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

Hugh L. Dryden, Chairman. Howard P. Vermilya, Vice Chairman.

National Bureau of Standards. Federal Housing Administration.

Vincent B. Phelan, Secretary.

Mary F. Taylor : Assistant Secretaries : Louise D. Card

TiRRELL J. FeRRENZ,

Federal Home Loan Bank Board.

A. C. Shire,

United States Housing Authority.

Warren G. Noll,

Public Buildings Administration.

Luther M. Leisenring,

Construction Division (War).

Edward A. Poynton,

Office of Indian Affairs.

John F. Donovan,

Farm Security Administration.

George W. Trayer,

Forest Service (F. P. Laboratory).

RoLLO H. Britten,

Public 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 COMMERC^E • Jesse H. Jones, Secretary

I NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs. Director

BUILDING MAT E R I ALS ; . B

and STRUCTURES \ i REPORT BMS82

Water Permeability of Walls

Built ot Masonry Units

by CYRUS C. FISHBURN

ISSUED APRIL 15, 1942

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 ot reports are to be construed accordingly.

UNITED

FOR SALE

STATES GOVERNMENT PRINTING OFFICE • WASHINGTON

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

1942

20 CENTS
Foreword

Exterior masoniy walls of houses or other buildine;s may occasionally be penetrated by wind-driven rains, with subsequent damage to the interior finish of such structures. An extensive investigation in

the water-permeability of small masonry wall specimens has resulted

in the publication of reports on the permeability of masonry walls

when first constructed, after being exposed outdoors, and after being

subjected in the laboratory to altei-nate wetting and drying and in the

dry condition to extremes of temperature. This is a report on the

water permeability of walls built of masonry units.

Lyman J. Briggs, Director.

In]
Water Permeability of Walls Built of Masonry Units

by CYRUS C. FISHBTRN

CONTENTS

Page

Foreword ii

I. Introduction 1

II. Wall specimens 1

1. Sponsors 3

2. Materials 3

(a) Bricks - 3

(b) Structural clay tiles 6

(c) Concrete units 8

(d) Mortars , 12

(e) Grout 12

(f) Metal ties 12

3. Construction of the walls 13

(a) Procedure 13

(b) Designation of specimens 13

(c) Kinds of workmanship 13

(d) Construction of sponsored walls

built of special units 19

III. Testing of the walls 22

1. Apparatus and test method 22

2. Observations 23

3. Method of rating performance 24

ABSTRACT

The water permeabilities of small masonry wall specimens were measured. Fourteen kinds of workmanship, 39 kinds of units, and 10 kinds of mortars were

represented in a group of 140 walls. The permeability of the specimens was low when the

vertical joints were filled or partly filled with mortar or

grout, when the suction of the bricks was low, and

when a mortar having a high water retentivity was

used. The effect of water retentivity of the mortars on the permeability of the walls was greatest when the

brick-suction was high. Mortar having a low water

retentivity stiffened rapidly when placed in contact with dry, highly absorptive bricks, and units having a low suction floated out of alinement when placed in contact with such a mortar.

I. INTRODUCTION

The results obtained from a study of the

water-permeability of masonry walls have been

described in a publication ^ of the National

Bureau of Standards. In that investigation the

1 Building Materials and Structures Report BMS7, Water Permeability of Masonry Walls.

Page

IV. Data and discussion 25

1. Data 25

2. Effect of workmanship on permeability 30

(a) Brick walls 31

(b) Brick-faced walls backed with hollow units 32

(c) Cavity walls 32

3. Effect of brick-suction on permeability 33

4. Effect of water retentivity of the mortars on ease of construction and on permeability 33

5. Effect of properties of unit on per- meabillity 34

(a) Absorptive properties of the

bricks 34

(b) Cored holes in bricks 35

(c) Brick of special shapes 35

(d) Structural clay tile or concrete

units 36

V. Summary 37

permeabilities of stucco-faced walls and of walls

built of masonry units were measured, and the

effectiveness of waterproofing treatments applied to leaky brick walls was determined.

This report describes the results obtained

from tests on a second group of walls built of masonry units. It reports the effects of differ- ent methods of construction, the effects of the

absorptive capacity of the bricks at time of laying, and the effects of the water-retaining

capacity of the mortars on the water permeability and on the ease of construction of those

walls. For convenience, complementary data

and information published in BAIS7 are in- cluded in this report, which therefore contains

all of the information on the permeability of

walls built of masonry imits that was obtained

in both investigations (except for that on waterproofings)

II. WALL SPECIMENS

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

and 6, 8. 9, 10, or 12 in. thick, depending upon

[1]
5ecfion on B-B

Morfarparging on^ ends and fop ofyra/f-

\-.^^ H 40 "ctpprox.

I

3

I

I

^ ^ ^

Bed

1

B

3=^ ^ ^^^^^^ ^3

I

/I

Rear Eki^f/on

"otand.Cfjaf7ns/—^

Section on "A-^'

Figure 1.Brick masonry wall specimen.

8-inch wall laid in common American bond.

the size of the units, the number of wythes, and

the type of construction. The rear elevation

and two cross sections of a typical brick

masonry test wall are shown in figure 1. The

walls, which were built at the Bureau by experienced masons, were supported on steel channels to facilitate handling, and contained one or more copper flashings so placed as to collect any

leakage passing through them or dropping

between the wythes. They were faced at the

ends and top with a moitar pai'ging % to % in. thick, sealing these areas, so that a pressure

gradient from the face to the back of the walls was maintained within the masonry when an air pressure was applied to one face. Fourteen different workmanships or methods

of construction, 22 kinds of bricks, 17 kinds of structural clay tiles or concrete units, and 10

[2]
mortars were represented in tlie group of 14U

wall specimens.

1. Sponsors

The testing of the walls and the constniction

of 98 specimens were sponsored by the Go\ ern- mental agencies that collaborated -with the

Bureau in the investigation.

Other sponsors furnished the labor and materials for, and supervised the construction of, 42

other walls. These sponsors were: The Brick Manufacturers Association of New York, Inc., one brick cavity wall. The W. E. Dunn Manufacturing Co., Holland, Mich., one wall of "Dun-ti-stone" concrete units, and four walls of "Dunstone"

concrete units.

The General Shale Products Corporation,

Johnson City, Tenn. (with the Structural Clay

Products Institute and the Speedbrik Corporation, both of Washington, D. C, and the

Pursell Co., of Cincinnati, Ohio, as collaborators), nine walls of "Speedbrik."

The Munlock Engineering Co., Washington,

D. C, eight walls of "Munlock" brick.

The National Concrete Masonry Association,

Chicago, 111., one cavity wall of "Malilstedt"

concrete block.

The National Fireproofing Co., Pittsburgh,

Pa., three walls of "Dri-Speedwall" tile. The Puddington Sales Corporation, New

York, N. Y., three walls containing "TightWall" brick.

W. H. Spaulding, architect of Long Island,

N. Y., four walls containing bricks of his design.

The Structural Clay Products Institute of Washington, D. C, three brick-tile cavity

walls and one grouted brick wall containing

steel reinforcement. The Institute also fur- nished bricks for the construction of eight walls

built and tested to determine the effects of coring brick on permeability.

The Whitacre-Greer Fireproofing Co.,

Waynesburg, Ohio, four walls of H-brick.

2. Materials

All of the materials were representative of

those used in building construction. They

were either furnished by the sponsors or puiciiased from the makers or from buildingsupply dealers.

(a) Bricks

The 22 kinds of bri(;ks included many units

that were hollow or cored; some of the special

shapes were designated as bricks by the sponsors even though their net areas were less than 70

percent of their gross cored section. Three

kinds of solid bj'icks, designated as brick A,

B, and C, were selected for their absorptive

properties and were used in more than half of the wall specimens. The physical properties

of all of the bricks are given in table 1. The

dimensions of bricks of special shapes are shown

in figure 2 and the photographs are shown in figure 3. The chaTacteristics of the several bricks and

their use are listed below:

Brick A. —Red, side-cut, shale, low-absorptive. Made in Martinsburg, W. Va., and

typical of shale bricks from the North Central

States. Purchased from the United Clay

Products Co., Washington, D. C. Used in 15

walls and in walls built for structural tests.

Brick B:—Red, side-cut, surface-clay, mediumabsorptive. Made in Baltimore, Md. "Lombardy Colonial" brand of the Hydraulic Press Brick Co., Washington, D. C, used in 44 walls. Brick C.—Red, dry-press, clay, high-absorptive. Made in Alexandria, Va., and sold by

the Hydraulic Press Brick Co. Used in 29

walls. Brick D.—Dark - red, soft - mud, sanded.

About 25 percent contained frogs with the

raised letters "Homewood." Made in Baltimore, Md., by the Baltimore Brick Co. Purchased from the Hydraulic Press Brick Co.

Used in two walls and also in walls for structural tests; see BMS5.

Brick E.—Hed, side-cut, surface clay. Very

similar to Brick B. Made in Baltimore, Md.,

by the Baltimore Brick Co. Used in two walls

sponsored by the Structural Clay Products

Institute, Washington, D. C, and also in similar walls built for structural tests.

2 Building Materials and Structures Report BMS5, Structural Properties of Six Masonry Wall Constructions.

3 Building Materials and Structures Report BMS2(. Structural Properties of a Reinforced Brick Wall Construction and a Brick-Tile Cavity- Wall Construction Sponsored by the Structural Clay Products Institute.

[3]
Brick F.—Red, soft-mud, sanded. Contains

frogs having the raised letters "SSBCO." Made

in Coeymans, N. Y., by the Sutton and Sudderly

Brick Co. Used in one wall sponsored by the

Brick Manufacturers Association of New York,

Inc., and also in similar walls built for structural

tests.

^ Bricks G, H, J, and K.—Furnished by the

Structural Clay Products Institute. Used in eight walls for the determination of the effects of cores in brick on permeability. Bricks G and

H were cream, side-cut, fire-clay units made in Canton, Ohio, by the Belden Brick Co. Brick

6f were solid; brick had 21 cored holes 0.56 in. in diameter. Bricks J and K were gray, sidecut, clay units with textured face and ends,

made at Perla, Ark., by the Acme Brick Co.

Brick J were solid; brick K contained three

cored holes 1)^ in. in diameter.

Brick L.—Red, side-cut, shale, with textured

ends and face and with three l}^-in. diameter

cored holes; made at Redfield, Iowa, by the

Redfield Brick and Tile Co. Used in two

< Building Materials and Structures Eeport BMS23, Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick Manufacturers Association of New York, Inc.

cavity walls sponsored by the Structural Clay

Products Institute.

Brick M.—Red, end-cut, shale unit of special

shape containing five horizontal cored holes

about 1 in. in diameter. Trade name, "Munlock Dry Wall Brick." Made at Winchester,

Va., by the Colonial Brick Co. Used in eight

walls sponsored by the Munlock Engineering

Co., Washington, D. C, and also in walls for structural tests.

Brick N.—Yellowish-pink, side-cut, fire-clay

brick of H-shape. Heavy vertical scores on one

edge and light vertical scores at the four ends.

Contained six %-in. diameter vertical cored

holes. Used in four walls sponsored by the

Wliitacre-Greer Fireproofing Co., Waynesburg,

Ohio.

Bricks 0 and P.—Red, side-cut, shale, hoi-' low, of special shapes and of various sizes. Trade name, "Speedbrik." Used in nine walls

sponsored by the General Shale Products Co.,

Johnson City, Tenn. Brick 0 was made at Kingsport, Tenn.; brick P was made by the

' Building Materials and Structures Report BMS53, Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored by the Munlock Engineering Co.

Table 1.Physical properties of the bricks

Designation

Average dimensions » Average

dry

weight

Absorption by total immersion Saturation

ooefBcient, C/B

Absorption b by

partial immersion, flat,

1 minute T W L

5-hr cold

24-hr

cold, C

5-hr

boil, B

in. in. in. lb % % % g A 3.8 8.

1

2.3 5.8 1.6 1.9 3.5 0. 53 10 B' 3.8 8.

1

2.3 5.0 8.7 9.4 13.4 .70 33 3.9 8.

1

2.3 5.0 14.2 14.6 16.9 .86 112 D 3.7 8.0 2.2 4.5 10.2 11.3 15.1 .74 25 E 3.8 8.0 2.3 4,8 9.5 10.2 14.7 .69 38 F 3.7 8.1 2.3 4.

1

13.4 13.8 18.7 .74 42 0 3.7 8.1 2.2 5.4 5.

1

5.4 7.8 .69 12 H 3.7 8.

1

2.2 4.

1

2.9 3.3 6.0 .54 6 J. 3.9 8.2 2.3 4.9 8.5 9.3 13.5 .68 31 K 3.7 8.0 2.2 4.2 6.0 6.8 13.4 .54 27 i 3.8 8.0 2.2 4.6 2.6 3. 5 7.6 .44 9 M 8.0 2.2 7.9 9.5 1.6 1.6 1.9 .73 3 N 7.9 8.

1

2.3 7.3 7.2 7.4 8.5 .87 16 0 7.9 12.0 2.8 12. 3 3.6 6.6 .55 20 P 7.9 11.9 2.7 12. 9 1.5 2.8 .51 6

/fi 3.7 (') 2.2 4.0 3.5 4.2 6.5 .64 7 3.7 7.9 2.2 4.4 1.3 2.

1

4. 7 .45 3 Rz- 3.8 (') 2.2 4.4 4.3 4.9 6.6 .73 5 U 3.7 8.1 2.2 6. 1 4.8 5.3 9.3 .56 30 V 3.7 8.1 2.2 4. 31 8. 18 8.98 15. 07 .59 32 W. 3.3 7.9 2.2 3. 93 3. 00 4.02 9.82 .38 4 X 3.7 8.0 2.2 4. 39 8. 22 9. 11 15. 83 .57 35

Time required for total penetration by capil- lary action

Flat Edge End

5.2

0.8

. 1 1.0 0.7

.6

1.5 4.8

0.1

. 1

. 1 1.4 0.8

hr

30. 0 7.9

0.3 2.0

6.0

1.4 8.6

50.0

2.6

2.8

118.0

70.0

38

161.0

8 41.0

3 24.0

2 1.2

15 10.6

3 1.2

Modulus of rupture

gross area

hr

'23.0

1. 7

11. 0 23.0

6.5 26.2

18.6 47.0

75.0

Ib/in.-

2, 270

820

250

550 830

540

1, 660

900

1,040

1,240

1,720

550

1,360

1, 690

910 830

746

1, 319

» 7"= wall thickness, as laid. X=length parallel to cores, or height in course for solid units.

'> Based on an equivalent area of 30 sq in.

' Average values for 2 shipments in same kind of unit.

<! Over 6.500 lb/in.

«

e Face, 7.60 in.; back, 7.92 in.

' Face, 7.92 in.; back, 8.09 in.

[4]
"-^ '7- .-

I2f6-

,

1

— 12s

5P£EDB/f/n - sfrefcher a/7/As

^dia. Holes

/is

—\

3^0i_

"h "brich (N)

ffJi'a.Hole

Scon'ngjzdp.

kdiaMes

I

i

MUNLOCK BBICH (M) TIGHT- WALL BRICK (R)

Figure 2.

Details of bricks of special shapes.

SPAULDIN6 BRICK {^)

Claycraft Co., Columbus, Ohio. The physical

properties of a 6- by 12- by 2.7-in. unit also made in Kingsport, Tenn., and used in three

walls, were similar to those of the 8-inch brick 0

hsted in table 1. Bricks Ri, R2, R3, and t/.—Used in three

walls sponsored by the Puddington Sales Corporation, New York, N. Y. Bricks Ri, R2, and

R3 were side-cut, fire-clay units. The stretcher

brick had recessed ends and the header brick were recessed on the sides. Trade name,

"Tight-Wall Brick." Brick Ri was cream-colored, contained sLx %-in. diameter and four %-m.

diameter cored holes, and was made at East

Sparta, Ohio, by the U. S. Quarry Tile Co.

Bricks R2 and R^ were respectively gray and

[5
t • •

• « * mw

9 # #

« • •

* • « 0*0

0 0 0

0r/c/rs 6,H,J,/< (-oored dr/ck wa//s)

Spaa/cf/ng dr/c/rj(bricks Var?a'l^)

;r —

;r —» w w « «

M 1 ri» m • * - --

%m.m, m m m

.i • e at •

• * *

• «|

Speed8r/k (l?nck5 O andP)

< V -,1 J :

"H"br/ck(N)

» t I •

Mun/ock brick (M) Tighf-iya// bricks (/^)

Figure 3.

Bricks of special shapes.

salmoii-piiik in color and each contained two

cored holes l^ie in. in diameter and one cored

hole 1 in. in diameter. They were made at Midvale, Ohio, by the Evans Brick Co. Brick

U were red side-cut, clay, common brick, used

as backup for the walls. They wei-e made at Bladensburg, Md., by the United Clay Products

Co.

Bricks V, W, and X.—Used in four walls

sponsored by W. H. Spauldmg, Long Island,

N. Y. Bricks V and W were red, soft-mud,

sand-struck, with recessed ends. Headers were

also of special shape. Brick V was made at New Oxford, Pa., by the AUwine Brick Co.

Brick W was made at the Glenliead, LongIsland, N. Y., plant of the Post Brick Co.

Brick were red, soft-mud, sand-struck, regularly shaped units. They were made by the

AUwine Co. at New Oxford, and were used for backup. The absorptive properties of bricks A" and V were similar.

(6) Structural clay tiles The structin-al clay tiles were used principally

as backing units. Their physical properties are given in table 2; detailed measurements and

photographs are shown in figures 4, 5, and 6. The tiles were designated by lower-case letters, and their characteristics and use are listed below:

Tile d.—Double-shell, hard. Stretchers were

6-cell, end-bearing. Bonding units were 4-cell,

[6]
side-bearing. Used as backing units m two

walls.

Tile e. —Side-construction, stretchers were 3-

cell and bonding units were 4-cell. Used as backing units in tkree walls.

Tile f. —Speed-a-backer, hard, side-bearing.

Used as backing unit in two walls. Tile g. —Raritile, end-bearing. Both the

stretcher and the bonding units were 4-cell. Used as backing units in two walls.

Tile j.^ Standard tile, end- oi- side-bearing.

Used ill two walls without lacings, as a backing

unit in one wall, and in walls (without facings)

for structural tests; see BMS5.

Tile k.—Double-shell, soft. Stretchers were

6-cell, end-bearing. Bonding units were 3-cell, side-bearing. Used as backhig units in five walls.

Tile I. —Speed-a-backer, soft, side-bearing.

Used as backing units in six walls.

Table 2.

Physical properties of structural clay tile

[Properties of the stretcher units are given in the first line, those of bonding units, if any, are given in the second line]

Designation

Exterior dimensions Thickness

of face

shell

Dry

weight

Absorption by

24-hr cold immersion, C

Absorption by

1-hr

boil, B

oattuation

coeffi- cient C/B

w eignt per square

foot of wall area

Compressive

strength Face shell immersed in 'A in. of %vater

T W L

Net

area Grossarea

Absorption, 3 minutes

Capillary

rise in

first hour

Time required

for capillary rise through unit

in. in. in. in. lb % % lb Ib/in.^ Iblin:' g/cm 2 in. in. hr

t 8.2 12. 2 10. 6 0.71 34. 7 10. 0 12.5 0.80 38.4 6, 280 2, 650 0. 10 1.8 8. 2 84 d

\ 8.0 5.0 11.9 .62 14. 6 5. 1 7.6 .67 35.7 3, 290 1.520 .01 1. 2 7.5 1.54

f 7.9 5.0 12.0 . 61 17. 3 4. 2 6. 1 .67 41.7 7, 290 2, 070 .02 2.3 4. 7 168

e.. . _ \ 3.8 5.0 12. 0 .52 10. 1 4.3 5.8 . 72 23. 3 6,910 2, 490 .02 1.7 3. 1 116 / — 7.6 7.6 11. 8 . 66 22, 1 1. 2 3.2 .37 35.8 2, 830 730 .01 2.0 2. 6 168

r 8.0 12.7.8 1. 16 27.8 10.4 14.0 . 74 42.7 4, 780 2, 520 . 16 3.0 8.0 11 g

I 7.9 12.0 7.8 1. 12 20. 7 7. 2 U. 1 .64 25.8 5, 390 2, 820 .08 1.9 7.9 29

i 8.0 12. 1 12. 1 0. 70 35.4 3.9 5.6 .67 .34.8 C) (") .025 1.4 4.8 167

f 7.9 12.3 9.8 1.04 32.7 12. I 15.7 .77 39.3 4, 950 2, 590 .04 1.6 7.9 59

it \ 8.

5.3 12. 3 1.00 16.9 17.7 21. 2 .84 .37.7 . 17 2.0 8.2 29

I 7.9 7.8 12.0 0.81 22.3 18. 4 19. 5 .95 34. 5 3. 370 1. 150 .35 2.7 7.9 18

p

f 8.0 12. 1 7.6 1.49 26. 6 11. 4 14. 7 .77 42.0 4, 690 2,500 . 14 2.2 8.0 12 \ 7.8 11.8 7.5 1. 44 20.9 4.8 7.9 .60 34.0 4. 360 2, 330 .03 1.7 6.3 128

8 3.5 5.0 11.8 0. 99 10. 4 1.5 2.4 .64 25.7 11, 680 3. 380 .01 1.8 1.9 168

Sl 8.0 7. 7 16. 1 . 57 37. 5 2.0 2.3 .86 43. 3 9,390 2, 450 .01 1. 2 1.5 168

S2 . 8.0 5.0 11.9 .56 18.9 3.6 4. 1 .87 45.3 9, 670 2,470 .03 1.4 2. 1 168

S3 - - 8.0 5.0 12.0 .52 18.7 2.9 3.2 .91 45. 4 12. 900 3, 130 .02 1. 2 3. 2 168

• End bearing, 9,510; side bearing, 8,230.

b End bearing, 3,540; side bearing, 1,590.

Table 3.Physical properties of concrete units

Designation

Exterior dimensions Thickness

of face

shell

Weight

Absorption bv

24-hr cold immersion

Compressive

strength Face shell immersed in J-i in. of water

T W L Dry

Per

cubic

foot of concrete

Per

square

foot of wall

area

Net

area Grossarea

Absorption, 3 minutesCapillary

rise in

first hour

Time required

for capillary rise through unit

in. in. in. in. lb lb lb % Iblft 3 lb/in.' lb/in.- glcm 2 in. in. hr m 7.8 11.5 7.7 1. 25 29.4 129 48.

7.9 10.

2, 050 1. 190 0.63 4.6 7.

50

71. . . 8.

11.9 7. 7 1. 30 24. 2 88 37.7 16.

14.0 1, 560 1.000 . 17 4.8 120

V. _ . . - (')2.3 4.0

11.8 "12.4

23.8

8.0

8.

7.7

(")

0. 50

29! 1 13.9

22. 7

126

12588

44.2 7.0

7.4

14.4

8.3

9.7

12.7

2, 240

<i 2, 100 970

930

<! 1, 730

530

.09 0.7 0.5 w

X ' 17.8 . 47 2.3 3.7 78

" Top, 8.5; bottom, 9.0.

i> Face shell indented on inside—maximum thickness 2.25 in., minimum thickness 0.67 in. Indented concrete slabs, similar to those used in the fabricated unit v; also made in 4- and 8-in. widths,

'i Slab loaded on edge, 8-in. dimension vertical.

' Weight of wall 1 unit or wythe in thickness. 445545°~42 2 [7]
i—5-__,

Stretcher an// Boncf/rygr ar?/Y

P0U8LE 5/iELL T/L£, ttarc/ fd)

SmNDAFtD T/L£ (J)

^ . Sfrefcher an/'/' dond/'ng un/f

5PEED-/\-BACH£/f, /iord(f) s/D£ CONSTFUCT/ON TILE (e

)

Sfrefc/ier un/'f Bonding un/Y

EfAB/r/LE (g-)

Figure 4.

Details of structural clay tiles.

Tile p.—End-bearing tile, similar to those

used in the Harlem Housing project. Both

stretcher and bonding units were 2-cell. Used

as backing units in two walls.

Tile g.—Double-wall tile, side-construction,

single-cell. Made at Redfield, Iowa, by the

Redfield Brick and Tile Co. Used in two cavity

walls sponsored by the Structural Clay Products

Institute, in which the cavities were filled with

Palco wool.

Tiles Si, S2, and s^. —These tiles were sidebearing units of special shape, known as "Drispeedwall" tile. Used without brick facings in three walls sponsored by the National Fireproofing Co. Tiles Si and S3 were salt-glazed.

The finish on tile S2 is Imown as manganese-spot.

(c) Concrete units

The concrete units included two kinds of concrete blocks purchased under Federal specification, two kinds of sponsored blocks of special

shapes, and one sponsored unit consisting of

[8]
flat slabs of different sizes. Their physical

properties are given in table 3 ; photographs and

detailed measurements are shown in figures 6 and 7. The concrete units were designated by lowercase letters and their characteristics and use are

listed below.

Block m.—Stone concrete, 2-cell, end-bearmg.

Purchased under Federal Specification SS-C621, type I, load-bearing. Used hi three walls

with brick facings, in one wall without a facing,

and in walls (without facings) for structural

tests; see BMS5.

Block n.—Cinder concrete, 2-cell, end-bearing. Purchased under Federal Specification

SS-C-621, type I, load-beanng. Used in five walls with brick facings.

Block V. —Two stone-concrete slabs connected

Scoring O.lWp -j _ „ „ '

Sfrefcher un/f Bonding un/-/' DOUBLE S/i£LL T/LE, Soff SPfED-A-BAmE/f T/LE, 5of/(Zj

Sfrefc/ien un/f

Scoring

V

HARLEM H0U5//S/G T/LE (p)

Bonc/ing un//

-1^

CO

If

-tlO

DR/-SFEED/^/)LL T/LE (s)

FiGtTRE 5.

Details of sinictural clay tiles.

[9]
irni a .^J J J

///^, fyar^fd) 5/de cons^rac/^on fi/e (e) Speec/-a-be^cker f/k, harcf(f)

Rar/H/e (^y

Speed-a-backer ti/e, so//(l) Doah/e tva// f//e (q)

Doad/e she//h/e, 3of/(/i)

'k h fe » a «

Ma/iJAfedf ,jnaer-co/?crefe b/'ock(xj

1^ 1

Z?/7- Speedkva// ///e (s)

i

/iar/ern dous/ng r//e (pj

Dun-T/-S/one

1

1 1

5fone- concre/e

b/ock (m

)

Cinder- concre/e

block (n)

Duns/one ur?//s (t^)

FiGi'RE 6.

Siriuiural clai/ iilc and concrete units.

by a Yi-m. diameter, Z-shaped, deformed steel reinforcement bar. Slabs were made on a Dimbrik machine of concrete containing 1 part

of Portland cement to 8 parts of bank sand

(passing No. 4 sieve) by volmne. Bars fastened to slal)s by a mortar containing 1 part of

cement to 3 parts of sand by volume. One of the two shells of each unit was inclined from

the vertical. Trade name of fabricated block,

"Dun-ti-stone." Used in one wall, sponsored

[10]
-5f —rLi3TONE CONCRETE

BLOC/1 (m)

- -ICO 00

= 1*

C/ND£/f CONCf^ETE

BLOC/1 (n

)

{

4> Steel Tie Borr-ri 'I'll

I

I

!

I !

III I I : I 1 k.__J k il

tire

CO

DUN-ri-STONE UNIT(v)

DUN5T0NE UNITS (w)

4000000®

MAHL3TEDT CINDf/^-CONCffET£ BLOC/ifx

)

FiGtTRE 7.Details of concrete units. by the W. E. Dunn Manufacturing Co., Holland, Mich., and in similar walls for structural

tests.^ The block were made by the Silver

Hill Brick Corpoialion, Silver Hill, Md.

Unit w. —Flat, stone-concrete slabs, similar

to and made of the same kind of concrete as

« Building Materials and Struclurcs Report BMS22, Structural Pro])-

erties of "Dun-ti-stone" Wall Construction Sponsored by the W. K

Dunn Manufacturing Company.

11
that used in slabs for block v. Made in three

nominal widths, 4, 8, and 12 in. Trade name,

"Dunstone." Used in four walls sponsored by

the W. E. Dunn Manufacturing Co. and in similar walls for structural tests. ^ Block X.—Cinder-concrete, with cored holes,

end-bearing. Manufactured by the Mahlstedt

Materials, Inc., New Rochelle, N. Y. Used in one wall similar in construction to those built for structural tests, sponsored by the National

Concrete Masonry Association.^

{d) Mortars

The sand used in all of the 10 mortars was

washed Potomac River building sand, obtained

from the Smoot Sand and Gravel Company,

Washington, D. C. A sieve analysis, made

from each consignment of sand, is given in table 4. The difference in gradation of the

sands was probably not a significant factor in the permeability of the walls. The cementing material in nine mortars was

a mixture of portland cement and lime; that

used in one mortar was a masonry cement.

Two mortars contained waterproofed portland

cement, five contained lime hydrates, and four

contained a lime putty made by slaking a pulverized quick lime. The kinds of cementing

materials used and the proportions, consistencies, and water retentivities ^ of the mortars are given in table 5. Mortar 2, similar to mortar 2 described in BMS7, was used in a total of 100

wall specimens. Mortars 1, 2, or 5 were used

in walls built for the Bureau, and the other

mortars were specified by sponsors of walls built

of special units. Mortar 6 was used with Hbrick, mortars 7, 8, and 12 wii.h "Speedbrik,"

mortars 9 and 10, as well as mortar 2, with

"Mimlock" brick, and mortar 11 was used with

"Spaulding" brick. All of the portland ce- ments and the masonry cement used in the

mortal's were tested and found to pass the

physical requirements of Federal specifications.

The materials for the mortars were proportioned by weight and mixed in a batch mixer

" Building Materials and Structures Report BMS 38, Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. K. Dunn Manufacturing Company.

« Building Materials and Structures Report BMS21, Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association.

» Determined according to Federal Specification SS-C-181b.

having a capacity of aboiit 0.6 cu ft. When

only one mason was employed, mortar batches were prepared every 20 to 40 minutes. The

amount of water added to the mix was kept in adjustment to the satisfaction of the mason,

and the desired amount used in any one kind

of mortar was found to vary with the absorptive properties of the bricks or with sand gradation. It is evident from table 5 that the mason was satisfied to use a lower initial flow

for the richer mortars, mortai-s 6 and 11, than

for the leaner mixes. A determination of the

flow and of the water retentivity of the mortars was made at least once each day, and it was

found that changes in the water content of a mortar did not greatly aft'ect the water re- tentivity.

Table 4.Sand sieve-analyses

Weight passing U. S. Standard8 16 30 50 100 % % % % %

United States Government " 100 96 81 19 2 Structural Clay Products Institute 100 96 82 24 2 National Concrete Masonry Association 100 96 81 25 2 Brick Manufacturers Association of New York, Inc 100 88 53 9 1 W. E. Dunn Mfg. Co 100 98 81 23 3 General Shale Products Corp 100 96 73 18 2 Munlock Engineering Co _ - 100 88 61 21 3 United States Government --. 99 88 58 11 1 structural Clay Products Institute 100 92 65 14 2 United States Government... . . . 100 91 64 23 4 Average . 100 93 70 19 2

« About three-quarters of the walls were built with mortar made from

this sand.

(e) Grout

The grout used in all but one of the grouted

walls was made by addmg water to moi-tar 2, the total amount of water iii the grout being

equal to about one-third the weight of the dry

matei'ials. The grout used with brick E in a

wall sponsored by the Structural Clay Products

Institute was mixed in the proportions, by

weight, of 1:0.06:1.45:0.63 parts, respectively, of

portLaud cement, hydrated lime, building sand,

and water.

(j) Metal ties The wythes of walls built without header

brick or bondmg units were connected with

metal ties. The ties used in all but one wall were )^-in. diameter steel rods bent to a Z-shape

with an angle of 90 degrees between the out-

[12]
Table 5.

Proportions, consistencies, and water retentivities oj mortars

Mortar

l_

5-6.

7-

8.

9-

10

1112

Proportions of cement, lime hydrate, and

sand"

By volume

1:0.25:3 1:1:6

1:1:6

1:1:5

1:0.3:0.15':3.4.

l:l:0.6e:5.9-,.

1:1:6

1:0:3

1:1.5:5 1:1:6

By weight

1:0.11:2.6

1:0.42:5.1

1:0.42:5.1 1:0.42:4.2 l:0.13:0.13e:2.9

1:0. 42:0.51 '^:5.1 1:0.42:5.1 1:0:3.4

1:0.64:4.3-- . 1:0.42:5.1

Kind of cement ^

Atlas p. 0 do

--.-do Medusa p. c Medusa w. p. p. c -- do

Atlas p. c Hy-test m. 0 - - Atlas p. C - - - .- GreenbaK p. c.

Kind of lime

Putty

do--..

Berkeley-, Putty

Standard

-

Putty

Standard

-

Miracle

-

Grove---

Water content by weight

of dry materials

Min Max

/o 19.7

20. 5

20. 2

22. 6

19. 5

21. 2 20.8

14.9

%

20.2

24.4

22.3

22. 5 19.5

21.8 20.8

14.9

Avg

%

20.0 23.0

21. 3

22. 5

19. 5

21. 5 20.8

14.9 18.7

21.

1

Average

initial flow"

%

115

105

13190 116

97

111 100

78

119

Average water

retentivity

64

Number of walls

built

of each mortar

3 100

14

4

» Proportioning was by weight, assuming that 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. (Hy-Test masonry cement was assumed to weigh 70 Ib/ou ft.)

•> p .c. denotes Portland cement.

w. p.-p. c. denotes integrally waterproofed Portland cement, m. c. denotes masonry cement.

All the cements met the physical requirements of Federal Specifications.

' All the putt J was made from Standard Lime and Stone Company's "Washington" brand, powdered quicklime. Other limes were dry hydrates.

J Determined according to Federal Specifications SS-C-181b.

' Limestone dust, "Cameline" brand, H. T. Campbell Sons Co.

standing legs and the stem. The length of stem was 6 in. and of the outstanding legs 3 in. The ties used to bond a cavity wall built of

"Mahlstedt" cinder block were made of Ke-in. diameter steel wii'e bent to the shape of a

rectangle with outside dimensions of 4 by 6 in. In addition to metal ties, %-in. round steel reinforcement bars were placed in the collar joint of one grouted wall.

3. Construction of the Walls

(a) Procedure

All of the walls were built by skilled masons

under the direction of a representative of the

National Bureau of Standards or of the sponsor

foi' the walls. During theii' construction the

brick-suction ^° was determined and recorded at

intervals of 30 to 40 minutes. When necessary

to meet predetermined limits for the amount of

suction, the brick were wetted by immersion in water before laying, but no brick were laid

while so wet that water was visible on their

surfaces. Usually no water was visible on the

surfaces of the brick 30 minutes or less after

their removal from the bath, especially if the

brick were stacked so as to permit the circulation of air. The joints in the face of some of

the walls were tooled with a rounded steel bar,

and whenever possible the tooling of the joints

10 'phe "brick-suction" is defined as the amount of water, in grams, absorbed by a brick (30 sq in.) placed on the flat side in water to a depth

of H in. for 1 minute.

was done after the mortar had stiffened. The

walls were completed on the same day their

construction was started, and they were aged

for at least 28 days indoors at a temperature of

70° F or higher before being tested.

(6) Designation, of specimens

As the walls were built, they were given consecutive numbers with the prefix B, to identify

them as having been constructed subsequent to those described in BMS7. The walls were

further identified by the following designation:

The first two letters designated, respectively,

the kind of units used in the facing and the

backing. This was followed by the numeral

indicating the nominal thickness of the wall in

inches, and by a capital letter designating the

type of workmanship. The last numeral gave

the kind of mortar used. For example, wall

B43, 12 in. thick, built of class F workmanship,

using brick B for facing units and tile / as backing units, with mortar 2, was designated: Wall

B43-5/12F2.

(c) Kinds oj workmanship

The workmanships differed in the manner in

which the joints were filled with mortar, or in

the extent to which the vertical joints were

filled. When header brick were used, they were

laid in common American bond. Metal ties, when used, were usually placed 24 in. apart in every sixth course and at least K in- from the

[13
Figure 8.

Brick wall of workmanship A'

.

The bed joints arc furrowed and vertical joints are completely filled. Note the mortar on the stretcher brick, which is ready to be placed in one of the backing wythes after the bed joint is placed.

nearest head joint. The method of bondmg the

units in sponsored walls was specified by the sponsor. The workmanships were arbitrarily

designated by capital letters and the different

types are described below.

Type A.—Workmanship A was used in many

walls described in BMS7. For the brick walls,

mortar in the bed joints was spread and leveled

to a uniform thickness, not furrowed. The

head joints were filled and were formed by applying the mortar to the ends of stretcher brick

or to the sides of header brick before placing

them in the wall. The collar joints were filled with mortar and, when necessary, filling of the

vertical joints was completed course by course by slushing in mortar from above. The tech-,

nique employed in filling the vertical joints

varied slightly with different masons or even in different walls built by the same mason. Joints

in the wall facing were tooled with a rounded

iron bar, w"hich formed a concave surface. The contiguous surfaces of adjacent hollow

masonry units were mortared. Mortar was

spread evenly over the flat surfaces of the bed

[14]
joints and was applied to both the inner and

outer shells of the end-bearing units. Head

joints between hollow units were made by covering all the surfaces at one end of each unit

before placing it in the wall. Collar joints were made in the same manner, but it was not practicable to complete the filling of vertical joints

between large units by slushing mortar from

above.

Workmanship A was used in 25 all-brick

walls, in 3 brick-faced walls, and in 3 walls built

of hollow masonry units, without facings.

Type A'.—Illustrated in figure 8 is workmanship A'. This was used in 10 walls and was the same as type A, except that the bed joints,

under the brick, were furrowed, not leveled. The joints in the wall face were tooled. Type B.—Workmanship B was used in many

of the brick masonry walls described in BMS7

and is typical of that usually employed in speculative building construction. Labor and mortar were used sparingly in walls constructed of

this workmanship.

Mortar in the bed joints of brick walls was

furrowed. Head joints were made by buttering

the outer end portions of the brick, leaving the

interior of the joints open. In 12-in. brick

walls, the brick in the center wythes were laid on the furrowed bed without buttering the

head joints. The collar joints between wythes

were left open. The joints in the faces of the

wall were cut flush with the surfaces of the

brick, forming a rough texture. Only the face shells of hollow units were provided with mortar beds, and the head joints were made by buttering the edges of the unit

that were exposed in the face of the wall. Type B was also used to designate the workFiGTJRE 9.

Brick wall of workmanship F.

Except for the parging, this wall is typical ol type B workmanship. Bed joints are furrowed and head joints are buttered at the wall faces. The parging is applied to the rear of the facing wythe before laying the backing wythe. This wall contains no header brick but is bonded by metal brick

ties (not shown). [15]
Figure 10.

Brick-faced wall of workmanship G and G'

.

Parging applied to face of the backing. Head joints in both the hollow units and the brick are buttered only at the wall faces.

mansllip employed in some walls which were

built of special units, and in which the interior

of the joints or the interior of the wall was left open. Workmanship B was used in the construction of 30 walls. Type F.—Workmanship F, illustrated in figure 9, was similar to that used in brick walls

of workmanship B, except that the collar joints

contained mortar pargings. The bed joints were furrowed, and the head joints were buttered at the wall faces. The stretcher courses

in the facing were laid to the elevation of the

header course or to that of the course containing

brick ties. A mortar parging % to in. thick was carefully applied to the back of the wythe

and keyed into the open hea.d joints. The units

in the backing wythe were then brought to the

elevation of the bonding course. If the wall

contauied three wythes, as in 12-in. all-brick

walls, a mortar parging was similarly applied to

the back of the second wythe. The width of the

collar joint was such as to leave a narrow space

between the parging and the faces of the units in the backing. Since the head joints in header

brick were buttered at the edges placed in the

wall face, and not completely filled, the contuiuity of the parging was broken in the vertical

joints at each header course. Walls with brick

facings, and backings of hollow units, were constructed by first laying the brick to the height of a header course. The backs of the brick were

then parged and the backing wythe was laid as

in workmanship B to the elevation of the header

or bonding units. The joints in the wall face were tooled. Twenty-foui' walls were built of workmanship F. Type F'.—Workmanship of type F' was used

in ] 1 brick walls with hollow-unit backings and was similar to that of workmanship F, except

that the head joints between header brick were

[16]
completeh'^ filled, not buttered. The vertical

plane of the pargmg contahied no open joints at the header courses. Type G.—Workmanship G was used in three

brick-faced walls backed with hollow units and

is illustrated in figure 10. It was similar to that

of type F, except that the parging in the collar joint was applied to the backing. The hollow

units were laid to the elevation of the brick

header com-ses, using worlananship B. Bed

joints were placed under the outer shells of the

hollow units, and the head joints were buttered

only at the back of the wall. A mortar parging

% to y2 in. thick was then applied to the backing,

and the brick facing was laid as in workmanship

B to the top of the header course. A narrow

open space was left between the back of the

bricks and the face of the parging. The head

joints in header courses were buttered, not completely fiUcd. The joints in the wall face were

tooled

.

Type G'.—The linul joints hcl w ecu hcadcibrick in walls of workmaiisliip G' were completely filled, not buttered ; otherwise this workmanship was similar to that of type G.

Six brick-faced walls with hackings of ]io1!oa\- units were built with workmanship G'. Type H.—The letter H designates a workmanship used in building eight grouted brick

walls. The method usually followed, and illus- trated in figure 11, was to lay the brick as in type B workmanship, plugging the ends of the

collar joints with mortar, after which a grout was poured as the brick were laid, one course at

a time. The brick in the facing were sometimes laid several courses above the backing

or to the height of the bonding course. WTien

furrows in the bed joints were made close to

Figure 11.

Brick wall of workmanship H, grouted.

Wall B52--BB9H2 under construction. Note the mortar plugs at the ends of the collar joints and the buttered head joints. All the vertical

joints were filled with grout as the backing was laid, one course at a time. [17]
the collar joints to facilitate possible filling of the furrows with grout, it was noticed that

the stretcher brick tipped slightly toward the

collar joints.

The grouts, previously described, consisted

either of mortar mixed with water to a pouring

consistency, or else a special mixture higher in cement content was prepared. Both grouts

stift'ened readily, and they had to be stirred

and sometimes tempered with additional water

as they were used in the walls. One of the

grouted walls (Bl29-££'9Hl) contained deformed steel reinforcement bars placed in the

collar joint. The face joints of grouted walls were tooled. Type J.—Workmanship J was used in three

brick walls built with common American bond.

The brick in all the wythes were laid with

furrowed bed joints, buttered head joints, and

open collar' joints, as in workmanship B. The

vertical head and collar joints were then filled by slushing in mortar from above with the

trowel. This procedure was repeated course by course. Joints in the face of the wall were

tooled. Type M.—Five walls of type M workmanship contained a 2-in. cavity between the

wythes, which were connected by means of metal ties. Mortar for the bed joints was

furrowed, and the head joints in the brick

courses were filled or nearly filled by heavily

buttering the ends of the brick. The head

joints for the tile backings were buttered only on the outer edges. The cavity contained no

projections except the metal ties, and the

mortar joints inside the cavity were cut flush. During construction a timber was supported on the metal ties to catch the mortar droppings,

thus preventing folding of the bottom of the

cavity. The flashings in these walls were

Figure 12.

Brick-faced cavity wall, workmanship M.

Note the brick ties and the cut joints inside the cavity. The head joints in the tile are buttered on back :ace only. This wall was constructed

for structural tests but is typical, except for lower flashing, of cavity walls built for water-permeability tests. [18]
placed to divert possible* leakage to the backs

of the walls, as is shown in figure 1, and not

to divert leakage to the exposed faces, as is usually recommended in specifications for cavity walls. Joints of the brick facings were

tooled. A typical cavity -wall construction

(similar to that described in BMS24) is shown

in figure 12. Type S.—Workmanship S was used in two

12-in., all-brick walls laid in common American

bond. C. W. Hammett, a masonry contractor

of Washington, D. C, directed the construction

of the walls. The stretcher brick in the facing were laid

in furrowed bed joints to the height of the

header course. An excess of mortar was

placed ill the bed joints, so that after placing

each brick, considerable mortar was extruded

from the sides. This extruded mortar was

cut ofl" with a trowel and applied to the end of the next stretcher brick, which was then

placed in the wall with a slight shoving motion,

filling the head joint. Thus it was not neces- sary to obtain additional mortar from the

board to completely fill the head joints. The

back of the facing wythe in one wall (B118) was covered with a mortar parging about

% in. thick.

The brick in the center wythe were laid by

the pick-and-dip method. A full trowel of mortar was dropped in a heap in proper position on the bed. Simultaneously, with the other

hand, a brick was picked from the pile and

shoved into the mortar so as to form the bed

joint and to fill the head joint and the collar

joint. The mortar was usually extruded

slightly above the top surface of the brick in both joints, and it was unnecessary to use the

trowel except to place additional mortar for each brick in turn. No mortar was slushed

into the head or collar joints if they were not

completely filled. A 2- by 4-in. timber was

braced vertically at one end of the center wythe to take the thrust of the shoving operation. Stretcher brick in the backing wythe were

laid in a furrowed bed and the head joints were filled, as in workmanship A'. Since

extruded mortar from the bed joints was cut only from the back of the wall, it was necessary

to obtam additional mortar from the board to

[

completely fill these head joints. No attempt was made to fill the collai' joint between the

center and the backing wythes.

The header brick were laid in a furrowed

bed. Head jonits were completely filled by

buttering the sides of the headers or, when

necessary, additional mortar was slushed in from above. The collar joint between tlie facing and the center wythes at the elevation

of the rear header course (over the center and

the backuag wythes) contained no mortar,

except the thin parging applied to the back of the facing wythe in wall B118.

((/) Construction of Sponsored Walls Built of Special Units

"Tight-wall" bricks (Puddington Sales

Corporation)

Workmanship N, illustrated in figure 13, was used in constructing three walls of "TightWall" brick (bricks R^, R2, and R^) laid in com- mon American bond, with mortar 2. The

bricks were recessed at the ends of stretcher

units and at the sides of headers. The bed

joints were furrowed, and the stretchers in the

facing wythe were laid end to end on the bed

joint without applying mortar to the ends of the

units. Stretcher bricks Ri and R3 were about

% in. longer at one face than at the other; and

the long faces were laid in contact with each

other at the back of the facing ^rythe, so that a

%-in. open joint was left at the head joints in the wall face. Stretcher brick R2 were of equal

lengths front and back and these brick were

laid end to end, about % in. apart. The maximum width of aperture between stretcher

units, measured parallel to the face of the walls, was about 1% in. for brick R^ (wall B300) and

about 1% in. for bricks R2 and R3 (walls B301

and B302, respectively). Mortar was slushed

into the openings between the ends of the

bricks, filling the space between the units.

Header bricks were laid similarly, and both the

front and rear cavities between the header

bricks were filled with mortar.

Common brick of regular dimensions were

used for backing. The collar joint was left open, and the backing stretchers were laid in furrowed beds and with buttered head joints

]
Figure 13.

Brick wall uf workinauship N.

Sponsored construction wall B302 under construction. Note the recessed ends of the stretcher bricks and the sides of the header bricks, which are filled with mortar after the bricks are laid in the wall, without buttering the head joints; the collar joint was left open. The joints in the facing were

subsequently tooled.

as ill type B workmanship. Joints in the face

of the wall were tooled.

"Spauldiiig" bricks (W. H. Spaulding)

"Spaulding" bricks, bricks V and W, were

used as facing units in four walls with mortar 1 1

.

Two kinds of workmanship, types P and Q, were represented, and one wall was built of each kind of facing unit and workmanship.

The "Spaulding" bricks were recessed at the

ends of stretcher units and at the sides of header

units. Bricks with recesses for outside corner work were furnished but not used in these walls. The brick used for backing the walls, brick A", were of the ordinary size and shape. All of the

bricks were laid dry, as received. Mortar of two degrees of temper was used, designated as mortar (mortar 11, table 5) and retempered

mortar, which contained additional water. In type P workmanship, the beds were fur120]
rowed. Head joints between stretchers in the

facing were made by first buttering the outer and inner edges of the units, no mortar being

placed at the center third or recessed portion

of the ends. A portion of retempered mortar was then placed, with the trowel, into the center

of the head joint. Usually two applications were made before each joint was filled. A

rounded and tapered burned-clay dam was

then inserted, pointed end down, into the center

of each head joint. Insertion of the dam

resulted in the extrusion of some mortar from

both faces of the head joint. The clay dams

shown in figure 3 wei-e made of the same kind

of clay as that used in the manufacture of

brick W. They were not hard-burned, and

their average absorption during a 24-hi'. immersion in cold water was about 1 1 percent. Mortar for the head joints between header brick was applied to the outer edges and to the centei' portion of the headers before placing them in the wall. Retempered mortar was then placed

in the open portions of the head joints over each

wythe, but clay dams were placed in the facing

wythe only. The collar joints between the wythes

and the head joints in the backing wythe were

filled with mortar as in work-manship A'. In type Q workmanship the bed joints were

furrowed and the outer edges of the stretcher

bricks were buttered before laying. Retempered mortar and clay dams were placed in the center portion of head joints in the facing

wythe. The insertion of the dams usually

extruded s\ifficient mortar to fill the inner

third of these joints.

The collar joint was open and the stretcher

brick in the backing wythe were laid as in workmanship B. The header bricks were buttered at the ends before laying, and the head

joints between them were similar to those

placed between the stretchers in each wythe.

H-brick (Whitacre- Greer Fireproofing Co.)

Four single-wythe walls (iV8B6) were built

of H-brick. The bed joints were furrowed

over those portions of the brick lying in, and

parallel to, the wall faces. The head joints were buttered over the ends of the units. No

mortar was placed in the center portion of the

walls. The smooth edges of the brick were

placed in the faces and the jomts were tooled.

"Munlock" brick (Muidock Engineering

Comjiuny)

Eight single-wythe, 8-hi. walls were built of "Munlock" brick M. Mortar lor the bed joints was beveled double from the outer edges downward to the base of the longitudinal ridge at the center of the miits. The head joints were

buttered to a depth of 2 or 3 in. from each face,

and no mortar was placed at the center portion

of the wall. The joints were tooled in the ex- posed face of the wall and cut flush with the

units at the back. The brick were air-dry when

laid. The method of constructing the walls was

similar to that described in building walls for structural tests (seeBMS53).

Four walls were built with mortar 9, two with

mortar 10, and two with mortar 2. The brick

tended to float when laid with mortar 9, and

this mortar extruded slightly from the joints.

There was no difficulty noted in laying the

"Munlock" brick with either mortar 2 or 10. "Speedbrik" (General Shale Corporation)

One 12-in. and three 8-in. walls were built of "Speedbrik" 0 with mortar 7, and three 6-in. walls were built of brick 0 with mortar 12. The "Speedbrik" P was used in two walls

with mortar 8. The mortar beds were furrowed under the

double outer shells of the units. The head

joints were buttered in each wall face to a depth equal to the width of the bed joints,

about 1% in. No mortar was placed in the

interior portions of either the 6- or the 8-in. walls. The face joints were tooled. The

method of constructing these walls was similar

to that used in building 6-in. walls of brick

0 for structural tests. "Dri-Speedwall" tiles (National Fireproofing

Company)

Walls B277, 278, and 279 (.s8B2) were built

of "Dri-Speedwall" tiles. These side-bearing

units contained baffles designed to prevent the

penetrations of water through a wall by diverting any leakage downward at the center of the

tile to the bottom of the wall, where, pre- sumably, it could be drained to suitable outlets. No mortar was placed in the interior portion of

" The results obtained from the structural tests will be described in a Building Materials and Structures Report.

[21]
these walls, and the bed joints were placed

under the double outer shells. The head

joints were carefully applied to a depth approximately equal to the width of the bed joints

(IK to 2 in.). The facing joints were struck

and weep holes were placed above the flashnigs, at the rear of the walls, so that the rate of leakage could be measured.

"Dun-ti-stone" and "Dunstone" units (W. E. Dunn Manufacturing Company)

One wall (Bl59-?;8B2) was built of "Dun-tistone" units. The inclined shell of each unit was placed in the face of the wall so that the

bottom of the shell extended over the bed joint.

The bed joints were furrowed on both the face

and back shells. The head joints were buttered over the entire ends of both shells. This wall was similar in construction to those built for the structural tests which are described in BMS22. Joints in the face of the wall were

struck, those in the back were cut. Four 8-in. walls CB231-, 232-, 233-, and 234-

w8B2) were built with "Dunstone" units. They

were similar in construction to those used for the structural tests described in BMS38. Two

of these walls (B231 and 233) were built by

placing 8- by 8-in. header units in a vertical

position at each end of 8- by 12-in. stretcher

units, also laid vertically. Each course was

about 8 in. high. Bond of the vertical joints was broken by using 4- or 8-in. stretchers at alternate ends of successive courses. The other two walls were built by placing 8- by 12-in. header units horizontally at the tops

and bottoms of 8- by 12-in. vertical stretcher

units. Bond of the vertical joints was broken

by using 4- or 8-in. units at the ends of header

courses. Mortar in the bed joints was fin-rowed, and

the head joints were made by heavily buttering

the ends or edges of the units. No mortar was

placed in any of the walls between the inner

faces of the stretcher imits. The sponsor of

"Dun-ti-stone" and of "Dunstone" units re- commends that a protective coating, known as "Mat Glazing", be used on exterior walls built

of these units.

"Mahlstedt" block (National Concrete Masonry

Association)

One wall (Bl23-a:a;10Ml) was built of "Mahlstedt" cinder-concrete block. This cavity wall was similar in construction to those built for structural tests described in BMS21 and sponsored by the National Concrete Masonry Association. The width of the cavity between the

inner faces of the wythes was 2 in. The mortar

beds were furrowed over the 4-in. width of the

top of the block, and the head joints were

buttered only at the outer edges in each face. The sponsor of this construction recommends

that a waterproof protective coating be applied

to the outer faces of exterior walls built of these

units.

III. TESTING OF THE WALLS

Inasmuch as the permeability of masoniy

wall specimens decreases slightly with repeated

test exposures (see BMS7, p. 14, section VI-1),

all of the walls were given a preliminary, or "breaking in", test lasting 2 days. The walls were then dried to nearly constant weight before they were tested for record. The test exposure simulated the effects of a heavy winddriven rain and was the same as that of the

"heavy rain" test described in BMS7.

1. Apparatus and Test Method

The apparatus is shown in figures 14 and 15. The walls were supported on metal skids during

the permeability tests, and they were clamped

into position against the sponge-rubber gaskets

of the testing apparatus so that the exposed

face formed one side of a pressure chamber.

An air pressure was maintained within the

chamber, and water from a perforated tube was

applied to the upper portion of the exposed face

(inside the chamber) at the rate of 40 gal (152

liters) per hour. Since the exposed length of

the wall was 35 in., the amount of water applied

per linear foot of wall per hour was 13.7 gal

(52 liters), an amount sufficient to cover the

wall face with a thin sheet of running water. The applied air pressure was equal to that produced by a head of 2 in. of water, about the

maximum difference in pressure on two faces

of a wall which may be caused by a wind having

a velocity of 50 mph.

The relative humidity of the air in the testing room and of that in contact with the backs of

the walls was usually between 80 and 90 percent.

[22]
Figure 14.

Waier-pemualulitij hs/ chamber.

Face of chamber before placing wall in position. Note streams of water from perforated pipe at top of opening. The temperature of the aii' in the testing room 2. Observations

varied with the seasons and ranged between 50°

iind 75° F. The temperature of the water

apphed to the walls was maintained above the

dew-point temperature of the air in the testingroom, and the water was heated when necessary.

The tests on the walls were continued for not

less than 1 day or for more than 5 days. The

backs of the walls had been painted with whitewash and the discoloration produced by moisture (dampness) on the back could be easily

detected.

Continual observations of the specimens were made for about 2 hours after starting each test, after which the observer inspected the walls at increasingly longer intervals.

The following observations were made during

the tests:

(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

[23]
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.

When not determined during the continual

observation period, the time for leakage or penetration of the walls was assumed to be the

middle of the time interval between two inspections, and the uncertainty of the observations was assumed to be equal to plus or minus onethird of the interval between the inspections.

The highest observed rate of leakage was

assumed to be the maximum rate of flow.

3. Method of Rating Performance

The permeability test is severe, and of greater

duration than the natural wind and rain storms

to which most building walls are subjected.

Figure 15.

Water-permeability test chamber.

Wall similar to B127-j8A2 in position for test. Back of wall not whitewashed (preliminary test).

24
Information of a practical value on the permeability of the specimens may therefore be

obtained during an exposure period of 1 day;

but in ordei' to determine slight difierences

between the performances of the least permeable walls, the tests were sometimes continutnl

for the maximum period of 5 days.

In order to reduce the initial cost of masonry

building walls, plaster sometimes is applied

I directly to the back of the walls, without furring. The test walls were not plastered, and

the arbitrary ratings of wall performance, given

I below, are based on the assumption that visible

I water, extensive dampness on the back, or

j leakage through the base of a wall would damage

, plaster applied directly to the wall or would

injure the interior trim or furnishings of a

building. The exposure given the test walls was

controlled to prevent the condensation of moisture on the backs of the specimens, and

. the probability of condensation damaging

plaster applied directly to the back of building

walls similar to the test specimens was not

determined.

The ratings are not fidly applicable for use

in judging the performances of cavity-type

walls, because, in practice, water penetrating

the facing of such walls is usually diverted by

flashings to the exposed face instead of to the

inside face, as in the wall specimens.

Wall-performance ratings

:

Excellenf {E).—No water visible on back of the wall (above the flashings) at the end of 1 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 {6).—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 (7^).~-Wat(^r visible on back of wall in more than 3 or less than 24 houj-s. Rate of leakage through the wall lo^ss Iban 1 liter per

hour at the end of 1 day.

Poor (P).—Water visible on the l)i(ck in 3 hours 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.

In general, there was little practical difference

between the performances of walls rated as

either "good" or "excellent," and it is possible

that building walls similar to those rated as "fair" in the permeability tests would be considered to have a satisfactory resistance to I'ain penetration except when subjected to rain and

to winds of high velocity for long periods.

IV. DATA AND DISCUSSION

1. Data

Data obtained from the permeability tests are given in tables 6, 7, 8, and 9, which also include the wall-performance ratings. Table 6

gives data on brick walls built of solid or cored

bricks of the ordinary size and shape. Table 7 gives data on sponsored walls containing bricks

of special shapes and sizes. Data on walls with

brick facings and backings of hollow units are given in table 8, and table 9 gives data on

structural clay tile walls and on walls built of concrete units, without brick facings. The

data in table 6 are summarized in table 10 for groups of like wall specimens. Table 11 gives

consti-uction notes on some walls which were

difficult to build.

" 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 0.05

liter per hour.

25]
Table 6.

Perineability of brick walls

Wall Destination"

Brick

suction per 30 St], in.

Approxi- mate

water re- tontivity

of mortar

Kind of

ties 0

Time to failure as indicated by 'i—

Damp Visible water Leak

Maxi- mum

rate of leaka?;e per hour

Area damp in

1 day

Walls or workmanship A

B125

60'.-. B37..

86'__. B64.. B122

B47.

B55. B160

36

B2... B4..

B157

B25_ B158

B3.. B6..

B8-_

B120

B12. Bl..

B135

B20. B16-

B10_ B18.

B5__ B7..

yl^lSAl. ao8A2..-

^lyl8A2_ ac8A2. .. ylC8A2. DD8A2_

CC8A2_.

CC8A2_.

cc8A2._. BB12A2..

CC12A2_.

CC12A2..

.1,112A2_ CC12A5_. BB12A5..

CC12A5.. BB12A2.

CC12A2.

C'C12A2.. BB12A2_

CC12A5.

CC12A5.

CC12A2_. CCI2A5. CC12A2_

CC12A5.

Grams Percent Hours Hours Hours

6 70 HB 4.8

2 85 HB 57. 0 9 80 MT 60.0 "2 10 50 86 HB 84.0

I- B to IS 80 MT 59.0

13 80 HB 0.3 __ 16 80 MT 2. 9 36 ±8 . . 19 80 MT 0. 3 2.3 14 ±6

24 80 MT 3. 6 14 d=6

50 85 HB 0. 3 1.6 1.5

2 80 HB

3 80 HB ""il ±4

3 80 HB 24

11 80 HB 34

3 45 HB 19 ±3

4 45 HB

6 45 HB 34

IS 80 HB 3.0

80 HB 10.0

2'.' SO HB 0. 6 21 35 SO HB . 1 20 45 HB 3. 1 19 ±3

21 45 EB 26.0 - 33 45 KB 0. 7 9 ±3 18 ±3

53 SO HB 10 ±3 18 ±3

49 45 HB 0.8 2. 2 5.0

'

89 SO HB 1.4 18 ±3

120 45 HB 0.3 1.8 1.3^

Liters Percent

0 4 E

0 0 G

0 0 G

0 0 G

0 0 G

0 61 F

0 18 G

.2 100 P

0 !\5 F

1.0 100 P

0 0 E

0 4 G

0 1 G

0 0 G

0 4 G

0 0 E

0 0 E

0 13 G

0 S G

0 26 F

0 37 G

0 32 F

0 0 E

.03 70 F

0 30 F

.5 90 P

0 75 F

4.3 90 P

Walls of workmanship A'

B89. B88.yl.ll2A'2 BB12A'2SO

SO HB

HB

Walls of cored brick scries, workmanship A'

B290

B293

D291 B292 B294

B297, B295 B296

GGSA'2.

(?(73A'2. HnSA'2

H7/8A'2

JJ"8A'2.. JJ8A'2.

.

/iA'8A'2 KKSA'2

9 SO HB 11 ±3

9 SO HB 11 ±3

6 so HB 35

9 so HB 35

9 so HB 5 9 80 HB 11 d=3

9 SO HB 18 ±4

9 80 HB 28

39 ±6

0 7 G

0 11 G

0 0 E

0 0 G

0 22 G

0 20 0

0 1 G

0 0 G

Walls of workmanship B

61 '__ 87ni2i

34 '..

aa8B2 2 acSB2 - . I 2 to 40 i>i;3B2 I 13 CC8B2 . . . 50

85 HB 0.05 0. 05 0. 03 20 80 TP

85 HB .05 .8 .3 25 100 TP

80 HB .03 .05 . 2 34 100 VP

85 HB .03 .06 1.8 51 100 TP

Sec footnotes at end of table.

26
Table 6.

Permeability of brick walls

Wall 1 )ostiimti()ii

Brick

suction

per 30 sq.

in.

Approxi- mate wntw re- tcntivity

of mortar

Time to failure us indicateil bv J— IMaxi- muin

rate of leakage

per hour

Walls of workmansliip F

Area (lamp in

1 day

Katiiij;

.4.48F2 . - .4C8F2 BB8F2 . CC8F2

BB12F2

CC12F2 BB12F5

CC12F5 BB12F2

CC12F2 BB12F5

CC12FS. BB12F2

CC12F2

CC12F5

CC12F2

CC12FS.

Grams Percent

8 80 MT

1> 7 to 20 80 IVl'J' 16 80 IVIT

20 80 MT

i 80 HB

6 80 HB

3 45 HB

6 45 HB

17 80 HB

20 80 HB

27 45 HB

22 45 HB

40 80 HB

47 80 HB

47 45 HB

93 80 HB

116 45 HB

Hours

0. 3

35

42

58.0

.50.0

0. 2 8 ±2

II ±3

1. 3

0. 2

1. 2 0.4

Hours

18 ±3

15 ±(i

3.4

109.0 0.3

i;5. 0

4.0

0. 2

15 ±6

0.7

2.9

14 ±0

4.8

15 ±5

0. 5

0.9

tilers Percent

0 19 F

0 22 G

1 55 P

2. 2 100 P

0 0 E

0 0 E

0 0 E

0

0 0 E

0 0 E

.4 80 P

0 3 G

0 10 G

.4 58 F

13.0 05 VP

0 47 F

Ifi 80 VP

Walls of workmanship H (groutedl

ACm2 « EE9H1 I' BB9H2 8 CC9H2 e ^12H2 > CC12H2I! BB12H2 e

! 8 to 22

1516

24

MT

MT

MT

MT

ur

HB

HB

HB

19 ±3

3."

0. 3

li) ±3 U ±3

2. 6

34

0.4

19 ±3

0 20 G

0 0 G

0 25 P

0 1 G

0 100 F

0 0 G

0 0 G

0 6 G

Walls of workmanship J (slushed)

B34 X412J2.. 9 80 B30.--. BB12J2 17 80 B32... _ CC12J2 23 80 HB

HB

HB

0. 1 17 ±3

1 11 ±2

1 E

6 G

35 F

Waills of workmanship M (cavity)

Bl09i FFl(iM2 11 80 MT 18 ±6 0. 5 3 1 C)

Walls of workmanship S Ceombination shove with pick-and-dip)

BUS .4^1232 9 80 HB 0 0 E

B119 .4.412S2 . 9 80 HB 0 0 E

« The first 2 letters designate respectively the kind of masonry units used in the facing and the backing wythes. The first numeral indicates the nominal wall thickness in inches, the next capital letter designates the type of workmanship, and the final numeral the kind of mortar used.

i> The suction of the brick in the facing is given first for walls containing 2 kinds of bricks.

<• HB indicates that the wythes were tied with header brick, laid in common American bond. MT indicates that the wythes were tied with metal ties, spaced approximately every 6th course. The uncertainty of the observation is given only if it exceeds 10 percent of the total elapsed time. A dash indicates no failure of the wall.

' The wall was similar to one of the constructions described in BMS5.

' Taken from table 8, of BMS7.

s The grout consisted of mortar 2 mixed with about 33 percent of water by weight of dry materials. The grout contained 1:0.06:1.45:0.03 parts by weight of Portland cement, lime hydrate, dry sand, and water. The collar joint of this wall contained

2 vertical and 3 horizontal ^^ in. round reinforcing bars.

i The wall was similar to the construction described in BMS23.

The rating of this wall would have been "good" or "excellent" (instead of "fair" or "poor") if the leakage through the facing had been diverted to (he exposed face.

[27]
Table 7.

Permeability of walls containing bricks of special shapes

Brick suc- Approxi- mate water

retentivity

of mortar

Time to failure as indicated by " —

^^aximum

rate of leakage per hourArea damp

in 1 day Wall Designation » tion per 30

sq. in. Damp Visible water Leak

Rating

Walls containing ' 'Tightwall" bricks, workmanship N

B300 RU8N2

Grams

b 6 to 13 %

85 Hours

0. 05 Hours

0. 05 Hours0.4

Liters

2 %

90 P

B301 i?C78N2 b 4 to 15 85 10 ±3 0 2 G

B302 i?J78N2^.. be to 9 85 114 0 0 E

Walls containing "Spaulding" bricks, workmanships P and Q

B334 WXSFU I' 4 to 35 90 0.2 0.3 0 85 P

B332 TXSPll.^.- b 37 to 35 90 . 1 . 7 2.8

2.8

.3 100 P

B335 H'XSQll » 4 to 35 90 .3 .6 60 F

B333 VXSQll 37 to 35 90 .2 1.0 1.8 2.7 100 P

Walls of H-Brick

B165 NSB& 13 85 0.2 14 ±6 0.

1

3.2 55 P

B166 A^8B6..- 12 85 .5 1.5 6.8 30 VP

B167 iV8B6 13 85 .3 1.3 0.7 30 F

B224 NSBQ.... 11 85 3.0 0.6 3.4 20 P

Average-- _ 12 85 1.0 .9 3.5 35 P

Walls of "Munlock" brick

B259 M8B9 4 55 0.30

.08

0. 30 1. 2 4. 2 85 P

B260 M8B9 4 55 .08 0.3 3.6 85 P

B261_... M8B9 4 55 .04 .9 2.6 75 P

B262 M8B9--_ 4 55 . 04 .60 1.6 3.2 85 P

Average 4 55 0. 1 1.0 3.4 80 P

B267 M8B10 4 65 3. 6 1.8 1.4 25 P

B268 M8B10-- .... 2 65 0. 5 3.5 4.0 0.3 75 F

Average . . 3 65 2.0 ('') 2.9 0.8 50 F

B269 M8B2 5 80 2.7 0 30 G

B270 M8B2.._ . 9 80 4.6 0 3 G

Average .... .... 80 3.6 0 15 G

Walls of "Speedbrik"

B229 P8B8 6 90 18 ±3 0.02 0 E

B230_ P8B8 6 90 0. 5 .25 0 F

Average * 6 90 9 0. 13 0 F

B225 08B7 20 60

60

39 ±6 0.4 0.9 4 F

B227 08B7-... . 20 6.4 .3 2.4 5 P

B228 08B7.... 20 60 5.4 . 5 0.8 4 F

Average . 20 60 17 0.4 1.4 4 P

B226 0012B7. 20 60 0. 2 3.0 5 P

B336 06B12 20 64 2.4 2.7 0.7 70 F

B337 06B12 20 64 0.2 0. 8 2.8 75 P

B338 06B12 20 64 1.8 4.3 0.4 40 F

Average . . . 20 64 1. 5 2.6 1.3 60 P

= See note "a", table 6.

i> The suction of the brick in the facing is given first, for walls containing two kinds of bricks. The uncertainty of the observation is given only if it exceeds 10 percent of the total elapsed time. A dash indicates no failure of the wall.

^ The data from tests on individual specimens show a wide dispersion.

[28]
Table 8.

Permeability of walls with brick facings and backings of hollow units

Average

brick suction per

30 sq. in.

Time to failure as indicated by <

Maximum

rate of leakage per hour

Area damp

in 1 day Wall Designation" Kind of baclting >> Damp Visible water Leak

Rating

Walls of workmanship A

B40 B/tl2A2 Grams

19

1616

End-.

Hours

0.4

1.3

0. 2

Hours Hours Liters 0

.2 2.3

%

7 80

55

GFP

Bn2A2__. Side--- 14 ±6

0.3

14 ±6

B49 Bml2A2 Cinder - 1. 2

Walls of workmanship F

Bdl2F2_

Bkl2F2.

Bel2F2..

B/12F2-- Bml2F2

Bnl2F2_

End—

do.

Slde--- dodo. Stone.

-

Cinder

1. 5 3.3

1. 5 0.3

1.5

0.

1

. 2

2.2 10.08 22 G

18 ±4 2.0 .98 37 F

1. 5 15 ±6 .01 70 P

0. 5 0. 6 13. 50 65 VP

1. 7 3.5 5. 50 67 VP

2 ±0.4 0.3 3. 20 70 P

2.0 . 5 6. 10 70 VP

Walls of workmanship F'

B276-

B275.

B84..

B85.. B131

B133.

B75-.

B86.. B87--

B91--

B90..

Ajl2F'2. Xn2F'2.

BfcliF'2- Bdl2F'2-

Bgl2T'2.

Bpl2'P'2. B/12F'2-. BA2r'2-

Bel2F'2-. Bml2F'2

Bnl2F'2-

5 End

4 Side.--

16 End 0.5

18 do 2.8

13 do--.. 9 ±2 9 ±2

15 do- 19 ±3

14 Side 0.3 1.6 2.5

16 do 4.0

15 do 0.2 0.7

15 Stone14 Cinder - ___ .5 15 ±6 15 ±6

0 0 E

0 0 E

0 15 G

0 20 G

.3 39 F

0 11 G

2.2 80 P

0 20 G

0 35 P

0 0 E

.03 25 F

Walls of workmanship G

B41_ Bfcl2G2 19 End 1.

1

1.

1

1.8 1. 7 52 P

B50 BZ12G2 18 Side 2. 5 15 ±6 0 50 F

B53 Bnl2G2 16 Cinder 4.2 15 ±6 15 ±6 .3 14 F

Walls of workmanship O'

B114_

B132.

B134.

B128.

B117.

BllO.

B/£l2G'2.

Bi7l2G'2.. Bpl2G'2.

B?12G'2-. Bml2G'2,

Bnl2G'2-

End—

do.

do.

«ide... Stone. Cinder

3.4 43.0

99.0

43.0 0.6

10 ±3

103

15 G

17 G

0 E

0 E

22 G

5 E

Walls of workmanship M (cavity walls, bonded with brick ties)

B124 . B271

B271 '- B272 '-

EelOM2-

LglOM2-

i5lOM2- i5lOM2-

Side..do. ^doV

10 ±2

0.2

18 ±4

10 ±3

0.2

.2

. 5

0.3

2.3

3.9 0.8

5 (•) 4 w

20 (•) 10 w

» See note "a", table 6. ^ Legend: Side—denotes side-construction structural clay tile. End—denotes end-construction structural clay tile. Cinder—denotes cinder concrete block, end construction. Stone—denotes stone concrete block, end construction.

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

d The flow at the end of 1 day was 0.02 liters per hour.

« See note "k", table 6.

' Test made after filling the cavity with Palco wool.

[29]
Table 9.

Permeability of structural clay tile and of concrete unit walls

Wall Designation » Method of laying units ^

Time to failure as indicated by

Maximum

rate of leakage per hourArea damp

in 1 day Eating

Damp Visible water Leak

Walls of structural clay tile, /

B126 = ;8A2 End

Hours

0.03

.01

Hours

0. 03

.01

Hours

0. 07

.03

Liters

7. 7 27.0 %

50 100 VP

B127 « /8A2 Side VP

Walls of "Dri-Speedwall" tiles, s

B277 s8B2 Side 1.1 0.3

2.2

0.5

.6

.3

12

4 m

m

m

B278 s8B2 do

B279 s8B2 do

Average. . . 1.2 0.5 2 F

Wall of stone-concrete block, m

B130 ' m8A2 End 0.04 0.04 0.08 54 90 VP

Wall of "Dun-Ti-Stone" stone-concrete block, v

B169 !)SB2 . . . . ^ End 1.7 0. 09 13 13 VP

Walls of "Dunstone" stone-concrete units, w

B231 W)8B2 («) 0.3

.4 0.3.4

0.

1

. 1 5020

90

80 VPB233 !/'8B2 (')^--- VP

B232 y;8B2

Average. -

(')

0.4 0.4 0. 1 35 85 rp

0.1.050. 1 .070. 2.07 42

43

10095 VP

B234 MI8B2 (f) VP

Average .. _ 0.1 0. 1 0.

1

42 95 VP

Cavity-type wall of "Mahlstedt" cinder-concrete block, j

B123 xjlOMl End 0.2 0.2 0.08 103 e65 VP

» See note "a", table 6. b End denotes units laid with cells vertical. Side denotes units laid with cells horizontal.

= The wall was similar to one of the constructions described in BMS5.

d See note "k", table 6.

< Header units laid vertically, on edge (see BMS38, wall CF).

' Header units laid horizontally, flat (see BMS38, wall CG).

e Percent of damp area on back after 6 hours' exposure, when test was stopped.

2. Effect of Workmanship on

Permeability

Workmanship was the most important factor

affecting the permeabihty of the walls described

in BMS7 ; and it was found that walls of workmanship A, in which the vertical joints were

completely filled, were markedly less permeable

than walls of workmanship B. In the walls

of most of the workmansliips described in this

paper, the vertical joints, particularly the collar

joints, were filled with mortar, or grout, or were parged. Since the brick suction and the

water retentivity of the mortar were found to

affect the permeability of the specimens described in BMS7, the comparison of workmanships (tables 6 and 10) is made for walls

having approximately equal values for the

brick suction and for the water retentivity

of the mortar.

[30]
Table 10.

Effect of workmanship on permeability of brick walls

Workmanship

Nominal

wall thickness Number of walls

Range of brick

suction of facing brick

water

Ti^tp n t i Vi t V

U L lllVfl KiCll

Average time for failure as indicated by'— -Average maximum

rale of leakage

per hour

AVeitlge

area damp in

1 day

Hating

Damp Visible water Leak

Inches Gra ms % Hours Hours Hours Liters Percent

3 0 to 10 75 43 Q I g b 4 0 to 10 85 48 Q Q Q

g 3 10 to 20 80 1. ^ 20 28 07 55 F

8 1 20 to 40 80 3.6 14±B 0 95 F

12 4 0 to 10 80 47 Q 2 G

Ai>. 12 b 4 0 to 10 85 0 0 E

12 3 0 to 10 45 27 Q ] E

12 1 10 to 20 80 3 0 15 Q

12 3 20 to 40 80 4 139 Q 25 G

Ab 12 b 4 20 tn 40 85 24 (") 0 10 G

12 3 20' to 40 45 10 49 0 35 G

12 1 40 to 60 80 10 18 0 30 F

12 b 4 40 to 60 85 { 0 25 (c) 12 1 40 to 60 45 0.8 2.2 5.0 90 P

12 1 90 to 120 80 1.4 18 0

° 75 F

A 12 1 90 to 120 45 0.3 1.8 1. 3 4. 3 90 P

^' g g 0 to 10 80 19 0 g G

12 1 0 to 10 80 42 0 0 E

\' 12

g

1 10 to 20 80 54 0 0 G

gb b 4 0 to 10 85 0. 05 0. 10 0. 05 21 70 VP

E ___ 8 1 10 to 20 80 .03 .05 . 2 34 100 VP

Bi> 8 b 4 30 to 40 85 .02 .03 !05 53 100 VP

Bi" 8 b 4 40 to 60 85 08 10 00 81 100 VP

Bb 12 b 4 0 to 10 85 ^80 (") '08 17 45 VP

B>> 12 b 4 30 to 40 85 .07 .08 .03 60 90 VP

Bb 12 b 4 40 to 60 85 .3 5.0 10.0 62 85 VP

g 2 0 to 10 80 . 5 33 0 20 G F 8 2 10 to 20 80 . 5 9 8 1.6 80 P

p 12 2 0 to 10 80 80 0 0 E

F 12 2 0 to 10 45 80 0 0 E

12 2 10 to 20 80 57 0

. 2

0 E

F 12 2 20 to 30 45 4 33 37 40 G

F 12 2 40 to 60 80 6 26 31 '.2 35 G

12 1 40 to 60 45 0. 2 0.2 0. 5 13 65 VP

F 12 1 90 to 120 80 1. 2 15.0 0 45 F

F 12 1 90 to 120 45 0.4 0.7 0.9 16 80 VP

9 2 0 to 10 80 27 0 10 G

H. _ - 9

912

12

1212

12

10

12

1

12

11

1

1

2

10 to 20

20 to 40

0 to 10 20 to 30

0 to 10

10 to 20

20 to 30

10 to 20

0 to 10

7580

80

80

8080

80

80

80

10

11 37

19 u0

0

0

00

0

3

0

10 100

0

3

16

35

1

0

GF

G

GE

GF

(«•) E

H-.^ H

H 17

0.1 17.0

1.0

13

TJ . . J_ 11 M 0.5

S

« Data on the performances of the individual specimens are given in table 6, unless otherwise noted,

b Taken from table 7 of BMS7.

= Not determined.

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

« See note "k," table 6.

(a) Brick Walls

Table 10 summarizes the data for the individual wall specimens listed in table 6 with

respect to the significant factors, such as workmanship, wall thickness, brick-suction, and

the water retentivity of the mortar. For low

values of brick-suction the representative walls

(table 10) of all workmanships except those of type B were rated as "good" or "excellent."

For brick-suctions of 10 g or more, the 8-in. walls representing workmanships A, A', and H,

in which the vertical joints were completely

filled with mortar or with grout, were less per- meable than the parged walls, workmanship F,

of the same thickness. When the bricksuction exceeded 40 g, the 12-in. walls of workmanships A, A', H, and J were slightly less per- meable than walls of workmanship F. All of the walls of workmanship B ^^'ere highly

permeable.'^

The two wythes of many 8-in. walls were

Similar data on the water permeability of brick masonry walls were

Riven by R. E. Copeland and C. C. Carlson, Tests of tite resistance to rnin penetration of walls built of masonri/ units, Proc. Am. Concrete Inst. 36. 169 (1940).

[31]
bonded with metal ties instead of with header

bricks. Wall Bl22-Z)7>8A2 was bonded with

header brick; and at the end of 1 day in the test chamber, the back of the wall showed three

damp belts, extending across the wall, at each

header course. The extent of the damp area was so large that the performance of the wall was rated as "fair." The time required for moisture to rise to the tops of bricks D and C,

when these units were placed on end in )i in. of water, was 11 and 1.7 hours, respectively. In

the test, however, the time required for the

penetration of moisture through header courses

of bricks D and C (walls B122 and 36, table 6) was only 0.3 hour. The data for 8-in. walls of workmanship A indicate that the method of bonding (metal ties or header brick) had little effect on the permeability of walls faced with

low- or with medium-absoi-ptive bricks, but that

the use of high -absorptive header units instead

of metal ties did increase the permeability of the walls. Tooling of the face joints in brick walls had

an important effect on permeability. Walls of

workmanship A, with tooled joints, were markedly less permeable than similar walls in which the joints were cut flush with the sur- faces of the bricks (table 6 of BMS7) . The test results for walls of workmanships A and B,

listed in table 7 of BMS7, are in close agreement

with those obtained from similar walls described

in this paper.

(6) Brick-faced walls hacked with hollow units

The data on the individual performances of

brick-faced walls backed with hollow units are

listed in table 8. With the exception of walls of

workmanship G', containing a mortar parging

applied to the backing wythe, the permeabilities

of individual specimens of like workmanship

show a wide dispersioia, and it is probable that

differences in the watertightness of the 4-in. brick facings affected the performances of these

walls. The data on walls of workmanships F, F',

G, and G' show the importance of watertight

joints in the header courses of parged walls of common American bond backed with hollow

units. The interior portions of the head joints

between header bricks in walls of workmanships F and G permitted the passage of leakage

water through the plane of the parged collar

joint. When these head joints were solidly

filled with mortar for the full length of the

header brick, as in workmanships F' and G',

the permeabilities of the walls were greatly

decreased. Although walls of workmanships

F' and G' were usually rated as "good," those

of workmanship G' were the least permeable.

However, in building constructions in which

type G' workmanship is used, it may be

necessary to install adequate flashings around

wall openings and at floor levels to prevent

breaking the continuity of the protection given

by the pargings at these points.

One of the three walls of workmanship A,

B49-5nl2A2, leaked badly and was rated as "poor;" the others were rated as "fair" or "good." In general, for similar workmanship,

mortars, and values of brick suction, the per- formances of brick-faced walls with backings

of hollow units were less consistent than those

of 12-in. all-brick walls, and the all-brick walls were also less permeable.

The walls backed with end-bearing units were slightly less permeable than those backed

with side-bearing units. The permeability of the walls was affected by the watertightness of

brick facings, and leakage through the facings

probably penetrated to the backs of sideconstruction units at higher elevations than was the case for walls backed with end-construction units.

(c) Cavity walls

Cavity walls are extensively used in England,

where they have given excellent protection

from wind-driven rains when properly flashed over wall openings and at the bottom so as to divert possible leakage to the outside. When

so constructed,^* the penetration of water

through the facings has been of minor importance so long as there was no bridge permitting

the leakage to penetrate the inside face of the

walls. The cavity walls tested in this investigation

failed through leakage at the base, and there was usually little or no dampness observed on

the backs of the walls above the base course.

" Information on cavity wall construction is contained in the book

"Principles of Modern Building," by R. Fitzmaurice, vol. 1 (Building Research Station, His Majesty's Stationery Office, London).

[32]
It is evident, from the data, that wall Bl69

(table 6) and walls B124, B271, and B272

(table 8) would all have been rated as "good"

or "excellent" if the flashings in these speci- mens had been reversed so as to divert the

leakage to the exposed face. Without such

flashmgs, however, the performances of the

I walls would have been rated as "fair" or "poor."

i The cavities m walls B271 and B272 were

filled ^vith. Palco wool (shredded redwood bark

furnished by the Pacific Lumber Co.). The

amount of wool placed in the 2-in. cavities was

about 0.7 lb/ft.2 Wall B272 was filled when

buUt, but wall B271 was tested both before and

after filling the cavity. The back of wall B27 1

,

with the cavity open, was penetrated by moisture in 10 hom-s, but m the second test (with

the cavity filled) a damp area appeared on the

back in 0.2 hour (see table 8). The facing of wall B272 was much less permeable than that

of wall B271. and it requu'ed an exposure pei-iod

of 18 hours before moisture appeared on the

back. After the tests, when the backing wythes

were carefully removed, the Palco wool in both

walls remained standing. Water was visible at only a few points on the back of the filluigs, but

the inside of the brick facing wythes were

dripping wet. The Palco wool contained about 14 percent of moisture by weight before it was placed in the

walls. After the tests, the amount of moisture

in the fillings was nearly 50 percent at the bottom and about 20 percent at the top of the walls.

3. Effect of Brick-Suction on Perme.\bility

Brick-suction, an absorptive property of the

brick at time of laying, was one of the most important factors aft'ectmg the permeability of

brick walls. For like worlcmanships and similar mortars, the data in table 10 indicate a consistent increase m permeability with mcrease in the value of the brick-suction up to 60 g per

brick. Walls containing low-absorptive bricks

or those in which the absorption of the bricks

at time of laying was reduced by prewetting were the least permeable. For equal performance ratmgs, 8-in. brick waUs of workmanships

A, F, and H required a lower brick-suction than

(lid 12-hi. walls. The eft'ects of brick-suction were most pronounced in brick walls of workmanship F, in which the head joints, particularly those between header bricks, were not

completely filled. The rate of leakage through

the highly permeable walls of workmanship B

also increased with increase in the value of

brick-suction. It is evident (table 6) that fUling

of the vertical joints in brick walls did not al- ways result in a "good" or " excellent" performance unless the brick-suction was less than 10 to 25 g depending upon the wall thickness and the

kind of materials used.

Data in table 8 indicate that brick-suction

greatly aft'ects the permeability of brick walls

backed with hollow units. Walls B275 and

B276, of workmanship F', were faced with brick

A after the suction of these brick was reduced

from 10 g, by prewetting, to about 5 g. These

walls gave excellent performances and were less permeable than similar walls faced with brick

B. in which the brick-suction was about 15 g.

4. Effect of Water Retentivity of the

Mortars on Ease of Construction and on

Permeability

The mason experienced difficulty in building some walls of bricks that had been wetted, especially when the bricks contained large amounts

of absorbed water. For example, the highabsorptive brick C each contained about 0.7 lb

of water when the brick-suction per unit was 10

g or less. Regardless of the kind of mortar used,

walls buUt of brick C, having the above value

of brick-suction, tended to bleed (become wet on

the surface) and to spread out of alinement.

However, the bleeding was more pronounced

when mortar 5, which had a water retentivity

of 45 percent (see table 5), was used than for mortar 2, which had a water-retentivity of 80

percent. Notes on the relative difficulty ex- perienced in building brick walls with mortars

2 and 5, taken from the construction records,

are given in table 11. The table does not list all of the walls on which similar observations were made.

[33]
Table 11.

Effect of brick-svction and of the water retentivity of mortar on the ease of constructing some brick walls

Designation

CC12A2. CC12A2

BB12ArK CCUA5

CC12A5_

CC12A.5_ CC12A5_

CC12A2.

BB12F2

CC12F2 BB12F5

CC12F5_

BB12F-1

CC12F5. CC12F5_

Average

briclJ suction

Orams

33

4

3

3

5 27

22 116

Average

water re- tentivity

of mortar

Percent

80

80

45

45

45

45

45

Comments from construction records

Bleeding, not excessive. Joints tooled 5 hours after laying Bleeding

Severe bleeding. Mortar dropping from head joints Bleeding, more than that noted for B157

Severe bleeding

Excessive bleeding. Head joints extruded from face after cutting Although wet, the mortar curled away from edges of brick The mason stated that the brick were laid easier and faster than those used

for walls 3 and 4. Some bleeding, but the parging was applied to backs of the wythes without

difficulty. Considerable bleeding

Excessive bleeding. Difficult to apply the parging.

Bleeding. More difficult to apply parigng than for wall B15

Mortar hardened rapiilly in joints Bleeding—parging droppeil olT and was replaced Mortar for head joints did not stick well to buttered edges of brick

» Bleeding is defined as the separation of water from the mortar in the joints, the released water dripping from the faces of the wall to the floor. Severe bleeding was marked by extrusion of mortar from the joints.

Brick Cwere easily laid with moi'tar 2 in walls

of workmanship A wlu'ii the brick-siiction was

greater than 10 g, but severe bleeding was

noted during the construction of similai- walls

built with mortar 5 for a suction of 20 g (see

data on walls B20- and Bl35-m2A5, table 11).

Similarly, for brick suctions of 10 g, mortar 2 was easily applied as a parging to the backs of the wythes in walls built with workmanship F,

whereas pargings of mortar 5 did not adhere

well to the bricks and sometimes had to be

replaced. It was difficult to use mortar 5 with

bricks having suctions of 50 g or moi'e, because

it stiffened rapidly after being in coiitact with

the bricks and there was little adhesion of the

mortar to the edges of the units when it was

applied by buttering.

The bleeding and the extrusion of mortar

from the joints did not increase the permeability

of the walls (see table 11); and it was noted

that when the bricks tended to "float" slightly,

the walls usually had a high resistance to moisture penetration. For suctions of over

40 g the brick walls built with workmanships A

and F with mortar 5 (low water retentivity) were much more permeable than similar walls

built with mortar 2 (see table 10). Corroborative data on the effects of the water retentivity

of the mortar on both the permeability and on

the ease of constructing brick walls are given in BMS7. The most satisfactory mortars had a

liigh water retentivity and an initial flow

greater than 100 percent. The relative proportions of cement and lime had little practical

effect on either the permeability of the walls or the ease of constructing them.

In general, the masons who constructed the

walls disliked to lay bricks that had been

wetted, because of the abrasive action of such

bricks on the damp skin of the fingers. They

also preferred to use mortar 2 rather than

mortar 5, and then- complaints about the bricks

being either too dry or too wet were usually

made when using mortar 5. The walls that were rated as "good" or "excellent" and that were also easily constructed were built with

mortars having a high water retentivity, using

low-absorptive bricks or medium-absorptive

bricks that had been prewetted.

5. Effect of Properties of Unit on

Permeability

(a) Absorptive Properties of the Bricks

The data, table 6, show that the "suction"

of the bricks i-ather than their total absorptive

capacity when dry was a principal factor affect- ing wall permeability, and for low values of brick-suction the performances of walls built

of high-absorptive brick was comparable to those of walls built of low- or of mediumabsorptive units. Test walls with facings of lowabsorptive brick and with backings of highabsorptive brick were usually more resistant to water penetration than similar walls containing

only low- or high-absorptive bricks (see table (i

[34]
for 8-in. walls of workmanships A and F).

The liigii-absorptive brick C were difficult to lay when they had either a very high or a very

low suction, and such units may therefore be

preferred for backing, with the brick-suction

adjusted to the satisfaction of the mason.

(6) Cored Holes in Bricks

In order to determine the effects of coring

bricks on wall permeability, two walls were

built of the cored and two of the solid bricks

from each of two plants. The cored and the

solid bricks from each plant were alike except

for the coring and for a slight difference in the

iiardness to which they were burned (see table

1, bricks G, H, J, K). The walls were built of

workmanship A' with mortar 2. The Belden

bricks (bricks G and H) were not wetted, but

the "suction" of the Acme bricks was reduced

to a value of 9 g, which was approximately

that of the Belden bricks.

There was no bleeding or spreading of the

wythes noted during the construction of any of the eight walls, but the mason remarked that

the solid Belden brick had a slight tendency to

float, which the cored (harder burned) Belden

brick did not have. Although the mason

placed about the same amount of mortar in the

bed joints of all the walls, the cored bricks

tended to settle in the mortar bed, and the walls

containing the cored bricks were of less height

than those containing the solid bricks by onehalf a course in 18 courses. The data for the individual walls (walls of the

cored brick series, table 6) show that all had a high resistance to water penetration. Walls

containing the cored bricks (bricks H and K)

were significantly less permeable than those

containing the solid bricks (bricks G and J),

but the differences in permeability were of little practical importance.

{c) Brick of Special Shapes

Data on the permeability of sponsored walls,

built of bricks of special shapes, are given in table 7. Although the performance I'atings of the walls listed in table 7 are informative, a fair comparison of the water permeabilities of the

different kinds of units is difficult to make be- cause of the wide diversity in construction

methods, in the kinds of mortar, and in the

absorptive properties of the units, which w(>re

not wetted but were laid as received.

One of the 8-in. walls built of "Tightwall"

brick, B300, leaked badly and was rated "poor";

the others were rated "good" or "excellent."

Since no mortar was placed in the collar joints

of the walls, their resistance to rain penetration

depended greatly upon tlie watertightness of the head joints in the wall facings. Even so, their performances were comparable to those

of 8-in. all-brick walls of workmanship A' or F. The 8-in. walls faced with "Spaulding" briclvs were rated either "poor" or "fair." Mortar 11,

used in these walls, was much richer than most

mortars, and the initial flow averaged less than

80 percent (see table 5). The mortar was

"fat," and it is not ls;nown if the comparatively

high permeability of the walls resulted from the mason being satisfied with an extraordinaiily

low water content in the mortar, which in turn may have prevented a good bond of the brick

to the mortar. The least permeable of the

walls, wail B335, was built with worlananship

Q, ordinarily not expected to be as good a type

of workmanship as type P. The high bricksuction of the facing bricks in walls B332 and

B333 was a factor in the low rating given these

walls. Had these bricks been wetted before

laying and if more water had been used in the

mortar, it is probable that the performance

would have been greatly improved.

The mortar used in the 8-in. walls built of H-brick was rich, and the initial flow was 90

percent (see table 5), which is lower than that

usually desired by most masons. The average

performance of these walls was poor. It is possible, as in the case of the walls containing

"Spaulding" bricks, that if more water had

been used in the mortar the performance of these walls would have been better. Even so, the performance of the walls containing either

the "Spaulding" or the "H" bricks was better

than those of 8-in. all-brick walls of workmanship B (see table 6). A different mortar was used in each of three

groups of 8-in. walls buUt of "Mmilock" brick.

Tests on masonry mortars made by M. O. Withoy show a largo increase in bond strength between brick and mortar when the initial flow

of the mortar was raised. Recent Experiments on Masonry Building

Materials Made in the Materials Testing Laboratory of the University

of Wisconsin, Univ. Wis.. Eng. Exp. Sta., Reprint 53.

[35]
The workmanship used in constructing all of the

walls was alike, and the average permeability

of each group was found to decrease with in- crease in the water retentivity of the mortars.

The water retentivity of mortars 9, 10, and 2 was 55, 65, and 80 percent, and the respective

performances of walls containing these mortars were rated as "poor," "fair," and "good" (see

table 7). Nine walls were built of "Speedbrik" re- ceived from two different plants, one in Ohio

and the other in Tennessee (see description of the "Speedbrik" walls). The brick suction

for the walls built with Ohio "Speedbrik"

(brick P) was 6 g and that of walls built with

Tennessee "Speedbrik" (brick O) was about

20g. The average performance of 8-in. walls

built of the Ohio brick with mortar 8 (water

retentivity of 90 percent) was rated as "fair,"

while that of 8-in. walls built of Tennessee

units with moi'tar 7 (water retentivity of 60

percent) was rated as "poor." Most of the

"Speedbrik" walls failed by leakage from the

flashings regardless of wall thickness (see table

7), but 6-inch walls of Tennessee brick were

also penetrated at the back above the flashings

by moisture which spread over about 60 percent

of the wall area. The 8- and 12-in. walls of the

Tennessee brick were only about 5 per cent

damp.

The head joints in the sponsored walls containing large units, such as H-brick, " Alunlock"

brick, and "Speedbrik, "were not completely

filled with mortar, but they were filled to a

greater deptli than was usual for the 8-in. brick walls of workmanship B, listed in table 6. The performances of the sponsored walls containing these units were better than those of brick walls of workmanship B; they were comparable to those of 8-in. brick walls of workmanship F, but were not so good as those of walls built with workmanships A or A'. The

data (table 7) indicate that the eft'ects on

permeability of variation in the water retentivity of the mortars, and of the brick-suction

of the sponsored luiits, were similar to those

noted in walls containing brick of ordinary

size and shape.

{(1) Structural Clay Tile or Concrete Units

The performances of walls of sti-uctural clay

tile and of concrete units laid without facings

of brick are given in table 9. Two of these

walls contained standard 8- by 12- by 12-ia.

tile (tile j) and one contained 8- by 12- by 8-in. stone concrete block (block m) . The remaining

walls listed in this table were built of sponsored

units.

The effect of laying the structural clay tile j on end or on the side (cells respectively vertical or horizontal) may be obtained by comparing

the performances of walls B126 and B127,

table 9. Both walls were highly permeable,

but the rate of leakage through wall B127, with

tile laid on the side, was nearly four times that

of wall B126. The shells in the head joints

of the side-bearing tile were difficult to butter,

and much less mortar was used in them than for

the solid head joints in wall B126. It is probable that the comparatively high rate of leakage through wall B127 was due to the

greater permeability of the head joints.

The backs of walls B277, 278, and 279 buUt

of "Dri-Speedwall" tiles were not penetrated

by moisture, and the baffles in these units

efl'ectively diverted leakage to the bottom of

the walls. As in the case of cavity-wall

specimens, these walls may be rated as "good"

to "excellent" or "fair," depending upon what

provision is made for the disposal of leakage

water. Even so, with leakage diverted to the

inside face, these walls gave the best performances of any listed in table.

9

After wall B279 had been tested for several

days, thi-ee holes were drilled in the upper

head joints of the exposed face. When the

test was resumed, the leakage rate through

the facing increased to 18 liters per hour and

several joints in the inside face became damp

in about 14 hours, but there was no water

visible above the flashing.

The rate of leakage through walls of concrete

units was much greater than that observed for walls built of structural clay tile. The walls of concrete units were more permeable to air than were the tile walls, and it was not always pos-

[36]
sible to maintain an air pressure of 10 Ib/ft^ in the test chamber until after the concrete units

in the specimens had become wetted. Except

for the walls built of "Dri-Speedwall" tile, it is evident that all of the constructions listed hi table 9 require protective coatings or treat- ments, such as brick or stucco facings, paints, or waterproofings, in oi'der to have a satisfactory

resistance to wind-driven rains. As part of a later investigation the exposed

face of wall B123, of "Mahlstedt" cinder- concrete block, was treated with a cementwater paint, and the performance of the wall,

after painting, was "excellent." The walls of "Dunstone" and of "Dun-ti-stone" units were

not so treated, but it is probable that they would

have given excellent resistance to water penetration if they had been.

V. SUMMARY

1. Brick walls, in which labor and mortar

were used sparingly, so that the interior of the

vertical joints were left open and not filled with mortar, were highly permeable and leaked

excessively.

2. Brick walls, in which the vertical joints were filled with mortar or grout and built of bricks having a low "suction" when laid, were

highly resistant to water penetration.

3. There was little practical difference in the

performance of walls in which the vertical joints were filled (a) by heavily buttering the bricks

with mortar before placing them in the wall,

(b) by slushing mortar mto the joints from

above, (c) by pouring in a grout, or (d) by

shoving the bricks into a heap of mortar placed on the bed (pick-and-dip method).

4. Twelve-inch brick walls in which the head

joints were lightly buttered at the exposed faces

only, but which contained a mortar parging

applied to the backs of both the first and second

wythes, were highly resistant to water penetration. Eight-inch walls of this type were more

permeable than similar 8-in. walls in which the

vertical joints (head and collar joints) were

completely filled.

16 Tests of the water permeability of masonry walls by R. E. Copeland and CO. Carlson show that plain (unpainted) concrete masonry walls were highly permeable. Proc. Am. Concrete Inst. 36, 169 (1940i

5. There was no significant diirereiice in the

permeability of brick walls hi wliich mortar for

th(^ bed pints was leveled or furrowed before

placing the bricks, suthcient mortar having

been used to cover the bed.

6. Brick walls, 8-in. thick, containing cored

bricks and in which the vertical joints were

completely filled, were highly resistant to water

penetration and were sUghtly but significantly

less ])erm cable than similar walls built of solid bricks.

7. The least periaeable brick walls were

built of units having a low brick-suction. Eightinch brick walls hi which the vertical joints were completely filled, were rated as "good" or "excellent" when the brick suction did not

exceed 10 g. Twelve-inch walls, with filled vertical joints, were rated as "good" when the

brick-suction averaged about 20 g. Similar

walls were highly permeable if the brick-suction

exceeded 50 or 60 g, particularly when built

with a mortar having a low- water retentivity.

8. Low-absorptive bricks or those in which

the "suction" was greatly reduced by pre- wetting, but which did not contain excessive

amounts of absorbed water, were laid without

difficulty in a mortar of high water retentivity.

Wlien such bricks wei'e used with a mortar of

low water retentivity, the construction of the

walls was marked by excessive bleeding or by

extrusion of the mortar from the joints. However, the walls so constructed were highly

resistant to water penetration.

9. When the bricks had a high suction and

were laid in a mortar having a low water retentivity, the walls were difficult to build and they were also more permeable than if a mortar

having a high water retentivity was used.

10. Twelve-inch walls faced with brick and

backed with hollow units were more permeable

than similar all-brick walls. The kind of hollow^ unit used in the backing had no consistent or important effect on permeability, but the walls

containing the end-bearing units appeared to be

slightly less permeable than those containing

side-bearing hollow units.

11. Walls of concrete units, without protective facings or coatings, were highly permeable.

Washington, January 23, 1942.

137]

BUILDING MATERIALS AND STRUCTURES REPORTS

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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 100 BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 100 BMS4 Accelerated Aging of Fiber Building Boards 100 BMS5 Structural Properties of Six Masonry Wall Constructions 150 BMS6 Survey of Roofing Materials in the Southeastern States 150 BMS7 Water Permeability of Masonry Walls 100 BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 100 BMS9 Structural Properties of the Insulated Steel Construction Co.'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 Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 100 BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 150 BMSl3 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

WheeUng 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 Supplement to BMS17, Sound Insulation of WaU and Floor Constructions 50 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 100 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co 150 BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block Wall Construction Sponsored by the National Concrete Masonry Association. 100

[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.. lOfS BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors, Sponsored by Palisade Homes lOjS BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co lOji BMS39 Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co 10j5 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 15(4 BMS43 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 Tile- crete Co 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 BMS56 A Survey of Humidities in Residences 100 BMS57 Roofing in the United States: Results of a Questionnaire 100 BMS58 Strength of Soft-Soldered Joints in Copper Tubing 100 BMS59 Properties of Adhesives for Floor Coverings 100 BMS60 Strength, Absorption, and Resistance to Laboratory Freezing and Thawing of Building

Bricks Produced in the United States 150 BMS61 Structural Properties of Two Nonreinforced Monolithic Concrete Wall Constructions 100 BMS62 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by the Portland Cement Association 100 BMS63 Moisture Condensation in Building Walls 100 BMS64 Solar Heating of Various Surfaces 100 BMS65 Methods of Estimating Loads in Plumbing Svstems 100 BMS66 Plumbing Manual 1 200 BMS67 Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by Herman A. Mugler 150 BMS68 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 3 150 BMS69 Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 100 BMS70 Asphalt-Prepared Roll Roofings and Shingles 150 BMS71 Fire Tests of Wood- and Metal-Framed Partitions 200

BMS72 Structural Properties of "Precision-Built, Jr." Prefabricated Wood-Frame Wall Construction Sponsored by the Homasote Co 100 BMS73 Indentation Characteristics of Floor Coverings 100 BMS74 Structural and Heat-Transfer Properties of "U. S. S. Panelbilt" Prefabricated Sheet-Steel Constructions for Walls, Partitions, and Roofs Sponsored by the Tennessee Coal, Iron & Railroad Co 150 BMS75 Survey of Roofing Materials in the North Central States 150 BMS76 Effect of Outdoor Exposure on the Water Permeability of Masonry Walls 150 BMS77 Properties and Performance of Fiber Tile Boards lOi

BMS78 Structural, Heat-Transfer, and Water-Permeability Properties of Five Earth-Wall Constructions 200 BMS79 Water-Distributing Systems for Buildings 150 BMS80 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 4 150 BMS81 Field Inspectors' Check List for Building Constructions (cloth cover; size, 5 by 7 inches)... 200 BMS82 Water Permeability of Walls Built of Masonry Units 200