face of the

wall. When the gunite had been applied to a depth of about one-half in. the surface was

raked with the edge of a plastering trowel.

Immediately the second coat of gunite was

applied to a thickness of about one-eighth in. greater than the final thickness, and the excess was rodded with a wooden straightedge worked

against vertical grounds. The walls were cured

at room temperature and humidity ("normal"

curing given stucco-faced walls).

Wall

B94 B95

B70

B69 B72 B7L

B73. B74.

B76-

B77.

B78., B249

B273

B79. B80

B250

B274

B81.

B82. B83

Designation •

SAjN

SAjN SAcN

SAcN

SAcN SAcN SAjM

SAjN

SAjO

SAjP

SAmN

SAreN SAnN

SBmN

SCmN

SCnN

SC77N SDtbN

SErnN SFmN

Moisture

content of backing i>

Dry

do

do Medium dry... Medium wet... Saturated Dry ... do, do

do. Normal.

do-.

do.. do..

do..

do.-

do..

do.. do . do..

Curing of facings

Kind of curing "

Controlled

.

do ... do

do

do

do Normal

.

do.- do . do-.

.do

.do- .do-

.do.

.do.

.do.

.do.

.do.

.do.

.do.

Condition

of air in curing room

Percent «68

e 53

"^31

' 78

' 76

' 60

5452

38

42

42

6060

38

3660

60

33

31

31

Texture

of finish coat

Rough.

Do.

Do. Do.

Do. Do.

Do.

Do.

Do.

Do. Do.

Smooth. Rough.

Do.

Do. Smooth. Rough.

Do.

Do.

(«)

!> The first two letlcrs denote the Ifind of stucco used in the facing, the

letter in italic designat cs t hi' kind of masonry unit used in the baclving, and

the final letter denotes the lime interval elapsing between the completion

of the scratch coat and the application of the finish coat, as follows: M=3.4 hr; N=l day; 0 = 1 week; P=2 weeks.

^ The backings of all the walls were dried in warm air for several weeks

after their construction. Backings of normal moisture content were

wetted to the satisfaction of the mason before the scratch coat was applied. Walls B69, B72, and the saturated wall B71 contained abour 47,

94. and 135 lb of water, respectively, when the scratch coat was applied. The backings in walls marked "dry" were not wetted. The walls were cured for 1 week after the application of each coat of stucco. Walls given "controlled" curing were stored in rooms in which

the temperature was controlled. Walls given normal curing were stored indoors and wetted daily for 1 week.

d A rough surface was obtained with a wooden float; a smooth surface with a plastering trowel.

' The scratch coat was wetted only before the finish coat was applied. The finish coat was not wetted.

' Wetted daily, and covered with wet burlap draped a few inches from

the stucco facings.

e Wood floated and then garnishiMl with 15 lb of Potomac River gravel, thrown againsi ami i iiihedileil in tlie plastic surface. The gravel passed

a 5i-in. screen; minimum size was in.

Table 5.

Gunite-faced walls

Wall Designanation « Kind of backing Reinforcement in gunite

Nominal

thickness

of gunite

facing

in. Gl QVy

GRj/

QVv

GRi)

Brick y None 0. 75 G2 --.do steel fabric 1.00 G3 Tile V None ... 0. 75 G4 do steel fabric 1.00

"The first 2 letters denote the kind of gunite facing (either GP for plain, or GR for reinforced gunite), the last letter denotes the kind of unit used in the backing.

[•5]
(d) "Knap Concrete-Unit" Walls

The "Knap concrete-unit" walls were of a

construction similar to those built for the

structural tests described in BMS40. Holes in vertical ribs of the units matched those drilled

in vertical wooden splines, and steel spikes were

used as dowels to connect the splines and panels.

After assembling the units in the wall, the joints were caulked with mortar (mortar 4, table 1) and raked to a depth of one-half in. Two days

later the joints were pointed with mortar 5. The exposed face of wall B241 contained

four half-length units, 21% in. high, forming a

vertical- and a horizontal-joint intersection at the center of the wall. The back contained a standard unit of full length, 39 K in. long, which

rested upon a half-height unit of the same

length and was surmounted by another. In

wall B242 the assembly was reversed. The

exposed faces of both walls were given two

coats of "Bondex" paint applied after the first permeability tests had been completed.

in. TESTING OF THE WALLS

I. WATER-PERMEAniLITY TeST

The water-permeability test simulated heavy

wind-driven rain, but was of greater duration

than most natural wind and rain storms to which building walls are subjected. Ordinarily, information of a practical value on the

permeability of the specimens may be obtained

during 1-day exposures. However, for determination of the relative permeability of the

walls, or of possible slight changes in permeability resulting from weathering, the tests were sometimes continued for a maximum of

5 days. All of the walls were given a pre- liminary conditioning exposure of 2 days'

duration and then dried to nearly constant

weight before being tested for record.

(a) Apparatus and Method

The testing apparatus is illustrated and

described in BMS82. The walls formed one

side of a pressure chamber containing air maintained at a pressure of 10 Ib/ft^ above that

of the atmosphere. The face of the wall inside

the chamber, referred to as the exposed face, was covered with a film of water flowing at the

rate of 40 gal/hr. The relative humidity of the

air in the testing room was usually above 80

percent, and the temperature of the water

applied to the wall was maintained above the

dew point. The backs of the walls were whitewashed so that any discoloration produced by

the penetration of moisture could be easily

detected.

(b) Observations

Observations of the specimens were continual for the first several hours of each test, after which they were made at increasingly

longer intervals.

The following observations were made:

(1) Time required for the appearance of

moisture (dampness) on the backs of the walls,

above the flashings.

(2) Time required for the appearance of

visible water on the backs of the walls, above

the flashings.

(3) Time required for leakage to flow from

the flashings.

(4) Maximum rate of leakage, if any.

(5) Extent of damp area on the backs of the

walls, including that produced by the capillary

rise of moisture from water on the flashings.

The time of failure, when not exactly determined, was assumed to be the middle of the

interval between two inspections, and the uncertainty of the observation was assumed as plus or minus one-third of the interval between

the two inspections.

(c) Rating o/ Periormance

The arbitrary ratings of wall performance are based on the assumption that visible water,

extensive dampness on the back, or leakage

through the base of a wall, would damage

plaster where applied directly to the wall, or would injure the interior trim or furnishings of a

building. Since the exposure given the test walls was controUed to prevent condensation of

moisture on the backs, and since failure occurred

only through the penetration of moisture from

the exposed face of the specimens, no conclusions can be drawn from the tests regarding the effects of condensation in building walls similar to the

test specimens.

[6]
Wall performance ratings:

Excellent (E).—No water visible on l);ic]< of the

wall (above the flashings) at the o>n(l of I day.

Not more than 25 percent of the wall area damp

at the end of 5 days. No leaks * through the

wall in 5 days.

Good {G).—No water visible on back of the wall

at the end of 1 day. Less than 50 percent of the

wall area damp at the end of 1 day. No leaks * through the wall at the end of 1 day.

Fair (F).—Water visible on back of wall in more than 3 or less than 24 hr. Rate of leakage

through the wall less than 1 liter per hour at the

end of 1 day.

Poor (P).—Water visible on the back in 3 hr

or less. Rate of leakage less than 5 liters per

hour at the end of 1 day.

Very Poor (VP).—Rate of leakage through the

wall equal to or greater than. 5 liters per hour

at the end of 1 day.

2. Outdoor Exposure

The walls were exposed to the weather at Washington, D. C, for periods ranging from 16

to 49 months, within the interval February 1938

< Leaks are defined as follows; A leak is a flow of water from one or both

flashings, the total rate of flow being equal to or greater than O.OS liter per

hour.

to December 1941, inclusive, and Uiey were

tested for permeability both before and ;dl( i- being exposed.

The monthly iniixiniiuii and niininnini iii/- toimperatures and the monthly mean of dail\-

maximum and daily nunimum air t(!mj)(!ratures are shown in. figure 2, which also shows the

number of thawing cycles per month. Data

obtained from the Weather Bureau indicated

that the air temperature did not rise to above

freezing more than once in any one day. The

monthly precipitation for tlie period January

1938 to December 1941, inclusive, is given in table 6.

Table G.— -RJ unlhltj precipitation

Month 1938 1939 1940 1941 Nor- mal

in. in. in. in. in. January _ 2.6 3.4 2.

1

3.0 3.6 February. . ... . 2. 4 5. 7 2.8 0.9 3.3 March 2. 2 2.9 3.4 2.6 3.8 April 1.7 3.8 6.2 2.7 3.3 May 3. 5 0.4 3. 1 1.6 3.7 June 2. 3 4.6 0.9 4.4 4. 1 July 5. 1 2.0 5.7 5. 7 4.7

4.6 3.2 5.0 1.9 4.0 September 4.3 6.9 1.3 0. 5 3.2 October.- .. 1.2 4. 1 2. 1 1. 1 2.8 November 2.6 1.4 5.3 0.8 2.4 December. 2.7 2.2 2.3 3.9 3.3

Total 35.2 40.6 40.2 29.1 42.2

^

^ ^

^11

100

80

60

40

I

I

1 1 1 1 1 1 1 1 1 1 1 1 1

1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1

o

o

o

o o

o

o

•r—i'^aiimum monthly fempen3/ure \ ^/^ean ofdai/y max/mu/77 fempera/ure^

/ <r' \ X -A -^i>= \ \

—y^ ^ —*;—

\

-<>, \ Tv""

<r 1 . -v, ^s. \ ^ y/

P r ,-9— - ^

-jx. ^—L ' f -A —<^ ! Jl' :/

if f' p—

r ^ J

;<»—

/

\ Dk '°- \ -< —y^' /

— — —

—^ y / —\^ \ V.

?S_.-.;£t -> \^ -a. ^ /Minimum 'monM/yK of doi/y ^\\ p^y-

femperofure V' ' minimum femperafure V

1 ! 1 1 1 1 1 1 1 1

1 1 1 1 I 1 T 1 I 1 1 1 1 1 1 1 1 1 1 1 1 Jan

1938

Ju/y

1938

Jan. 1939Juiy

1939

Jan. /940Ju/y

1940

Jan.

1941

Ju/y /?ec. /94I 1941 Figure 2. —Temperature record.

48070:5—4 2- [7]
IV. RESULTS OF THE TESTS

1. Permeability of the Stucco-faced Walls

(a) Effect of Temperature and Humidity During

the Curing of Stucco Facings

The air temperature during the curing of the

walls listed in group I of table 7 was maintained

at 35°, 70°, or 95° F (table 4), but the relative

humidity was not controlled. Consequently in order to determine the effects of moisture conditions during curing, some of the specimens were protected from drying by daily wetting

and by draping with wet burlap, and others were neither wetted nor protected. The high

absorptive capacity of the brick in wall B70

accelerated the drying of the stucco, whereas

the water in the brick backings of walls B71

and B72 tended to keep the stucco damp.

Since all of the walls in group I, table 7, were

rated "excellent" in the permeability tests made

before the walls were stored outdoors, it is evident that the range in the conditions during

early curing had no significant effect on permeability. It should be noted, however, that the

drying to which the test walls were subjected

may not have been so rapid or so nearly complete as that to which exterior stucco-faced

walls built of similar materials and exposed to the sun and wind may be subjected.

Table 7.—Water permeability of walls

Wall Designation " Date placed

outdoors''

Duration of outdoor ex- posure

Time to fa

Damp

ilure as evid

Visible water

enced by ' ,

Leak

Maximum

rate of leakage per hourArea damp

in 1 day Rating

1 2 3 4 5 6 7 8 9 10

Stucco-faced walls, group I: Effect of cming temperatm-e

B94

B95

B70

B69 B72

B71

SAjN.

SAjN_

SAcN_

SAcNSAcN. SAcN.

{nov.'i938'

{nov.'i93"8-

{Aug'"l938.

{AugVigssV

{Xug^ 'l9'38.' {Xug.'lWsV

Months

0

310

310

32

0

32

0310

31

Hours

10±2

17±4

Hours

53±1

Hours Liters Percent

0

0

0

0

0

0

0

5

00

0

3

Stucco-faced walls, group II: Effect of time interval between application of scratch and finish coats

B73

B74

B76 B77

SAjM.

SA;N_,

SAjO..

SAjT_.

{Augri93S.

{AugVig'ss.

\Sept. 1938.

{sept."i938'

Months Ilotirs Hours Hours Liters Percent

0

0

0

0

00

0

0

a The first two letters denote the kind of stucco or gunite used in the facing. The third letter denotes the kind of masonry units used in the backing. For stucco-faced walls, the final letter gives the length of time interval between application of the scratch and finish coats, see note "a" of table 4.

•> The walls were tested for permeability before being placed outdoors and data from these tests are given in the first line for each respective wall

in the table. Data from the tests made after outdoor exposure are given in the second line unless otherwise noted.

0 The uncertainty of the observation is given if it exceeds 10 percent of the total elapsed time. A dash indicates no failure of the wall.

[8]
Table 7.—Water permeability of walls—Continiicd

Wall Designation » Date placed outdoors Duration of outdoor ex- posure

Time to failure as evidenced by « Maximum

rate of leakage per hour

Area damp

in 1 day Rating

Damp Visible water Leak

1 2 3 4 5 6 7 8 9 10

Stucco-faced walls, group III; Effect of kind of stucco facing

B78-.

I B249.

B273.

B79..

B80..

B250.

B274.

B81..

B82-. B83 -

SAmN.

SAreN_. SAnN..

SBraN_

SCtkN. SCmN__

SCmN_.

SDtoN. SEmN.

SFwiN..

{sept.'i938''

{Jan. 1946.'."

.Dec. 1939..

{sept."l938."

\Sept. 1938-

{j'an.'mo'.l

{Decri'939.-

{octVi938;i

Oct. 1938.

{octVi938^

Months

0

31

0

160

18

0310

31

0170

180

31

030

0

31

Hours Hours Hours Liters Percent

0

0

0

0

0

0

00

0

0

0

00

0

0

0

0

0

00

Gunite-faced walls

(') 0 0 E

m 0 0 E

0 0 E

0 0 E

0 0 E

0 0 E

0 0 E

Gl.

G2.

G3.

G4.

GPy.

GRy.

GPi).. GRu.

{Destroyed j.

{Feb."l938'.'.^'

iFeb. 1938-

{peb. 1938.

(<•) (d)

"Knap concrete-unit" walls

B241-

B242.

(e) Aug. 1939. W

.Aug. 1939-

0 0.7 39=h6 0 3 G

0 0 0 E

24 .2 .4 0.4 17 35 VP

0 .7 2.2 .7 1.1 10 P

0 0 0 E

24 . i . 1 .2 3.8 10 P

i Accidentally destroyed while stored outdoors.

« Painted with "Bondex" and again tested before being stored outdoor.^.

[9]
(6) Effect of Time Interval Between Application

of the Scratch and Finish Coats The intervals between the application of the

scratch and the finish coats of SA stucco to the

tile backings of the walls listed in group II, table 7, were 3.4 hi', 1 day, 1 week, and 2 weeks,

respectively, for walls B73, B74, B76, and B77.

The scratch coats on walls B76 and B77 were

wetted daily until the finish coat was applied.

The performances of all of the walls in the

permeability tests were rated "excellent," indicating that the differences in the time intervals

between application of the scratch and the

finish coats had no significant effect. However,

a more complete drying of the scratch coats,

such as may occur in exterior walls exposed for many days without wetting, might have af- fected the permeability of test walls B76 and

B77.

(c) Effect of Kind of Stucco Facing and oj Kind

off Backing Unit The walls listed in group III, table 7, differed

principally in the relative proportion of hydrated lime and cement in the facings or in the

use of admixtures such as powdered limestone- or asbestos fiber. All of these walls were rated

"excellent," and there were no significant dif- ferences noted in their performances.

Similarly, facings of SA stucco were equally

effective when applied to backing built of any

of the four kinds of masomy units, and facings

of SC stucco were likewise equally effective

when applied to backing of either stone or cinder concrete block.

Tests described in BMS82, and other tests,

were made on masonry walls built of like materials and in a like naanner to the specimens

used as backings for the stucco facings. The

tests showed that such walls were highly per- meable, had a high rate of leakage, and were

rated "very poor." The backings were not

tested before the facings were applied, but if they had been it is higlily probable that they

would likewise have been rated "very poor."

After completion, all of the stucco-faced walls were exceptionally resistant to water penetration and were rated "excellent." It is evident

5 Unpublished data on walls treated with cement-water paints and

other waterprooflngs.

that none of the variables in the kind of fac- ings or in their method of application, in the

kind of backings or in their moisture content, or in curing conditions given the facings had

an important effect on permeability of the

stucco-faced walls.

2. Permeability of Gunite-Faced and "Knap

Concrete-Unit" Walls

(a) Gunite-Faced Myalls

The four gunite-faced walls were highly re- sistant to water penetration and were rated

"excellent" regardless of the kind of backing

unit or type of facing (table 7).

{h) ''Knap Concrete-Unit" Walls

Before being painted with "Bondex," wall

B241, containing a vertical joint in the facing, was rated "good" and wall B242 was rated

"poor" (table 7). Moisture first appeared at or below the joints in the backings, and particularly at the bases of the wall above the

flashings. After they were painted, both walls were rated "excellent," indicating that the

treatment was effective.

3. Effects of Outdoor Exposure on

Structural Soundness

(a) Stucco-Faced Walls

When the stucco-faced walls were examined

after outdoor storage, the facmgs were found to be more or less cracked or crazed. Most of

them appeared to be warped slightly concave, and cracks were observed in the bed joints of some of the hollow-unit backings. These

cracks extended through the end pargings at the elevation of the bed joints, but did not

penetrate the stucco facings. Concavity in

the facings appeared to be incidental and was

not significantly affected by the kind of unit

in the backings or by the kind of stucco facing.

As no observations of the extent of crazing or warpage were made on the facings before the

walls were placed outdoors, it is not known

how much of their development resulted from

weathering.

The walls were dry when the width of the

cracks was measured with a 20-power Brinell

microscope. Many cracks, particularly those

[10]
running horizontally, appeared to be filled or partly filled with material deposited in tbem.

The maximum crack width, given in. table 8,

is the average width of t wo of the largest cracks

located within the area exposed to the permeability test. The wider cracks were found in facings applied to structural clay tile, and the

finer in walls backed with the brick c or with

cinder concrete block n. One crack, in the

top of wall B69-SAcN (fig. 3), may have been

caused by frost in the brick backing. Although

the units appeared to be in good condition,

damage due to the freezing of water in the upper

portions of walls built of the brick c has been

observed, and is described in BMS76. There was no spalling nor loose stucco on any of the

walls.

Table 8. — Width of cracks in the stucco facings, after storage outdoors.

Wall

B94.

B95.

B70.

B69.

B72.

B71.

B73.

B74. B76.

B77.

B78_ B249

B273

B79. B80

B250

B274

B81. B82.

Designation

SAjN_.

SAjN..

SAcN_

SAcN..

SAcN_. SAcN. SAjM.

SAjN_.

SAjO..

SAjP._

SAzreN. SA'nN_ SAnN_

SBraN. SCmN

SD7;iN SEmN

Maximum

width of cracks

In.

(-)

0. 007

. 008

b. 012

.003 .005

.010

.008

.009

.011

.004 .003

.003 .005

.008

.004

.005

a No cracks noted in the inner areas of the stucco facings, when dry. No cracks noted e.xcept at top of the wall, see figure 3. Width of crack about 0.04 in. when observed in spring of 1942.

After the walls had been tested for permeability, they were placed outdoors until April

1942, when the width of the cracks in some of

them was again measured . Little or no change was noted in the width of cracks in any except

wall B69, and the maximum width of cracks

in the top of this wall had increased from about

0.012 in. to 0.04 in.; the large increase in crack

width indicates a structural failure not common

to the other walls. The extent of crazing in some of the stucco

facings is indicated in figures 3 to 10, inclusive.

The walls had been wetted and then photographed while j)artly dry so llial iiioisliirc Id'l ii the cracks accentuated them. In genenil, t Ik i i' was less crazing noted in the facings of SA

stucco applied to l)ackiiigs of brick c ov of concrete block m and n than for the tile .7 (figs. 4, 5, and 6). The r(4ative propoiiions of hydrattid

lime and cement in facings apphcd to the l)h)ck

m had little efl"ect, although a slight increase in the size of cracks was noted with increase in the

proportion of lime (table 8 and figs. 6,7, and 8). The stucco facing containing asbestos fiber was

cracked, or crazed, to a greater extent than was that containing pulverized limestone (table

8 and figs. 9 and 10). Cracks in stucco facings

applied to hollow-unit backings were transverse

to the joints in the backings and usually intersected each other near the centers of the units, as in figures 5 and 7.

(b) Gunite-Faced Walls

The gunite-faced walls were accidentally

overturned while stored outdoors but, when

righted, only one of the four was found to be

damaged. No crazing was noted in the dry

gunitc facings resulting from 4 years of weathering exposure, and these walls appeared to have a higher resistance than did the stucco-faced

walls.

(c) "Knap Concrete-Unit" Walls

The motor joints in the facings of the

"Knap concrete-unit" walls were found to be

cracked when examined after 2 years of outdoor

storage. The largest of these cracks was about

0.008 in. wide. The walls were less rigid than

those faced with gunite or stucco, and it is probable that the cracks in the joints were opened or enlai'ged when the walls were trans- ported to and from the storage area.

4. Effects of Weathering Exposure on

Permeability

All of the stucco- and gunite-faced walls,

except B69, were rated "excellent" after ex- posure outdoors, and the weathering had little or no significant effect. Water entered a crack

in the top of wall B69 (fig. 3) and penetrated

the wall in about 10 In-. The back of the wall was 5-percent damp after 1 day, but was 40-

percent damp in 3 days so that it was rated

"good" instead of "excellent."

[11]
Figure 3.—Wall B69 SACN after weathering. The wall was wetted daily and cured in damp'air at a temperature of 37° F for 1 week. The jagged lines~at top' of the wall indicate the extent

of cracking observed on the dry wall. The width of cracks measured at b, d, and i (indicated by transverse lines) was about 0.012 in.

[12]
[13]
Figure 5. — Wall B74 S^AjA' afler wealhcring. The structural clay tile backing is indicated in dashed lines. The width of cracks at 6, e,j, n, and r (indicated by transverse lines) was about 0.008

in. Extensive crazing was noted on the dry wall.

[14]
[IS]
[16]
i

i

i i

I—

l iGURE 8. —Wall B80 SCmX uflcr uralliu niy.

Extensive crazing was observed in the dry wall. The width of cracks at 6, d, 1, and n (indicated by transverse lines) was about O.UOS in.

[17]
Fiui RK y.-- Il'a// BSl SDniA' after waitlwrntg. No cracks were noted on the dry wall.

[18]
Figure 10.—Wall B82 SEmN after weathering. The width of cracks at g, e, and / (indicated by transverse lines) was about 0.008 in. Extensive crazing was noted on the dry wall.

[19]
Tests of eight stucco-faced walls reported in BMS76 indicated a significant but not a serious

increase in permeability after a period of out- door exposure. Before exposure, five of eight

walls were rated "excellent" and three "good."

After weathering exposuzTS lasting 2 or 3 years, one wall was rated "excellent," five "good,"

one "fair," and one "poor."

The two painted "Kjiap concrete-unit" walls

which were rated "excellent" in tests prior to 2 years of outdoor storage, when tested after weathering, were rated "poor" and "very poor"

(table 7). Wall B241, containing a vertical

joint in the facing, leaked excessively, although

it is probable that the joints in both walls were damaged during removal to and from the storage

yard. Even so, repainting of the joints would

have effectively sealed them so that the walls

would again show a high resistance to water

penetration.

V. SUMMARY AND CONCLUSIONS

Twenty stucco-faced, four gunite-faced, and

two walls built of "Knap concrete units" were

tested for water permeability before and after exposure to the weather. The backings of the

stucco-faced walls varied in their moisture content and in the kinds of masonry unit; the fac- ings varied in the relative proportion of portland

cement and hydrated lime, the time intervals

between application of the scratch and finish coats, and in the curing. The gunite-faced

walls differed in the thickness and reinforcement

of the facings and in the kind of backings.

There were no construction joints in the facings

of any of the specimens, except in those built

of "Knap concrete units." Since the specimens were small, and there were no adjacent struc- tural members, the weathering exposure did not

simulate all the conditions wMch may produce

structural cracks in a large wall. The following conclusions were derived re- garding the permeability and structural soundness of the walls:

1 . The stucco- and gunite-faced walls were

very highly resistant to water penetration when

first constructed.

2. Periods of outdoor exposure ranging from

17 to 32 months, at Washington, D. C, resulted

in the formation of cracks, or of craziftg, in most

of the stucco facings, but there was no loose or

spalled stucco on any of the walls. There was

little or no significant or important effect on the

permeability of the walls produced by the

weathering.

3. The gunite facings were not crazed by 4

years of weathering, nor was their permeability

significantly affected.

4. Before they were painted with "Bondex,"

the "Knap concrete-unit" walls were more

permeable than either the stucco-or gunitefaced walls. Immediately after painting, their

resistances were comparable to that of other

walls. Washington, September 5, 1942.

[20]
BMS33

BMS34

BMS35

BMS36

BMS37

BMS38

BMS39

BMS40

BMS41

BMS42

BMS43

BMS44

BMS45

BMS46

BMS47

BMS48

BMS49

BMS50

BMS51

BMS52

BMS53

BMS54

BMS55

BMS56

BMS57

BMS58

BMS59

BMS60

BMS61

BMS62

BMS63

BMS64

BMS65

BMS66

BMS67

BMS68

BMS69

BMS70

BMS71

BMS72

BMS73

BMS74

BMS75

BMS76

BMS77

BMS78

BMS79

BMS80

BMS81

BMS82

BMS83

BMS84

BMS85

BUILDING MATERIALS AND STRUCTURES REPORTS

[Continued from cover page ii]

Plastic Calking Materials lOfS Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 10^

Stability of Sheathing Papers as Determined by Accelerated Aging 10^

Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions with

"Red Stripe" Lath Sponsored by The Weston Paper and Manufacturing Co 10j5 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors, Sponsored by Palisade Homes 10^

Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co 10^

Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co 10^

Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored

by Knap America, Inc 10^

Effect of Heating and Cooling on the Permeability of Masonry Walls 10^

Structural Properties of Wood-Frame Wall and Partition Constructions with "Celotex"

Insulating Boards Sponsored by The Celotex Corporation 15^ Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 10^ Surface Treatment of Steel Prior to Painting 10^ Air Infiltration Through Windows 10^ Structural Properties of "Scot-Bilt" Prefabricated Sheet-Steel Constructions for WaUs,

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

Structural Properties of "Precision-Built" Frame Wall and Partition Constructions

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

Structural Properties of "Tilecrete Type A" Floor Construction Sponsored by the

Tilecrete Co 10^

Effect of Ceiling Insulation Upon Summer Comfort 10^

Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored by the Munlock Engineering Co 10(4 Effect of Soot on the Rating of an Oil-Fired Heating Boiler 10^

Effects of Wetting and Drying on the Permeability of Masonry Walls lOfi A Survey of Humidities in Residences 10^ Roofing in the United States—Results of a Questionnaire 100 Strength of Soft-Soldered Joints in Copper Tubing 10^

Properties of Adhesives for Floor Coverings 10^ Strength, Absorption, and Resistance to Laboratory Freezing and Thawing of Building

Bricks Produced in the United States 15f5 Structural Properties of Two Nonreinforced Monolithic Concrete Wall Constructions 100 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by the Portland Cement Association 100 Moisture Condensation in Building Walls 100

Solar Heating of Various Surfaces 100 Methods of Estimating Loads in Plumbing Systems 100 Plumbing Manual 200

Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by Herman A. Mugler 150 Performance Test for Floor Coverings for Use in Low-Cost Housing: Part 3 150

Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 100 Asphalt-Prepared Roll Roofings and Shingles 150 Fire Tests of Wood- and Metal-Framed Partitions 200

Structural Properties of "Precision-Built, Jr." Prefabricated Wood-Frame Wall Construction Sponsored by the Homasote Co 100 Indentation Characteristics of Floor Coverings 100

Structural and Heat-Transfer Properties of "U. S. S. Panelbilt" Prefabricated SheetSteel Constructions for Walls, Partitions, and Roofs Sponsored by the Tennessee

Coal, Iron & Railroad Co 150 Survey of Roofing Materials in the North Central States 150

Effect of Outdoor Exposure on the Water Permeability of Masonry Walls 150

Properties and Performance of Fiber Tile Boards 100

Structural, Heat-Transfer, and Water-Permeability Properties of Five Earth-Wall

Constructions 200 Water-Distributing Systems for Buildings 150 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 4 150

Field Inspectors' Check List for Building Construction (cloth cover, 5 x 7^ inches) 200 Water Permeability of Walls Built of Masonry Units 200 Strength of Sleeve Joints in Copper Tubing Made With Various Lead-Base Solders 100 Survey of Roofing Materials in the South Central States --_ 150 Dimensional Changes of Floor Coverings with Changes of Relative Humidity and

Temperature 100

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

[Continued from cover page iii] BMS86 Structural, Heat-Transfer, and Water-Permeability Properties of "Speedbrik"" Wall

Construction Sponsored by the General Shale Products Corporation 15j5 BMS87 A Method for Developing Specifications for Building Construction—Report of Subcommittee on Specifications of the Central Housing Committee on Research, Design and

Construction 10^ BMS88 Recommended Building Code Requirements for New Dwelling Construction With

Special Reference to War Housing 10^ BMS89 Structural Properties of "Precision-Built, Jr." (Second Construction) Prefabricated

Wood-Frame Wall Construction Sponsored by the Homasote Co 15^ BMS90 Structural Properties of "PHC" Prefabricated Wood-Frame Constructions for Walls,

Floors, and Roofs Sponsored by the PHC Housing Corporation 15#

BMS91 A Glossary of Housing Terms 15^ BMS92 Fire-Resistance Classifications of Building Constructions 25f

BMS93 Accumulation of Moisture in Walls of Frame Construction During Winter Exposure 10f5 BMS94 Water Permeability and Weathering Resistance of Stucco-Faced, Gunite-Faced, and

"Knap Concrete-Unit" Walls 10^