Bureau of Standards

1 » .
The program of research on building materials and structures undertaken by the

National Bureau of Standards is planned with the assistance of the following advisory

committee designated by the Subcommittee on Design and Construction of the Central

Housing Committee.

TECHNICAL RESEARCH GROUP

Walter Junge, Federal Housing Administration, Acting Chairman

A. G. Bear,

Veterans' Administration.

Pierre Blouke,

Hoine Owners' Loan Corporation.

C. W. Chamberlain,

Procurement Division.

Jos. M. DallaValle,

Public Health Service.

Hugh L. Drtden,

National Bureau of Standards.

G. E. Knox,

Bureau of Yards and Docks, Navy

Department.

Charles E. Matette,

United States Housing Authority.

Vincent B. Phelan,

National Bureau of Standards.

E. A. POYNTON,

Bureau of Indian Affairs.

John H. Schaefer,

Procurement Division.

A. C. Shire,

United States Housing Authority.

George W. Trater,

United States Forest Service.

Elsmere J. Walters,

Quartermaster Corps, War Depart

ment.

Sterling R. March,

Secretary.

The program is administered and coordinated by the following staff committee of

the Bureau.

Hugh L. Dryden, Chairman

P. H. Bates W. E. Emley A. S. McAllister

H. C. Dickinson G. E. F. Lundell H. S. Rawdon

The Forest Products Laboratory of the United States Department of Agriculture

is cooperating with the National Bureau of Standards in studies of wood constructions.

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UNITED STATES DEPARTMENT OF COMMERCE • ]3aniel C. Roptr, Secretary

NATIONAL BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS7

Water Permeability

of Masonry Walls

by CYRUS C. FISHBURN, DAVID WATSTEIN, a?ld

DOUGLAS E. PARSONS

ISSUED October 18, 1938

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

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

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE 10 CENTS
c

Foreword

When the wall of a house exposed to wind-driven rains allows dampness to penetrate

to the interior, damage to the interior finish may be sufficient to require its replacement,

a matter of considerable expense. Accordingly, there is great interest on the part of

builder and owner in methods of constructing walls which wUl be resistant to the penetration of rain and in methods of "waterproofing" existing walls. An extensive investigation of the rain penetration of masonry construction is in progress at the request of

and in cooperation with numerous Federal agencies. This paper gives the results obtained to date.

Because of the many kinds and qualities of masonry materials and varieties of

design, and the lack of a definite measure of the performance of a wall with respect to rain penetration, the study must be very comprehensive, and the results cannot be

adequately summarized in a few words. Of the many factors, worlcmanship is the most

important single one. However, attention to many other factors will assist greatly

in securing good results. Existing walls may be effectively "waterproofed", but the

cost and success of the treatment depend on many factors discussed in detail in this paper.

Lyman J. Briggs, Director.
Water Permeability of Masonry Walls

by CYRUS C. FISHBURN, DAVID WATSTEIN, and DOUGLAS E. PARSONS

CONTENTS

Page

Foreword II

I. Introduction 2

II. Scope of investigation 3

III. Masonry walls 3

1. Materials 3

(a) Bricks 3

(b) Structural clay tiles

and hollow concrete units 3

(c) Mortars 5

(d) Stucco 6

2. Types and designations of walls 6

3. Method of construction 7

4. Workmanship 10

(a) Class A 10

(b) Class B 10

(c) Class C 11

(d) Class D 11

(e) Class E 11

5. Aging 11 IV. Method of testing permeability of walls 11

1. Capillarity test 12

2. Heavy-rain test 12

3. Light-rain test 12

V. Rating of performance 12

1. Observations 12

(a) Time required for penetration 12

(b) Rate of leakage 13

(c) Appearance of wall during and after

test 13

2. Arbitrary ratings 13

VI. Performance of walls 14

1. Consistency of results 14

2. Effect of variation in methods

of testing 14

(a) Comparison of capillarity and heavyrain tests 14

(b) Comparison of lightand heavy-rain

tests 14

VII. F,ffect of kinds of workmanship or materials used in walls of brick masonry 14

1. Comparison of workmanship. 14

2. Effect of wall thickness and

kind of brick 15

3. Effect of absorptive backing. 16

Page

4. Comparison of mortars 17

(a) Effect of varying per- centages of lime and

cement in mortars

of high water re- tentivity 17

(b) Effect of using a mortar of low water

retentivity 18

5. Effect of brick suction 19

6. Effect of using blind headers. 20

7. Effect of mortar parging on

brick facing 20

8. Effect of a stone belt course. - 21

VIII. Effect of workmanship and materials in walls containing hollow masonry building

units 21

1. Walls with structural clay tile backing 21

2. Walls with backing of hoUow

concrete units 22

3. Stucco facing on structural

clay tile 22 IX. Surface waterproofing treatments. 23

1. Repointing of face joints 24

2. Paraffin and tung-oil solution. 24

3. Joint filling 26-

(a) Waxed joints 27"

(b) Grouted joints 28-

4. Special proprietary treat- ments 28-

5. Aluminum-stearate solution. 29-

6. Linseed-soil solution 30'

7. Molten paraffin 30-

8. Paints 30-

(a) Oil paint 30'

(b) Cement paint 31 X. Summary 32:

1. Definitions 32:

2. Conclusions 32 XI. Appendix—Review of previous in- vestigations 33'-

1. Tests at Mellon Institute... 33

2. Tests at the National Bureau

of Standards 33

3. Tests of the Louisville Ce- ment Companj- 34

4. Tests of the Alton Brick Company 34

5. Tests of the Portland Cement

Association 34

[1]
ABSTRACT

Walls of brick, structural clay tile and hollow concrete unit masonry were tested under conditions resembling exposures to wind and rain and their resistance to the penetration of water determined. Five kinds of workmanship (method of filling joints), three kinds of

brick, six kinds of structural clay tile, two kinds of hol- low concrete units, and six different mortars were used

in the construction of the walls. One group of 48 brick

walls included specimens, both 8 and 12 inches thick, of three kinds of brick, four cement-lime mortars, and two

classes of workmanship, in aU possible combinations.

The walls of structural clay tile were faced either with

stucco or with brick of a single variety. Those of concrete units were faced either with the same brick or with cement paint. The effectiveness of several methods of "waterproofing" were compared by retesting some of the

walls after they had been treated. The treatments for the walls included the filling of openings in the face

joints with mortar, grout, or wax and the application to the exposed surfaces of colorless solutions or paints.

Most of the walls were subjected to water penetration

tests under two dififerent conditions. Water was applied near the tops of the waUs in a manner to produce a thin film of water over their exposed surfaces. In the

"capillarity" test no pressure was applied to the exposed

face, the water penetrating under the forces of capillarity and gravity only. In the "heavy-rain" test a static

air pressure of 10 pounds per square foot was maintained against the exposed face. The performances of the walls in the water penetration

tests depended more upon the quality of the workmanship than upon any other factor. WaUs of brick having the interior joints well filled with mortar usually

gave excellent performances, whereas those with poorly

filled joints leaked. Aids in obtaining walls resistant to moisture penetration were the use of mortars of medium

or high water retentivity, the wetting of absorptive

brick before use, and the application of a parging of mortar on the back of the facing wythe. The omission

of two-thirds of the normal number of header brick, or the insertion of a limestone sill or belt course had no

important effect on the permeability of the walls. On

the average, walls with a brick facing and a backing of hollow masonry units were shghtly less permeable than

brick walls of equal thickness when the joints were not

well filled. When the joints were well filled the per- formance of walls with hoUow units was somewhat su- perior in the capillarity test but inferior in the heavyTain test to that for otherwise similar all-brick waUs. The performances of walls of structural clay tile faced with portland-cement stucco was somewhat better than

the average for the walls of brick. The filling of openings in the joints with mortar, grout, or wax was effec- tive in stopping leakage. Applications of colorless waterproofing solutions did not stop leakage througli

openings in the joints, but were effective in improving

the performance of walls of absorptive brick when the openings in the joints had been sealed. Coatings of molten paraffin, oil paint, and cement paint were effec- tive in reducing moisture penetration.

I. INTRODUCTION | Many exterior masonry walls of buildings are giving excellent protection against the penetra-,

tion of water, and artisans are familiar with the

technique of such construction. However, there

is little published information on the relative

effectiveness of walls differing as to design, mai

terials, and workmansliip which would serve as a basis for the preparation of technical specifications. Reported observations on the perform- ance of walls in buildings have given but little specific information. Since many kinds of masonry materials and varieties of design are in use and as there are considerable differences in

the severity of exposure even in a single locality,

quaUfied observers have not always been in agreement as to the relative importance of fac- tors contributing to watertight walls. With the

object in view of determining the relative merits of several types of masonry construction by

building and testing walls, the Bureau of Yards

and Docks, Navy Department, with the cooperation of other governmental agencies, spon-l

sored an investigation at the National Bureau

of Standards.

The original program was prepared with the

assistance of representatives of the Bureau off Yards and Docks, the Procurement Division,

the Quartermaster Corps, War Department,

and the Housing Division, Federal Emergency

Administration of Public Works, and those

agencies transferred fimds to assist in defraying the cost of the work. When funds from the

Emergency Relief Act were allotted to the National Bureau of Standards for research on the

durability of materials for housing, members of the Subconmiittee on Design and Construction

of the Central Housing Committee sponsored a program of research requiring the construction

and testing of additional walls. This program

called for tests of types of construction not' included in the original program. Investiga-J

tions of waterproofimg treatments for masonry l' walls were also included. Inasmuch as the

materials and the methods of constructing and

testing the walls were the same for both pro-'' grams, and as the results are of most value

'

when considered collectively, no distinction'' between the programs will be made in this re-

^

port. "

[2]
II. SCOPE OF INVESTIGATION

The investigation was planned to obtain

information on the effects of the following

factors on the permeability of masonry walls:

(a) Tliickness, bonding of units, kind of brick

or hollow unit, kind of mortar, and method of

filling joints.

(b) Wind pressure on walls.

(c) Repointing and waterproofing treat- ments. Five kinds of workmanship (method of filling

joints), 3 kinds of brick, 6 types of structural

clay tile, 2 kinds of concrete units, and 6 differ- ent mortars were used in the construction of

113 walls. One group of 48 brick walls in- cluded specimens both 8 and 12 in. thick of

3 kinds of brick, 4 cement-lime mortars, and

2 classes of workmanship in all possible combinations. The walls of structural clay tile were

faced either with stucco or with brick of a

single variety (brick b) ; those of concrete units were faced either with the same brick (brick b) or with cement paint. All walls of hollow

masonry units were built with a single cementlime mortar.

III. MASONRY WALLS

1. Materials

All of the materials used in the construction

of the walls were representative of those com- monly used in building construction and were

purchased from either the makers or building

supply dealers. The purchases were usually

made on a noncompetitive basis in order that a selection of materials could be made to meet

the special requirements of the investigation.

(a) Bricks

The bricks were selected to cover a wide

range in both the rate and amount of absorption for bricks used in exposed structures. The physical properties of the bricks are given

in table 1. One type of brick had a very low, one a medium, and the third a very high and rapid

absorption. The low-absorptive brick, designated as brick a, was a side-cut fire-clay brick,

light in color with a slight fire gloss on edges

and ends. The medium-absorptive brick, brick

b, was a side-cut shale brick, selected hardburned, dark brown in color, and somewhat

irregular in shape. The high-absorptive

brick, c, was red dry-press brick with a high

rate of absorption, selected by eliminating the

harder-burned specimens.

Table 1.Physical properties of bricks

Properties of briclcs

(Width

Average dimension (in.) -(Length iDepth

Average dry weight (lb.) _ {.5-hour cold_.- 48-hour cold, C.

5-hour boil, B.. C/B ratio..

.\bsorption by partial immersion

(g of water per cm 2 of brick sur-i face)

Flat I /I min.

"13 min.

^"^'^--\3 min..

T,„, /I min.

''^°<^- - - l3 min_. Time required for total penetration by cap-JEIf*"

illary action (hr.) Modulus of rupture (lb/in.*)... Compressive strength of half-bricks (Ib./in.^).

Types of brick

3.75

8. 00

2.25

5. 21 0.4

2,460

16, 900

3.60

7. 75

2. 15

4. 35

7. 7

9. 1 11.4

0. 80

.19

. 14 .23

. 12 .22 .40

1.9

12.5

1, 180

7, 580

3.95

8. 20

2. 30

4.76

15,9

16.8

18.8

0. 89

.61 1.10

.69

1.18 .70

1.18

0. 12 .32

1.8250

2, 370

1 Absorption in grams per brick approximately 200 times these values. The data of table 1 shows that brick a is dense, hard, and practically impermeable, with

very little absorption or suction. Brick c had

a very high rate of absorption. This brick

absorbed 35 percent as much water when partially immersed on the flat face for 1 minute as

it did when totally immersed for 48 hours.

The absorptive properties of brick b were

intermediate between those of a and c.

(6) Structural Clay Tiles and Hollow Concrete Units

The physical properties of the structural

clay tiles and of the hollow concrete building

units are given in table 2. Six different types of structural clay tile and one kind each of stone and cinder-concrete block are described in the

table. The details of the units are illustrated

in figure 1. The rate and total of absorption

for tiles g and h are about double the average

values for the other four structural clay tUes. Although the total absorption for the 24-hour

cold-water immersion of the cinder-concrete

units was nearly double that of the stone-concrete block, the rate of absorption was much less.

[3]
6"and 12-

K IZg - ^ K -5 >1

eS/de Co/7s/rac//on 77/e {header j Aarc/cer)

- 12- ^ k .5--.-..H

e/-£)oo6/e SM/Tz/e r/teac/er s Sc/cAerJ

n-C//7c/€r Concrete B/ocA

K-T-6?---^lBk

t- 6"and 12-1

/- Speed-a- AarcAer W/e

i-

-le

: M

.J I

tVJ

J-Sfandorrcf T//e fend and s/de cons/roc^/ofi)

low

' 1

'<! ,«

If

. J. ..^

la QUO

^

rIll------ ->

> -i'-J.

v'- 1

: . i : H - - '

i"*^ . f

:

. 1 -

. -1

1. t

- r

; 1 . "•:.'J - <..•"!

1 1 ..

/» - iS/one Cbncrv^ B/ocA

I 4" H

.'WIS

lOleo

ff~/iarf///e CAeaa^e/- <* AacAer-J

r-2rl+2if 2i|-T H2i^

A-TechvvoodWe CAeader* AacAerJ

Figure 1.

Details of structural clay tiles and hollow concrete units.

[4]
Table 2.

Physical properties of structural clay tiles and hollow concrete building units

Masonry unit Exterior dimensions

Thickness

of

face

shell

Dry

weight

Absorption by 24-hour

cold immersion

Absorption by

1-hour DOU

Weight

per ft.

3

of concrete

Weight

per

ft.»of wall

face area

Compressive

strength Face .shell immersed in H-inch of water

Desig- nation

N"anie Thickness Width Length Net

area Gross

area

Absorption, g per em 2

face

(3 min)

Capillary

rise of water

in

first hour

Time re- quired for capillary

rise through

tile

in. in. in. ID % lblft.3 Of70 10 10 Ib/in.'' tbiin.i % in. in. hr

d Double-shell, 6 cells. 8.0 12.

1

10. 45 0. 5 33. 3 2.8 3. 9 37.

9

H,970 4, 830 0.01 1.7 8 23

e Side construction, 7.9 5.0 12.0 15. 8 5.7 8.

1

38.

0

1,760 .05 1.0 6.5 168

3 cells.

f Speed-a-backer - 7.8 7.7 12.0 . 65 22. 5 4. 1 7.1 38.7 1,820 C) 1.0 4.4

8

168

g Raritile, i cells 7. 85 12.0 7.9 1.0 25.8 10.6 14.6 39.4 8. 010 3, 290 . 13 2.4 8.5

ft Techwood, 6 cells... 7. 75 11.85 9.9 1. 25 33. 7 10.4 13.3 41.3 7,610 3, 180 . 11 1.9 8 12

j Standard, 6 cells 8.0 12.

1

12.0 0. 75 34. 1 4.

1

6.3 34.0 7, 890 2, 870 .03 2. 3 m Stone-concrete 7.8 11.75 7. S5 1. 5 29.9 8.9 10.8 121.4 46. 7 2, 410 790 .75 3. 1 8 86

blocks, 2 cells. n . . Cinder-concrete 8. 05 11.8 7. 55 1.8 21.9 16. 2 13.3 82.2 35.2 2,430 870 . 14 1.0 3.3 168 blocks, 2 cells.

' Negligible.

(c) Mortars

The six mortars used in the construction of

the walls were designed to determine the

relative permeability of walls built with liighlime or high-cement mortars, the effect on

permeability of integral w^aterproofing and of

differences in water-retaining capacity. The

physical properties of these mortars are given

in table 3. Mortars 1 to 3 differ in the relative

percentage of lime and portland cement.

The lime used in these mortars was a fast- slaking pulverized quicklime with a plasticity ^

of over 600. Mortar 5 contained a selected

lime hydrate with a plasticity of only 110. The water content of all the mortars was

adjusted to the satisfaction of the mason, and

it usually varied with the kind of brick used.

A variation of 1 percent in the water contents

given in table 3 for the first four mortars had

apparently little effect on the workabihty so that mortar remaining after using one kind of brick was often used to start a similar wall of

another kind of brick. All mortar materials were proportioned by weight and mixed in a batch mixer of about %-cubic-foot capacity.

Table 3.Physical properties of mortars

Properties of mortars Brick

Mortars numbers and proportions

1 2 3

a 4 t 5

1:0.25:3 1:0.11:2.6

19.3 19.3

19.3

1:1:6

1:0. 42:5.

1

21.4

22.9

23.4

1:2:9

1:0. 85:7.7

23.0 23.8

24.4

1:1:6

1:0. 42:5.1

22.

1

22.6

23.3

1:1:6

1:0. 42:5.1

18.0

19.8 21.6

19.3 22.6 23.7 22.7 19.8

2, 850

2, 850

2, 850

725

625

575

265

250

230

565

495

525

1, 195 885

780

2, 850 640 250 530 950

8786

10495

10997105

95

49

30

Proportions of cement, lime, and sand dryw'^ight

.\verage water content, percentage by weight of dry materials

.Average

Compressive strength in 28 days (Ib/in.2) ^

.Average.

Flow after 1 min of suction on porous base (Dercentagejo-.jj^jf!!} Jjq^"

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

t Mortar 5 contained hydrated lime of low plasticity, which was added to the mortar in dry state; all other mortars contained highly plastic lime putty

prepared from pulverized quicklime.

» Proportioning was by weight, assuming portland cement weighs 94 Ib/ft^, dry hydrated lime, 40 lb/ft', and that 1 ft' of loose damp sand contains

80 lb of dry sand.

* Cured according to Federal Specification SS-C-181.

<^ Test for initial flow of 130 percent; described in Rock Products, September 10. 1932, "Rate of Stiffening of Mortars," by L. .\. Palmer and D. A.

Parsons; Test for initial flow of 110 percent. Federal Specification SS-C-181a.

1 Plasticity determined according to Federal Specification SS-L-351. The lime used in mortars 1 to 4, inclusive, was lime .4 and that used in mortar 5 was lime C—described in J. Research NBS 17, 895 (1936) RP952. (See fig. 7.)

[5]
The sieve analysis of the Potomac River

building sand used in the mortars is given

below:

Si6V6 Duinb6r Weight of sand

passing

Percent 4 100. 0

8 99. 4

16 94. 4 30 75. 2 50 14. 0 100 1. 0 200 0. 5

{d) Stucco

The stucco facing for the eight walls of tile j was mixed in the proportions by weight of 1 part of Portland cement to 3 parts of dry sand

;

volume proportions were 1 part cement to about 3.5 parts of loose damp sand. The

stucco applied to four of the eight walls contained a conmierical ammonium stearate amounting to 0.2 percent by weight of the

cement. The water added to each batch was

suitable to the mason and amounted to about

18.7 percent by weight of the dry materials or

8.5 gallons per sack of cement. After the stucco

5ecfion on "B-B

"

^T-Morfarparging on ends and fop ofira//-

'•, ' • -38 'appmx

DC

DC cuaacDczirjiZ]

Rear E/et^af/on Figure 2.

3fand Channe/

Secfion on "/i-A" Rear elevation and sections of a typical brick masonry wall.

Figure 3.

Isometric projections of walls with brick facings and backings of hollow units, workmanship A.

d, double-siiell tile; e, side construction tile; /, Speed-a-backer tile, and Raritile.

was applied to the walls, they were thoroughly

wetted each day for several days.

2. Types and Designations of Walls

The walls of all-brick masonry were of four

different types of workmanship, described in

section III (4) (pages 10, 11) and designated as A, B, C, and D. Walls containing other kinds

of masonry units were constructed of workmanships A, B, or E. All of the walls are

listed by number and described by designation

in table 4 which also gives data showing per- formance under the tests. In the first column

of table 4 the first number of the wall gives its serial location in the table. The second number, given the wall when it was constructed, is

[6]
the number listed on all original data sheets. In the discussion of a wall in this report, both

numbers will be given.

3. Method of Construction

Details of the construction of some of the

walls are shown in figures 2, 3, and 4. Separate bids were asked for the construction of the walls in two consecutive groups, and

the same contractor was the successful bidder

for both contracts. The work was performed

by experienced masons and both the contractor and his workmen cooperated wholeheartedly in

meeting the specification requirements.

Figure 4.Isometric projections of walls with backings

of hollow units, workmanship A.

h, Techwood tile; n, cinder-conerete block; j, 8- by 12- by 12-in. tile showing end and side construction (stucco facing not shown)

.

Table 4.Performance of masonry walls in 'permeability

tests KEY

Lower case letters denote brick or other structural unit. The first letter in designation shows the material used in facing w ythe. Arabic numerals show either nominal wall thickne.'-s in inches, or the mortar number when used in later sequence.

Capital letters shew workmanship. a= Brick a (low absorptive). b = Brick 6 (medium absorptive). c=Brick e (high absorptive). d = Double-shell tile. e=Side construction tile. f=Speed-a-backer tile. g = Raritile. h = Techwood tile.

i =8X12X12". m= Stone concrete block. n= Cinder-concrete block. p = Mortar parging.

s = Stucco.

Wall Designation " Duration of

test !>

Time to fail as indicated byRating b Damp

through

wall

Leak

through

wall

Leak

through

facing *>

Walls of Common American Bond

1-15

2-77

3-65

4-56

5-74

6-42

7-16

8-64

9-55

10-48

11-68

12-69

13-14

14-60

15-58

16-51

17-92

18-17

19-61

20-57

21- 47

22-18

2.3-Al

24-A7

aal2Al

Days

f 14

I 14

{ ]

f 7

I 8

f 5

I 4

Hours Hours Hours E

E

E

E

E

E

E

G

aal2Al

aal2A2 .

aal2A3

84 aal2A3 <

aal2A4

\ 4

f 7

I 7

f 1 \ 1

f 1 \ 1

( 1

{ 1

1. 1

/ 2

I 1

I 7

f 1 \ 1

f 14

I 6

/ 3

I 3

/ 2

1 1

f 2

I 1

f 1 1 1

/ 1 1 1

f 1

I 1

( 0.8

{ 1

I 1

r 2

I 0.2

f 4

1 0.8

f ^

I 7

65 E

E

E

P

VP

P

P

P

P

F

P

VP

E

GFP

E

E

G

G

GG

G

GGFVP

VP

P

VP

P

VP

FP

VP

G

G

GGE

E

aal2B2

0.9

. 1 1.9

2. 2 2.2

1 122.6 0.17

2.6

0.1

0. 05

.15

.1

. 03

.2.07 5.5

0. 05

.05

aal2B3

aal2B4

15

aal2C2

412.8

4 192

13467

58

31

5

18

0. 37

1712.5 0.08

.03 .37

.05

.25

.1 9

0. 04

.04

504.5

41

13. 5 41

43

aal2D2 2.8 0.45 aaSAl

aa8A2

aa8A3

aa8A4

aa8Bl

aa8B2

aa8B3

aa8B4

bbl2Al

0.08

.03

.78

.32

.25

. 1 18.1

0 04

.04

0.03

.08

.12

.04

.07

.03

9

0. 12 .04

bbl2Al

bbl2Al

See footnotes at end of table.

90694° —38 2 [7]
Table 4.

Performance of masonry walls in permeability

tests—Continued

[For key see p. 7]

DuraTime to fail as indicated byRat- Wall ing t Designation ^ tion of

test b Damp

through

wall

Leak

through

wall t

Leak

through

facing t

Walls of Common American Bond—Continued

Bays Hours IIn UTS Hours G

bbl2A2 ! 5 26 25-27

\ 1 1 G

26-A4 bbl2A2 /

1 10. 5 G

I 6 18 G

( I 15 G

27-Afi bbl2A2 I

1 9.5 G

J 19

17 Q

1 1 G

28-73 bbl2A3 \ 1 12.5 G

[ 1 20 G

on A o bbl2Ao f 2 29 G

1 2 41 G

30-45 bbl2A4 r 5 30

0. 6 82 G

\ 1

ri

31-72 bbl2Bl

. 33

. 03 13.5

0. 07

0, 07

. 02 VP

1

'

p

1 1 6 15 15 p

32-50 KK1 OTIQ r 1 0. 45

. 10 2.50. 13 0.8.05 pVP

33-19' bbl2B3 .23

. 03

.35

. 03

1. 5

0. 03 VP

34-4n

5. 2

0. 12 140. 12 .03 .02 p

I

1 VP

35-62

r 1 .03

.01

. 20

.05

.01

1. 2

0. 25 FVP

F

\ 1

36-53 bb8A2 1 I .02 .08 F

I. 5 F

37-59 bb8A3 ____

1 1

J 1

0. 03

.02

18

0. 05

184.5 F

F

i 1 2.5 3.5 F

38-49 bbSA4

{ 1 3. 5 F

\ 1 0. 05 0. 05 0. 38 VP

39-63 bbSBl

f 1 .05 .02

.805.0303 VP

VP

40-22 bb8B2

1 0.8

<

. 1305.42 .30

13 VP

VP

\ 1 5. 7 F

41-A9 bb8B2. .

c 1 0. 02

.02

. 10 .02 .37

.02 VP

\ 1 VP

42-AlO bb8B2 „ r .03

. 02

.05

. 02

. 10

. 02 VPVP

3 14. 5 4. 5 F

43-54 hb8B3

r 1 0. 03

. 03

0. 17

. 07

0. 05

. 05 VP

44-52 bDSB4 - r 1

1 0.9

.03

.01

',S

.03

.01

. 17 .03 FVP

E

45-28 CC12A1 6. 5 15 F

11 G

3. 5 G

46-76 crl2Al 0.08 F

9 F

47-9!' Cfl2Al 3S

11 G

G

48-AS ccl2Al__

20 G

9 G

49-35 CC12A2

21 G

7.3 G

GF

50-06 CC12A2 = 12

( 0.6 0. 13 1.3 2.3

51-33 CC12A3 / 2

I 1 208 G

G

24 G

52-75 CC12A3 1

! 4.6 G

13. 5 G

Table 4.^

Performance of inasonry walls in permeability

tests—Continued

[ For key see p. 7]

53^3

54-A17

55-A19

56-29

57-37

58-67

59-21

60-44

61-A13

62-A20

63-71

65-31

66-36

67-20

68-40

69-30

70-34

71-32

72-41

DuraTime to fail as indicated byRating b Wall Designation " tion of

lest I' Damp

through

wall ^

Leak

through

wall b

Leak

through

facing b

Walls of Common American Bond—Continued

ccl2A4_.

CC12A5-.

CC12A5 '

CC12B1..

ccl2B2_.

CC12B2 <

CC12B3..

ccl2B4_.

ccl2B5_.

ecl2B5 <

CC12C2..

ccl2D2_

cc8Al_

cc8A2_.

ec8A3..

ec8A4..

cc8Bl..

CC8B2..

CC8B3..

CC8B4..

Days

2

1

• 1

0.9

11

11

10.9

11

1

0. 2

11

1

1

1

1

1

1

1

1

1

1

1

1

120.2

11

0. 2

. 1 10.2

. 2

1

0. 1

1

20.2

Hours

9

1

5.

1

0. 23 1.2

0. 42

.37

. 17

190,53

.02

13, 7

0. 97

1515

2

0, 50 1,9

0, 27

,42 ,05

2

0. 37

9

1. 7

0. 25

18

0.9

.47

4

0. 45

. 25

1

0. 75

. 17

. 10 5.5

0. 13 .03

. 22

. 15

5. 5

0. 20 .05

Hours

~~'i.~5~

0. 75

140.8

3.7

3

0. 35

1.6

0. 12

1. 1 0. 10

15

0. 45

72.8 0.48

1. 5

0. U

.50

.05

3. 6

0. 22

14. 5 2

0. 05

Hours

14.5

30.2

. 13

19

0. 13

. 13

3, 5

0. 25 .50

,23 .20

,30

, 10

.58

0. 45

7

2.3

0. 22

. 15 15

33.5

0. 36 .28

14. 5

0. 07

. 12

Brick Walls With Two-Third "Blind" Headers

7.3-89

74-90

75-38

76-88

77-91

78-39

aa8A2.

bb8A2_

cc8A2_.

aa8B2.

.

bb8B2.

CC8B2,.

3 60 G

2 43 G

1 0. 53 F

1 .03 F

1 4 F

0.8 0. 92 5.8 F

1 .25 0. 38 4. 5 VP

0.9

. 1 .07.02

.07 .02

0. 15 .03 VP

VP

1

1 .03

.03

.07

.03 .07

.03 VP

VP

10. 2 .22 .08

15

0. 18 .33. 18 pVP

See footnotes at end of table. See footnote.? at end of table.

[8]
Tabi.e 4.

Performance of masonry walls in fenneahilitij

tests—Continued

[For key see p. 7]

4-inch Brick Walls With Parged Backing

83-A13 ap4Al

84-A15 ap4Alw.

85-A14 cp4Al --

86-A16 cp4Alw.

{ I

9

0. 88

1.2 0.22

.35

.38

310.83

1. 5 310.83

AValls With Structural Clay Tile Backing

87-9 bdl2A2 d

88-11 bel2A2

89-12 bfl2A2 d

90-82 bgl2A2. -

91-26 bhl2B2'l

92-13 bdl2B2<i

93-83 bgl2B2

94-23 bhl2E2'i

9.5-25 bhl2E2 d

96-10 bdl2E2 d

14 96

1 2.5

1 20

6 65

1 9 2 11.5

1 0.50

1 9.5

1 0. 05

2 20

1 0.22

1 3

1 0.38

1 .92

1 .20

6 72

2 9

4 96

2 17 117

4 60

0. 75 4

7

0. 05

.07

.13

. 12 .10

.03

41

0. 22

20

Stucco Walls With Clay Tile Backing

97-1 sj9A2 d

98-2 sj9A2 d

99-3 sj9A2 d

WO-A sj9A2 d

101-5 S59A2 d

102-6 sj9A2 d

103-7 sj9A2 d

8 168

5 89

5 60

3 41

14

14 209

14

6 65

14

6 108

5 65 132

14

7 132

Wall Designation " Duration of

test

Time to fail as indicated byRating b Damp

through

wall b

Leak

through

wall ^

Leak

through

facing i>

WaUs With Stone Belt Course

79-84

80-85

aal2A2 —

Days

{ I

{ I

Hours

26

26

24

9

Hours Hours G

G

G

G

bbl2A2

41

Walls With High-Absorptive Brick Backing

81-86

82-87

ac8A2

{ I

{ \

14489

0. 17 .05 3.5

E

GP

VP

G

ac8B2

15

0. 83

0. 90

.33

E

6

GE

G

GF

6

F

VP

^-p p

p

VP

VP

GGG

GE

G

E

6

G

GE

E

E

GE

E

E

E

E

E

T.\BLE 4.

Performance of masonry walls in permeahilily

tests—Continued

[For key see p. 7]

Wall Designation « Duration of

test i>

Time to fail as indicated byRating b Damp

through

wall b

Leak

through

wall b

Leak

through

facing b

Stucco Walls With Clay Tile Backing— Continued

104-8

Days

{ u

Hours Hours Hours E si9A2 G, E

d

(«) (•) («)

Walls Containing Hollow Concrete Units

105-80

106-A3

107-A5

108-78

109-93

110-A12 lU-AU

112-81

113-79

bml2A2.

bnil2A2_

bml2A2_

bnl2A2_.

bnl2A2.. m8A2 d_.

n8A2 d__.

bml2B2_

bnl2B2__

1 0. 85 4 5 F

1 . 17 0.77 P

2 5 G

1 2.3 5.5 F

1 6.5 G

1 1.3 8 F

2 6 G

1 0. 13 0.58 F

E

3 50 G

1 0. 03 6.5 .08 VP

1 .02 0. 02 .02 VP

1 .03 .08 VP

.05 .05 VP

0.2 .37 .05 VP

.07 .03 VP

0.2 .27 .08 VP

.08 .08 .03 VP

See footnotes at end of table.

a See "Key" at top of table.

b Results of capillarity, heavy-rain, and light-rain tests for each wall

are given, respeotively, in the first, second, and third lines.

" Brick were dry when laid. Capillarity test not completed after 2 days.

J Wall not flashed at bottom.

•> Heavy-rain test on wall 104-8 not completed after 5 days.

' Constructed in place of wall 46-76. The absorption of the bricks during a partial

immersion for 1 mmute on the fiat side in ]i inch of water was limited to a maximum of 50

grams. It was necessary, therefore, to reduce

the suction of brick c by totally immersing

them in water for about 1 minute or more, depending upon their condition when received

from the storage pile. Brick a were dried

before laying. Figure 2 shows a rear elevation

and two sections through a typical brick masonry wall. Common American bond consisting

of five stretcher courses and a header course was used in the walls of brick masonry. The

thickness of the joints ranged from % to % inch.

The two flashmgs shown in figure 2 were placed

at the bottom of the brick walls to catch leakage.

Some of the walls of hoUow building units were

not flashed. Others contained a single flashing

similar to the lower one shown in figure 2. A

mortar parging % inch thick was applied on

each end and on top of all waUs in order to pre-

[9]
vent the escape of appreciable quantities of air or water through these surfaces during a test; so that, when pressure was applied to the ex- posed face, a pressure gradient would be maintained through the thickness of the wall.

4. Workmanship

Of the five different kinds of workmansliip

used in the construction of the walls, the masons

were most famihar with classes B and D. The

other classes required more effort, but as the

building of the walls continued, less time was

required for satisfactory work. The different

kinds of workmanship were as follows (not

listed in sequence of quality):

Figure 5. —Wall Hi -'il (miSA/f) during construction,

illustrating workmanship A.

a, front view before tooling face joints, and b, back view showing

solidly filled cross and collar joints.

(a) Class A

Figure 5 illustrates class A workmanship.

All joints were filled with mortar. The bed

joints were spread to a uniform thiclmess (not

furrowed). The cross or head joints were filled by applying mortar to the ends of stretchers

and the sides of headers, the mortar being

applied before the brick were laid by scraping

the trowel on their lower edges. After laying

the brick in each course, the filling of cross

jouits was completed by working in mortar

from above. Stretcher brick in the facing

wythe were laid to the elevation of the header

course before the bacldng wythes were laid. In spreading the bed joints for the backing,

the mortar was curled against the facing wythe

to form a cove, filling the lower portion of the

collar joint. The filling of the collar joint was

then completed by worldng in mortar from

above.

For the walls of hollow masonry units faced

with brick, the joints in the brickwork were

filled with mortar as described. The facing

brick were laid to the elevation of a header

course and the back of the facing wythe was

then parged with at least % inch of mortar

before the hollow imits of the backing were set. Joints in the backing were completely filled. The face joints on the exposed face of the wall were tooled to form a concave surface. A round

metal bar of diameter slightly larger than the

thickness of the joint was used to pack the

mortar in the face joints forming a smooth hard

surface.

(6) Class B

Figure 6 illustrates class B workmanship.

As small an amount of mortar as was practicable was used. The mason was instructed to use a

"light" trowel and to follow the technique

usually employed in contract construction.

The mortar beds were furrowed. The cross

joints were made by buttermg lightly the outer ends of the stretcher and outer edges of the

header brick that lay in either face of the walls. The collar joints, between the wytries, and the

interior of the cross joints were not filled. Only

the face shells of hollow vmits were provided

with mortar beds, and cross joints were made by

buttering the edges of the unit that were ex- posed in the face of the waU. There was no

[10]
Figure 6.—Wall 32-'iO (ht>lJBj), ilUtilraling

workmanship B.

a, front view, and 6, back view, showing open cross and collar joints.

parging on the back of the facmg wythe and the

interiors of all vertical joints were left unfilled. The mortar joints in both faces of the wall were

' "cut" by drawing the edge of the trowel along

j the joint, cutting off excess or protruding mor-

! tar. The surface of the cut joints was rough in

j texture.

(c) aass C

This workmanship was the same as class A

except that the mortar joints were cut without

I subsequent tooling.

(d) aassD

This workmanship was the same as class B

except that the joints in the exposed face were

tooled to form a concave surface in tlio same manner as for class A workmanship.

(e) Class E

This is according to the specification for the

Techwood Slum Clearance Project, Atlanta,

Ga. This class of workmanship was used for the construction of two of the walls built with

a facing of brick b and a backmg of Techwood

tile. This workmanship is the same as class A

except that no mortar was placed in the central

3-inch thickness of the tile backing except that

for bedding the header bricks. The tile were

set on end and only the two longitudinal face

shells were provided with bed and cross joints.

5. Aging

After completion, the walls were allowed to stand in the laboratory for 2 or 3 days without

being moved. The walls were then whitewashed on the ends and back and placed in the

drying rooms. After 1 month or more, depending upon the time required for drying, the walls were given the fu-st permeability test. They

were also dried thoroughly between successive

tests. The drying rooms were ventilated and

heated to at least 30° or 40° F above mean

outdoor temperature. The air inside the room

was circulated around the walls by means of

fans. The dryness of the walls was determined

by weighing them on a platform scale. When

a wall had lost less than about 0.2 percent of its weight in 7 days' time, it was considered dry

enough for test.

IV. METHOD OF TESTING

PERMEABILITY OF WALLS

A fixed testing procedure was followed and

the tests on each waU were made in the same

order. The tests were designated as the capillarity, heavy-raia, and Hght-rain tests. Only

a limited number of walls were given the lightrain tests. Nearly all of the comparative data

used in this report were obtained from the

heavy-rain test, maldng it the most important

as well as the most severe test given to the

walls. The duration of the tests was for 1 day, or until failure, with the exception of a few tests made on walls that showed neither

leakage nor dampness during exposures of 1 or 2 weeks.

[11]
1. Capillarity Test

In the capillarity test the water penetrated

the walls under the forces of capillarity and

gravity only. The wall was supported in a vertical position on the floor of the testing room

and the water was applied near the top of the

exposed face by means of a perforated metal

pipe. The streams from the perforations were

about 1 inch apart along the axis of the pipe

and they merged into a thin sheet of water

running down the face of the wall. The

amount of water applied was about 10 gallons

(38 liters) per hour per lineal foot of wall. Metal strips were supported at the ends and

across the top of the wall so that the streams of

water did not impinge against the masonry

near the parging.

2. Heavy-Rain Test

This test was made after the capillarity test had been completed. The conditions of ex- posure simulated the effect of a windstorm

accompanied by a heavy rain. The exposed

face of the wall was subjected to an air pressure

of 10 pounds per square foot above the atmospheric pressure on the back of the wall, so that a pressure gradient existed within the wall. The wall was supported on metal skids and

clamped into position so as to form one side of an airtight pressure chamber, as illustrated in

figure 7. Water was applied to the top of the

Figure 7.

Isometric projection of testing rliamher.

wall through a perforated metal tube, so that

the face of the wall was covered with a sheet of

water, as in the capillarity test.* The joint

between the wall and the chamber was made

airtight by means of a sponge-rubber gasket.

Since the opening in the chamber was 3 feet wide, no water was applied directly to the parging at the sides of the wall. The top of the

wall was flashed with a combination of spongerubber and copper gaskets. The pressure ^ chamber was equipped with observation win- ' dows, a manometer, a gooseneck water outlet,

| and a sensitive pressure-relief outlet. ^

3. Light-Rain Test ^ Light-rain tests were made only on some of

the walls that had been found most permeable ! in the heavy-rain tests. The test differed from

the heavy-rain test only in the amount of

' water applied and in the method of application. The wall was exposed to an air pressure • of 10 pounds per square foot in the testing ^ chamber (fig. 7) and water was applied to the

'

face in small measured quantities by means of

atomizers. Two atomizers, mounted one over

| the other on a carriage, moved horizontally ; back and forth in front of the wall. The sprays, i elliptical in shape with the long axes vertical, 1' were so adjusted that each covered one-half of the wall elevation with a slight overlap at mid- | height. The amount of water applied per hour was about 0.5 gallon (about 2 Hters) per lineal \ foot of wall, equivalent to a depth of approxi- j mately 0.2 inch per hour over the exposed surface. \ V. RATING OF PERFORMANCE I

1. Observations i Three general types of observation or meas- * urements were made to determine the perform- ance of a wall. These were: (a) time for the

penetration of moisture through the wall or the

facing, (b) measurements of the maximum rate

of leakage through the wall, and (c) the appearance of the wall during and after a test.

(a) Time Required for Penetration » Time measurements included the first appearance of a damp spot in the back of the

^ *When the leakage through the wall or facing was large, it was some- 1 times necessary to apply more than 10 gallons of water per lineal foot of

j wall.

[12]
wall, a leak through the wall, and the indication

in the lower flashing of facing leakage that had

penetrated downwards through the wall to the

flashing. These observations are given for each

wall in table 4. The designation "leak, through

facing", of course, indicates the time for observation of a type of failure (leak from the

lower flashing), rather than the actual time at which water first penetrated the facing wythe.

The time values given in table 4 are usually

correct within limits of plus or minus 10 perj cent. Although the times for the appearance

I and the location of subsequent damp spots and

leaks were recorded, they are not included in

this report.

(b) Rate of Leakage

The rate of leakage through the wall or the

facing was determined by measuring the water

caught in an interval of time on the upper or the

j lower flashing. The measurements were made

at frequent intervals throughout a test or until

a maximum rate of leakage was observed.

(c) Appearance of Wall During and After Test

The appearance of the walls under test was

closely observed and recorded at the end of 1 day and at the end of the test. The location and

extent of damp areas was drawn on mimeographed sketches representing the back of each

wall. The intensity of saturation of damp

areas was roughly determined by touching with

the fingers, and the presence or absence of

visible drops of water on the back of the wall was noted. The only data on the appearance of

the wall that was used in establishing a criteria

for performance was the percentage of damp

area on the back of the wall. The degree of

saturation of the damp areas was difficult to express in definite terms.

2. Arbitrary Ratings

A system of rating was established in order

to classify the walls according to their comparative resistance to penetration by water. The

method of rating was arbitrary because the

exposures in tests continued for several hours

were more severe than natural exposures for most building walls. The backs of the walls were not plastered and the high relative humidity in the testing room prevented the drying

which would occur on the interior surface of

walls in heated buildings. It is not known

whether or not the permeation of moisture

through the test walls, as evidenced by damp

areas, would have produced visible dampness on

plaster applied directly to the wall. When the

amount of moisture penetration was sufficient to cause dampness on more than 50 percent of

the wall area in 24 hours or less, it seems likely

that the plaster would be damaged even though

no visible dampness would appear. It is probable that damp areas on the plaster would

have resulted in those cases where leaks penetrated the walls or where water could be

plainly seen in the joints.

Measurements of the leakage through the

walls indicated that the rate of leakage gradually increased to a maximum as the wall materials approached saturation, and then decreased

very slowly with continued exposure. There was no correlation between the location of the

leaks in the brick masonry walls and the kind

of brick or workmanship. It appeared to be

largely a matter of chance whether the leakage

appeared on the back of the wall or on the lower

flashing. However, it is probable that with

increase in wall height, a relatively greater

amount of the water that penetrated the facing

would pass through the wall, especially if aided

by a pressure gradient. For this reason the wall

ratings were so classified as to give low ratings

to all walls that leaked. The ratings of the walls

are listed in table 4 and are as follows: Excellent

(E), walls having no leaks through either the

wall or the facing wythe, and less than 25 per- cent of the wall area damp in 7 days; good (G),

walls having no leaks through either the wall or the facing wythe, and less than 50 percent of

the wall area damp in 1 day; fair (F), walls

having 50 percent or more of the wall area damp

in 1 day, and/ or having a leakage through the

wall or facing of less than 1 liter per hour ; poor

(P), walls having a leakage of less than 1 liter of water per hour through the M-all and less than 15 liters of water per hour through the

facing during the first day; and very poor (VP),

walls having a leakage of more than 1 liter of water per hour through the wall or more

than 15 liters of water per hour through the

facing.

[13]
VI. PERFORMANCE OF WALLS

L Consistency of Results

The results of the wall tests have hi general

been consistent enough to indicate at least the

relative advantages or disadvantages of differ- ent workmanships, kind or combmation of

brick, kind of mortar, and wall thiclvuess. The lack of flashings in some of the earlier walls built with structural clay tile backmg

made it difficult to determine the exact reason

for leakage at the bottom of these walls. Nearly all of the walls on which it was neces- sary to make repeated tests of the same kind

showed a decrease in permeability in successive

tests.

2. Effect of Variation in Methods of

Testing

(a) Comparison of Capillarity and Heavy-Rain

Tests The only difference between the capillarity

and the heavy-rain tests was in the air pressure

applied. No pressure was used in the capillarity test, but 10 pounds per square foot was

applied in the heavy-rain test. Some idea of the relative severity of these tests may be

obtained from the data presented in table 5. Table .5.

Relative performance of all-brick walls under

capillarity and heavy-rain tests [PerformancB under capillarity test taken as unity. Average of two to four walls, unless otherwise noted]

Thickness (in.) Workmanship

Relative time for penetration as indicated by- Relative

area damp

after

1 day

Relative amount

of Dampness Leakage

leakage

Brick a

8 A 0. 07 1. 4

12 A >. 25 1.0

8 B .29 0. 45 1.

1

3.

1

12 B . U . 13 1.

1

2.7

Brick b

8 A 0. 05 0.01 1.0 3. 1 12 A .04 1.6

8

12 B

B

.45 .06

.21 .021.0

1.3 3.6 5.9

Brick c

8 A 0. .54 0.08 1.

1

4.0

12 A . 18 1.6

f> B .30 .03 1.0 2. 9 12 B .29 .05 1.

1

4. 1

« 1 wall only.

Most of the walls which leaked in the heavyrain tests had leaked in the capillarity tests. The effect of the air pressure was to reduce

greatly the time required for moisture penetration and to increase greatly the amount of

leakage through the walls. The reduction in

time required for moisture penetration in the

heavy-rain test, as compared to that observed

for the capillarity test, appeared to be slightly

greater for walls of workmanship A than for those of workmanship B. The thickness of the

walls did not greatly affect the relative times

required for penetration, but it was found that

pressure increased the permeabilities of walls

of brick h relatively more than those of either

brick a or c.

(6) Comparison o f Light- and Heavy-Rain Tests

Since light-rain tests were made only on a small number of the more permeable walls, a proper comparison cannot be made on the

relative severity of the light- and heavy-rain

tests. By averaging the available data, it was

found to take about 50 times as long for dampness to penetrate the wall during a light-rain

test, and about 200 times as long for the appear- ance of leaks through the facing as was required

for the heavy-rain tests.

VII. EFFECT OF KINDS OF WORKMANSHIP OR MATERIALS USED IN WALLS

OF BRICK MASONRY

1. Comparison of Workmanship

The results of the tests have shown that

workmanship was the most important factor

affecting the permeability of brick walls of

common American bond. A comparison of the

performances of walls of workmanships A, B,

C, and D is provided by the data in table 6

for individual walls of brick a and of brick c. This table gives the detailed results of the

heavy-rain test on each wall. The data show

that the resistances of walls with workmanship

A were markedly greater than for the others.

In order to illustrate more clearly the data in table 6 the salient features of each kind of

[14]
Table 6.

Effect of workmanship on performance of brick walls based on results of heavy-rain tests

Wall Designation Duration

of test

Time to fail, as indicated by

Area damp

at end of

test

Maximum leakage per hour

Kating

Damp

through

wall

Leak

through

wall

Leak

through

facing Through

wall Through

facing

Walls of Brick a and Mortar 2,, 12-ineh Thick

3-65 8-64

11-68

12-69

aal2A2 _ Days8

17

1

hr hr hr %

035

30

25

Liters

0

0

0

0

/ iters0

110

3

E

P

ap

aal2B2 2. 2 42 ±3

4

0. 03 aal2C2 aal2D2 .45

Walls of Brick c and Mortar 2, 12-inch Thick

49-35 CC12A2 1 7 ±1 ---- 30 0 0 G

57-37 CC12B2 . 1 0. 20 0. 55 ±0. 2 0. 13 95 1 ICO VP

63-7! CC12C2 1 .37 .53 50 0 0.5 F

64-70 C012D2 1 .25 15 ±6 .13 75 .5 C7 VP

workmanship are given below in the order of

their least permeabihty.

AVork- manship

Face joint treatment Kind of joint inside of wall

Order of least per- meability

A Tooled Solid 1 C Cut ___do 2 D Tooled Open 3 B Cut _^.do 4

It can be seen for walls of similar interior

construction that tooled joints were more

effective than cut joints. The effect of jomt

treatment was not, however, of sufficient magnitude to overcome the influence of the type of workmansliip used inside the wall.

2. Effect of Wall Thickness and

Kind of Brick

Data on the effects of wall thickness and kind

of brick were obtained from tests on a group of 48 walls representing the four variables: workmanship, thiclmess, brick, and mortar. The

specific variables in this group were workmanship A and B, wall tliiclmesses 8 and 12 inches,

bricks a, h, and c, and mortars 1, 2, 3, and 4. Each workmansliip and waU thickness was

represented by 24 walls, each brick by 16 walls,

and each mortar by 12 walls. As it was

found that the effects of difference in the

mortar were similar for each brick, the test

data were averaged for groups of four walls of

like brick, thickness, and workmansliip. These

averaged data are presented in table 7. Data

which departed markedly from the average were not included in the values given in table

7; less than 10 determinations out of a total of over 900 were rejected.

Because of the relatively high permeabifity of walls of workmansliip B, the effect of increasing

the wall tliickness from 8 to 12 inches was more

noticeable for walls of class A than for those of

class B workmanship. The length of time re- quired in heavy-rain tests for the penetration of dampness through 12-inch walls (average of aU

brick) was usually more than 50 times as great

as for the 8-iiich walls of workmanship A and was about 6 times as great with workmanship B.

This dift'erence is probably because the penetration in class A construction walls was by

capillarity, whereas it took place thi'ough interstices in the masonry of class B construction

walls. It is evident from the data of table 7 that for workmanship A the least permeable walls were

those built of the least absorptive brick, whereas

the data for the walls of workmanship B do not

show a consistent relation between the per- formance of the walls and the absorptive properties of the bricks. As pointed out later, the

performance of the walls of absorptive brick

might have been better if these bricks had

been wetted thorouglily before use in construction.

90G94°—38 3 [15]
Table 7.

Effect of wall thickness and kind of brick on performance of "typical" -walls

[Each value is the median for four or more walls which were alike except for the mortar]

Designation

aal2A.

.

bbl2A.

CCl2A._

aaSA-—

bb8A_.

cc8A_._

aal2B__

bbl2B_

ccl2B__

aa8B___

bb8B_.

cc8B___

Test Duration

of test

Time to fail, as indicated by

Damp

through

wall

Leak

through

wall

Leak

through

facing

Lfdys hr hr hr C 8 HR 7 29 HR 3 24 LR 1 19

.i 22 HR " LR 1 12 r 72 HR 48 c

, 0 50 HR J ^03 0. 05 1.3 LR 1 2. 8 Q 0. 75 HR n. 8 .42 4 LR 5

1. 9 0. 10 HR 0. 83 . 08 LR 1 12 5 c 1 8 0. 58 HR n. 8 0. 07 0 03 03 LR 6 15 15 1.2 12 1. 1 HR 0. 8 0.25 5 10 LR 10 C 0. 17 0.25 0. 03 HR 0.8 . 05 . 12 .05 LR 9 12 .43 C 0. 05 0. 27 . 13 HR 0.8 .02 .03 .05 LR 3 15 4 C 0.9 0. 17 2 0. 50 HR .2 .08 0. 10 . 58 LR 1 6 15

Area damp

in 1 day

100

100

75

9068

3545

57090

55

75

85

20

70

70

3

100

87 100

100

100

Maximum leakage per hour

Through

wall

Liters0

00

0

0

0

0

00

0

04

0.3

0

0. 5 0

04

0

. 5 .5.02

.5

2

0

13

0.

1

428

0. 2

331

1. 6

Through

facing

Liters0

000

0

0

0

0

00

.5

. 5 0

0

0

513

0. 1 10

60

1. 4 2460

0. 5

5180.4

1425

0.3

17

500.1

3. Effect of Absorptive Backing

The effect of combining a low-absorptive

brick facing with a Mgh-absorptive brick backing was determined from tests on two walls;

81-86, designation ac8A2; and 82-87, designation ac8B2. The performance of these walls in

heavy- and light-rain tests is compared in table 8

with the performance of similar walls built entirely of brick a or of brick c. From the data on the heavy-rain tests given

in table 8, wall 81-86, of class A workmanship,

gave the best performance and proved superior

to wall 14-60 built entirely of low-absorptive

brick. All of the walls of class B workmanship leaked badly. In the light-rain tests on

walls of class B workmanshiiD, wall 82-87 gave

a slightly better performance than the other

two. This wall was the only 8-inch wall of

class B workmanship to be given a rating of good in the light-rain test. The results of these tests indicate that when

the amount of water penetrating the facing

wythe was small, the relatively large absorptive

capacity of the brick c bacldng was of some

advantage in delaying penetration of dampness

and in retarding leaks through either the wall

or the facing. The impervious brick facings

in walls 81-86 and 82-87 had, respectively,

similar effects in the heavy- and light-rain

tests inasmuch as they greatly reduced the

amount of water passing into the backing.

The walls of workmansliip B built entirely

of brick c were slightly more resistive than

those built of brick a. Apparently the absorption of water by brick c delayed the penetration of leaks until the wall was nearly saturated.

[16]
Table 8.

Effect of combining a high-absorptive brick backing with a low-absorptive brick facing

Wnll Designation Duration

of test

Time to fail, as indicated byArea damp

at end of

test

Maximum leakage per hour

Rating

Damp

through

wall

Leak

through

wall

Lenk

through

facing Through

wall Through

facing

Heavy-Rain Tests

14-60 81-86 66-36

19-61 82-87

70-34

aa8A2 - Days30

1

1

]

. 2

hr 57 ±1

84 ±5

0. 25

.05

.05

.03

hr hr %

70

100

100

8

100 100

Liters

0

0

5' 51

Liters0

0

. !j

20

200.5

a

GFVP

VP

VP

ac8A2

CC8A2 aa8B2

ac8B2

ce8B2

0.45

.32

.03 .05

0. 45

.03 .33

1.8 ±.5

Light-Rain Tests

20-57 82-87 69-30

aa8B3

ae8B2

1

11

9 ±2

3.5

5. 5

18 ±4 9 ±2 83

4530

0.2

00

0.4

0

.0

F

G

ceSBl 15 ±5 F

4. Comparison of Mortars

(a) Effect of Varying Percentages of Lime and

Cement in Alortars of High Water Retentivity

The permeabilities of brick walls constructed

with mortars 1, 2, 3, and 4 are given in table 9.

The values in the table were computed in a manner similar to those given in table 7, using

the data from tests on the same 48 walls. Each value is the average for the results of

tests on the three walls which were similar

except as to kind of brick.

Table 9.

Effect of composition of mortar on performance of "typical" brick walls

[Each value is the median for three or more walls which were alike except for the brick]

Designation

-12A1

-12A2

-12A3

-12A4

-8A1.

-8A2.

-8A3.

-8A4_

-12B1

-12B2

-12B3

-12B4

-8B1.

-8B2.

-8B3.

-8B4.

Test

C

HR

C

HR

C

HR

C

HR

C

HR

C

HR

C

HR

C

HR

C

HR

C

HR

CHR

C

HR

C

HR

C

HR

C

HR

CHR

Duration

of test

Days

6

56

6

6

4

Time to fail, as indicated byDanip

through

wall

hr

139

120

125

115

12536

127 117

6546

22

19

10.

1.:

7. 5 0.38

.83

2

0. 52

3

0. 18

. 10 .05

. 17 .03

.17 .07

Leak

through

wall

hr

12

5

13

8

9

0. 80

.07 .42

. 13

10.13

.69

.03

Leak

through

facing

0. 10

. 10 .42 .07

2

0. 12 .20

. 12

. 10 .08

11

0. 15

. 12 .12

.07

Area damp

in 1 day

Maximum leakage per hour

Through

wall

Liters

0

0

00

0

00

0

0. 5

Through

facing

Liters

0

0

0

0

00

00

0

00

0

0

0

1569

14

50

3IS

9

41

25

68

416

1247

[17]
Table 9 shows an anomaly for the 12-inch

walls of workmanship A. Although days are shown to be required for the penetration of moisture to the back of the wall, a definite damp

area in 1 day is also given. The inconsistency

is due to the fact that most of the walls of brick a were not penetrated by dampness, but the

walls of bricks b and c were usually partly damp

after exposure for 1 day.

The data in table 9 indicate that mortar 1 (high -cement-low-lime) was the least permeable. The addition of a metallic stearate to one of the mortars (No. 4) had little effect on

the permeability. Variations m the proportion

of cement to lime in the mortars did not affect the permeability of the brick walls as much as changes m the workmanship, the thiclaiess of

the wall, or the kind of brick. However, for walls of workmanship A the performances of those with mortar 1 were distinctly better than

for those with the other mortars, and the per- meabilities were slightly less with mortar 2 than with mortars 3 and 4. With workmanship

B, the performance was about the same for mortars 1 to 4, inclusive.

Although the composition of the mortar had

a measureable effect on the permeability of the

walls, the data of tables 4 and 7 for walls of brick a and workmanship A show that the

penetration of water through the mortar was

very slow. Usually more than 1 day was re- quired for dampness to penetrate the 8-inch

walls and more than 1 week the 12-inch walls. These results indicate that the amount of water

passmg through the solid mortar joitits was

small in comparison to that flowuig through

openings in the walls which leaked early in the

tests.

(6) Effect cf Using a Mortar of Low Water

Retentivity

Although mortars 1 to 4 were of a workability

satisfactory to the masons, the bricklayers complained vociferously whenever using mortar 5, which was a cement-hne mortar (1:1:6 by

volume) and was the same as mortar 2 except

for the quality of the lime. Five brick walls were constructed with this mortar. The numbers, designations, and performances of these

walls are included in table 10, which gives data

for comparing the performance of these walls

with similar ones built with mortar 2. The construction of wall 17-92, designation

aa8A5, was marked by floating (settling and

slipping) of the brick and excessive bleeding

(separation of the water) of the joints. Although the low-absorptive brick a usually had some tendency to float with the other mortars, more of this difficulty was experienced in the

construction of this wall. The construction of walls of brick c with mortar 5 was difficult * because of the strong brick suction that imme- | diately stiffened the mortar. The oven-dried

brick, particularly, were hard to level after the ; completion of a course, and many brick were ' broken by the mason when attempting to hammer them into position.

All of the walls containing mortar 2 were less permeable than similar ones containing mortar

5. The superiority was most marked for workmanship A. For workmanship B the walls

built with mortar 5 had nearly double the

leakage of those built with mortar 2. The

data are consistent in showing that the per- formance of walls with mortar 2 was better than

those with mortar 5, whether judged by time

for dampness to penetrate, time for leakage

(if any) to start, or rate of leakage.

As pointed out previously, there was not a

large difference in the performances of walls

with mortars 1, 2, and 3, the permeabilities

increasing only slightly with an increase in the

ratios of lime to cement in the mortars. The

water retentivites of these mortars were high;

the values for flow after suction ranged from 87

to 109 percent (mitial flow 130 percent). All were "fat" and all were so nearly alike in their

working properties that the masons were unable

to distinguish one from another with certainty.

Both the performance of walls in the permeability tests and the testimony of the masons indicate, therefore, that the qualities of cement-lime

mortars which are related either to permeability

of walls or workability were not controlled by

ratio of cement to lime in the mortars. Moreover, the performance of mortar 5 indicates

that a mortar showing a low value for flow

after suction is not satisfactory to the masons

nor is it suitable for use in exterior walls of buildings where freedom from rain penetration

is of importance.

[18]
5. Effect of Brick Suction

The maximum permissible absorption of

brick when laid was limited in most of tlie walls

(section III (3)) to 50 grams of water ab- sorbed in 1 minute (brick laid flatwise in ji in. of water). To meet this requirement it was

necessary to wet the liigh-absorptive brick c before laying. In order to determine the effects of a high brick suction, four walls were constructed using brick c that had been oven-dried

to constant weight. The results of tests on

these walls are given in table 10. The effects of using dry or damp brick can be obtained by

comparing the performance of walls 62-A20

with 61-A18, 58-67 with 57-37, 55-A19 with

54-A17, and 50-66 with 49-35. The effect of

brick suction is most marked for walls of class ^

workmansliip and mortar 2, and is least noticeable for class B workmanship and mortar 5. This is to be expected as nearly all walls of class B workmanship were very permeable. As all available data indicate that the permeability of

walls increase with increases in the absorption

of the brick at time of laying, it is probable that

the performance of the walls built Avith damp

brick would have been better if the brick had

contained more water. ^ Even so, none of the

walls of brick a or the dampened brick c with

workmansliip A leaked, whereas both of those

of the liigh-absorptive brick c (set dry) leaked.

Although the data are meager, they indicate

that the wetter the bricks (less the absorption or brick suction) the less permeable the masonry.

Table 10.

Effects of ivater retentivily of mortar, plasticity of lime, and suction of brick on performance of brick walls

[Heavy-rain tests]

Wall Designation Duration

of test

Time to fail, as indicated by

Area damp

at end of

test

Maximum leakage per hour

Rating

Damp

through

wall

Leak

through

wall

Leak

through

facing

Through

wall Throughfacing

Brick Taken From Dry Storage

14-60 aa8A2 Days

3

1

hr 57 ±1

12. 5 d=2. 5

hr hr or

/O 70

50

Liters

0

0

Liters

0

0 G

17-92 aa8A5 F

Brick Damp When Laid

4&-35 ccl2A2-_ 1

1 7±1

0.23

30

78

0

0

0

0 G54-A17 CC12A5..-. F

Brick Oven-Dry When Laid

50-66 55-A19 CC12A2

CC12A5 - .__ 0.65

1

0. 43 .421.3

0. 75 2.33 10093

0. 5.2 0.5

.3 F

F

Brick Damp When Laid

57-37 61-A18 CC12B2

CC12B5

1

1 0.02.08

0. 82

. 12

0. 13 .0895

95 5 100 244 VP

VP

Brick Oven-Dry When Laid

58-67 CC12B2 . 1 0.25 0.68 0. 07 90 3 127 VP

62-A20 CC12B5 1 .05 . 10 . 10 100 249 VP

None of the data pertaining to the effects of

kind of brick, absorption of brick when laid, or kind of mortar support an often expressed

view that mortars should be adapted to the

bricks. The best performance was shown by

walls with mortars of high flow after suction,

irrespective of the kind of brick used ; and

imiformly better results were obtained with

brick of low absorption than with dry highabsorptive brick.

1 Permeability tests of S-in. brick waUettes, Proc. Am. Soc. Testing Materials 34, pt. II, 419 (1934).

[19]
6. Effect of Using Blind Headers

The effect of using two-tliird "blind" headers

in 8-inch walls of common American bond is shown by the data in table 1 1 . The walls containing blind headers were constructed in the

usual manner except that two half brick were

placed in the facing wythe between full headers

in each of the header courses, leaving one-third

of the headers full. The blind headers were

placed with their ends outward and they were backed by stretcher brick in the second wythe.

Table 11.

Effect of using two-thirds "blind" headers on performance of brick walls of common American bond

[Heavy-rain tests]

Wall Designation ' Duration

of test

Time to fail, as indicated by

Area damp

at end of

test

Maximum leakage per hour

Rating

Damp

through

wall

'Leak through

wall

Leak

through

facing

Through

wall Throughfacing

Days hr hr hr % Liters Liters 14-60 aa8A2-f 3 57 ±1 70 0 0 G

73-89_. aa8A2-b 2 44 ±3 75 0 0 G

36-53 bb8A2-f 1 0.02 0.08 100 0 F

74-90 bb8A2-b 1 .03 90 o"' 0 F

66-36 cc8A2-f 1 .25 .45 0.45 100 . 5 .5 F

75-38 cc8A2-b 1 .26 .38 1 ±.5 100 3 .5 VP

19-61 aa8B2-f 1 .05 .32 0.03 80 0. 5 20 VP

76-88 aa8B2-b 0.1 .02 .02 .03

.07

50 5 6 VP

Avg2 bb8B2-f .6 .03 .03 100 30 23 VP

77-91 bb8B2-b 1 .03 .03 .03 100 6 67 VP

70-34 cc8B2-f 0.1 .03 .05 1. 7 ±1 100 61 0.5 VP

78-39 cc8B2-b .2 .10 .18 0.18 100 1 66 VP

1 Letter f at end of designation indicates full headers; letter b indicates two-thirds "blind" headers.

2 Average for walls 40-22 and 49-A9. The use of blind headers had no significant

effect on the performance of the walls of workmanship A. For those of worlonanship B with

bricks b and c, the use of blind headers caused

the measured leakage through the facing to be

greater and that through the wall to be less than for the waUs with full headers. Although

there may have been a tendency for water

passing thi-ough the facing to drop down between the wythes in walls of workmansliip B

with blind headers, the data of table 7 show that

most of the walls of workmanship B had much

greater leakage from the facings than through

the walls. It must be concluded, therefore,

that the data obtamed show neither a marked

nor consistent effect resulting from using half

brick for two-thirds of the units in the header

courses.

7. Effect of Mortar Parging on Brick

Facing

Four 4-inch brick walls were constructed with

workmanship A with a }^inch mortar parging on the back. To increase the stability of the

walls, a 4- by 4-inch brick pilaster, 15 inches

high, was built into the brick at each end of the

wall. The pilasters contained a full header

brick every other course and were covered with

parging. The walls were flashed between the

pilasters with a strip of copper inserted in the

bed joint above the first course before the mortar had set and before the wall was parged.

Mortar Iw used in two of the walls was the same

as mortar 1, except that it contained 0.2 percent

of ammonium stearate, by weight, of cement

plus lime.

The data on performance of these walls are given in table 4 (wall 83-A13, 84-A15, 85-A14,

86-A16). The penetration of moisture through

these walls was usually first indicated by a damp spot near the upper and inner corner of

each pUaster. Although water penetrated under the wall and stood in a pool on the supporting channel, leakage from the flashings was less than 1 liter per hour. As the water leaking

through the facing appeared to run down the back

of the wall between the brick and the parging, it was difficult to determinehowmuch,if any, water

had penetrated the parging. Considering their

thickness, the performance of these walls was

exceptionally good, and about equal to the per- formance of the 8-inch walls of similar brick

[20]
and workmanship. The absence of headers in

these walls (except at the pilasters) might have

been responsible for their good performance.

The rating E of wall 84-A15 in the capillarity

test indicates that the waterproofing in mortar

Iw might have been more effective in the highcement low-lime mortar than in mortar 4, which contained more lime.

8. Effect op a Stone Belt Course

Two 12-inch brick walls of workmanship A

were built with a limestone belt course embedded in the two facing wythes. The courses were of Indiana limestone that had been stored

outdoors for several years. The stones were

thoroughly cleaned and scrubbed with sand and

water before using in order to remove stains

and organic materials from the surfaces. The

courses (30 in. long, 9 in. deep, and 7 in. thick

at the face edge, increasing to 7.5 in. at the back) were set on the fifth stretcher course with the

faces projecting 1 inch from the face of the wall

and were provided with a drip under the face

edge. Three courses of half stretchers were

placed at each end of the belt course with full mortar joints around the ends and back of the

stone. The stretchers in the backing wythe

were brought up to level with the top of the stone and covered with a rear header course over the collar joint between the stone and the

backing wythe. The walls were of common

American bond above the belt course. Table 12.

Effect of a stone belt course in a brick masonry wall

[Heavy-rain tests]

Wall Designation ' Duration

of test

Time to fail, as indicated by

Area damp

at end

of test

Maximum leakage per hour

Rating

Damp

through

wall

Leak

through

wall

Leak

through

facing

Through

wall Throughfacing

3-65 79-84 Avg ! 8-85aal2A.2

Do.ys

8

32.7

1

hr hr lir o-/ /o 0

540

10

Liters

0

0

0

0

IJters 0

00

0

E

E—G

G

G

aal2A2-S 2629

9 bbl2A2.-. bbl2A2-S

' S at end cf designation indicates stone sill.

In table 12 the performance of walls with a

stone belt course in the heavy-rain test is compared with that of the other brick walls. The

walls containing stone belt courses were slightly more permeable than similar walls without belt

courses. The first damp spots were usually

noted opposite the lower corners of the stones. There was no leakage (measurable flow) from

any of these walls. The use of a belt course with brick backing

did not increase greatly the permeability of

brick masonry walls of class A workmanship.

VIII. EFFECT OF WORKMANSHIP AND

MATERIALS IN WALLS CONTAINING

HOLLOW MASONRY BUILDING UNITS

1. Walls With Structural Clay Tile

Backing

The data on the performance of walls with a

fncing of brick and a backing of structural clay

2 Average of tests on walls 25-37, 25-A4, 27-A6.

tile are given in table 4. Most of these walls were not provided with flasliings, and, for this reason, rates of leakage were not measured.

During the tests of walls without flasliings,

water sometimes flowed under the walls between

the masonry and the supporting channel. The

uncertainties resulting from the lack of flasliing

made difficult the determination of the time

elapsing before failure. This difficulty was in- creased somewhat by the manner of failure of

these walls. The amount of water passing

through the brick facing seemed to be about the same as for the other walls of the same brick and

workmansliip, but a larger proportion of tins water dropped down through the tile backing

than through the backing in the 12-inch brick

walls. The performance of the walls with tile backing was aft'ected more by the quality of the workmanship than by any other factor. The walls

of workmansliip B leaked considerably at the

[21]
bottom and the cells in the lower courses were

partially filled with water. However, on the

average the performance of these walls was a

little better than for typical 12-inch walls of

brick b and workmanship B. The performances in the capillarity test of the tile walls of

workmanships A and E were somewhat superior on the average to those of the 1 2-uich walls

of brick b and workmansliip A. In the heavyrain test they were inferior. On accoimt of the

small number of specimens and their apparently

erratic behavior, the data do not provide a positive indication as to the relative merits of end

and side construction tiles.

2. Walls With Backing of Hollow Concrete

Units

All of the walls with backing of hollow concrete units were furnished with lower flashings

extending under the wall to the first bed joint

in the facing wythe. Data on the performance

of these walls during the heavy rain tests are given in table 13. It appears that consistent

results were not obtained from walls built of

the same workmanship and materials, possibly

because of differences in the permeability of the

facing wythes. For class A workmansliip the

walls with cinder-concrete backing were slightly

less permeable than those with stone-concrete backing. The kind of concrete had little effect on the permeability of walls of class B workmanship.

Table 13.

Performance of walls with backing of hollow

concrete units

[Heavy-rain tests]

Wall Designation

Dura- tion

of

test

Time to fail, as indicated by

Area damp

at end of test

Maxi- mum

leak- age per hour

Rating Damp

through

wall

Leak

through

facing

105-80 bml2A2.._-

bml2A2.... bml2A?

Days

11

1

hr

0. 17

2. 3 1.3

hr0.73

5.5 20 ±3

/o 10030

35

Liters

6

0. 5

. 01

P

F

F

106-A3 107-A5 Avg

108-78

bnil2A2^___ bnl2A2

1 1.3 8.7 55 . 5 F

130. 13 50 ±10. 58 63 ±560

17

. 5.05 F

109-93 bnl2A2 G Avg

112-81

bnl2A2 bml2B2

bnl2B2

2 25 32 34 .5 F

1

1 0.07.08 0.03.03 90CO

93

159 VP

113-79 VP

The permeability of walls with backing of hollow units was dependent mostly upon the

effectiveness of the brick facing. Since the

performances of walls of brick b and workmanship A were found to be more erratic than those

of walls built of bricks a or c, it follows that the

permeability of the walls with hollow unit

backings and brick 6 facings may have been

influenced by irregularities in the performances

of the facings. In general, it was found that the more absorbent the hollow-unit backing, the

larger the damp area on the back of the wall. This would seemingly indicate a difference in

the type of fadure dependent upon the absorption of the backing. Because of the possible

erratic behavior of the facings of brick b, the

absence of flashings on many of the walls which

made comparison difficult and the probable

difference in the manner of failure of walls with

imits of high or low absorption, the relatively

small dift'erences in the performances of walls

with backings of hollow units may not be

significant.

Walls 110-A12 and Ill-All were, respectively, of stone- and cinder-concrete units without

brick facings. These walls offered little resist- ance to penetration of water (see table 4).

3. Stucco Facing on Structural Clay Tile

The walls constructed with two }^-inch facing- coats of stucco on a backing of 6-cell 8- by 12- by 12-inch clay tile were the least permeable of

all walls containing hollow masonry units.

These walls were built with the tile either on

end or on side and with plain or waterproofed

stucco, either with smooth or rough textural

finish. The numbers and structural details of

these walls are listed below.

Wall Kind of tile construction Kind of stucco ' Texture of stucco finish coat

97- 1 98-2 99-3 100-4 101-5 102-6 103-7 104-8

End Plain Smooth.

Rough.

Smooth.

Rough.

Smooth.

Rough.

Smooth.

Rough.

do

do

do

do

Waterproofed__

do

Side Plain do

do

do

do

Waterproofed _ do

The plain stucco was mixed in the proportion by weight of 1 part of Portland cement to 3 parts of dry sand. The waterproofed stucco con- tained 0.2 percent of ammonium stearate, by weight of cement.

[22]
The data on performance of the stucco walls

in the heavy-rain tests are given in table 14. At the end of these tests all of the walls were more or less damp at the sides, top, or bottom

because of the penetration of moisture through

the parging, or imder the wall. Dampness

from this cause was not considered in determining the time to failure, but it was included in

calculating the damp area on the back of the

wall. Some of the walls were, therefore, unduly

penalized in the calculation of the percentage

of dampness at the end of the test.

Table 14.

Performance of walls with stucco facings

[Heavy-rain tests]

Wall

97-1 98-2 99-3 100-4 101-5 102-6 103-7 104-8

Construction

of walls °

Eps_

Epr. Ews Ewr

Sps.

Spr. Sws_

Swr_

Dura- tion

of

test

Days

4

314

6

6

77

'> 5.3

Time to fail, as indicated byDamp

through

wall

hr 87 ±5

41 ±4

207 ±5

64 ±5

108 ±7

132 ±7

142 ±14

Leak

through

wall

hr

Area damp

at end

of

test

%

55

8

33

33

17

25

10

17

Maxi- mum

leakage per hour

Liters

0

0

0

0

0

00

0

Rating

» The designation for all of these walls is sj9A2. Key for construction symbols: E=tile set on end. S=tile set on side. p=plain stucco. w=waterproofed stucco. s=smooth texture on finish coat. r=rough texture on finish coat.

' Test on this wall interrupted by condensation on back of wall after

5.3 days of testing; no moisture penetration through the wall.

There was no great advantage in favor of any of the kinds of stucco or construction used

in the walls, as is shown below by the average

time for the penetration of moisture.

Damp through Type of wall the wall—aver- age time

Days

Stucco (plain) 4. 0 Stucco (waterproofed) 5. 7 Texture of finish coat (smooth) 5. 7 Texture of finish coat (rough) _ 4. 0 Construction (tile on end) 4. 2 Construction (tile on side) 5. 5

The data show a slight advantage for the

waterproofed over the plain stucco and the

smooth over the rough finish. Although the

data indicated a slightly greater average time

for walls of side construction than for those

of end construction, the results for the individual walls were not consistent and the least permeable wall (99-3) was of end construction. The superiority of stucco on tile walls over

similar walls faced with b brick is probably the

result of the greater imperviousness of the stucco facing. In this connection it should be

stated that because of their unfamiliarity with

the application of stucco, the masons used a

great deal of time and care in the application

of the stucco coatings.

IX. SURFACE WATERPROOFING

TREATMENTS

In order to determine the effectiveness of

waterproofing methods for leaky masora-y

walls in existing structures, several of the walls

which leaked in the permeability tests were

treated and then re tested. As the leakage

through the walls usually was through openings

in the masonry, most of the walls selected were

of workmanship B. However, as dampness

rapidly penetrated absorptive units, such as brick c and the concrete blocks, walls of workmanship A containing these units were also treated.

The waterproofing treatments may be divided

into three classifications:

1. Raking of the face joints and repointing

with mortar.

2. Filling of openings in the face of the wall

(especially in the joints) with cement-grout

or wax.

3. Painting the wail with colorless solution,

oil paint, or cement paint.

Some of the treatments were combinations of

1,2, and 3 above, and one was a molten-paraffin treatment. Each waterproofing method will be

discussed together with a comparison of the

performances of the walls in heavy rain tests before and after treatment. An outline of the

waterproofing tests that have been made to date

is contained in table 15, which gives the wall

numbers, designations, treatments, and test

ratins:s.

[23]
Table 15. —TT all treatments and test ratings

Wall Designation i Treatment

Rating

Before

treat- ment

After

treat- ment

42-AlO

44-52 8-64

10-48

32-50

34-46

57-37 60-44

92-13 40-22

77-91

43-54 41-A9

35-62

65-31

18-17 39-63 69-30

24-A7 48-A8

7-16 31-72

56-29 89-12

91-26

35-62

18- 17 39-63 69-30

7-16 31-72

19-61

36-53

37-59 20-57

71-32 9-55

78-39

38-49

32-50 41-A9

44-52 42-AlO

110-A12

111-AU

60-44

bb8B2__ bb8B4,.

aal2B2_. aal2B4.. bbl2B2.

bbl2B4.

ccl2B2__ ccl2B4_

bdl2B2_ bb8B2._ bb8B2,

bb8B3-

bb8B2_

bb8Al_

cc8Al.._

aa8Bl.__ bb8Bl._

CC8B1... bbl2Al_

ecl2Al_.

aal2Bl-_ bbl2Bl.

ccl2Bl._

bfl2A2__ bhl2B2.

bb8Al._.

aa8Bl__. bb8Bl._

cc8Bl._.

aaI2Bl.. bbl2Bl.

aa8B2._. bb8A2__ bb8A3_

aa8B3..

CC8B3-- aal2B3_

cc8B2.. bb8A4. bbl2B4-R. bbl2B2-R

.

bb8B2 bb8B4-R_

bb8B2-R_

m8A2

n8A2

CC12B4-R.

Repointed

----do-_ .--do

.-._do Repointed (2 tests made

after repointing). --._do Repointed --. --._do

._-_do Repointed and paraffin and tung-oil solution. Repointed and alumi- num-stearate solution. do Repointed and linseedoil solution.

Paraffin and tung oil solution. do

do

do

dodo

.do_

.do-

_do_

_dO- _do_

-do- Waxed joints '' do.2

do.2

do.2

do.2

do.2 Grouted joints (-Y mixture) . Grouted joints (flint morta-).do Grouted joints (highearly-strength cement

mortar)

.

dodo

Proprietary, treatment 1 Proprietary, treatment 2 Aluminum-stearate solution. Linseed-oil solution Repointed and linseedoil solution. Molten paraffin

Oil paint Cement paint do

do

VP

VP

P

VP

VP

VP

VP

VP

p

VP

^^p VP

VP

VP

FVP

VP

VP

E

GVP

VP

VP

FVP

VP

VP

VP

VP

VP

VP

VP

F

FVP

VP

P

VP

VP

G

^•p F

GVP

VP

P

GF

F

G

P,G

P,GP

P

GF

G

G

G

TP

Frp

TP

VP

E

GVP

VP

VP

GP

F,GGFP

F

F

1 Letter R after designation indicates wall was repointed and tested before treatment.

2 Walls treated with paraffin and tung-oil solution before waxing.

1. Repointing of Face Joints

Eliminating comparatively large openings in

the walls by repointing of the face joints re- quired more time and labor than any of the

other treatments. The old joints were cut out

carefully to a depth of K inch with the aid of an air hammer and then repointed with the same kind of mortar as was originally used.

The new joints were tooled with a rounded

bar and packed tightly in place so that the

construction of the walls which were origmally

of workmanship B resembled class D workmanship. The entire operation required about one man hour per square foot of wall surface. After

repointing the walls were wetted daUy and

kept in a damp location for 1 week. They

were tested not less than 3 weeks after re- pointing. Data pertaining to the performance

of the repointed walls are given in table 16. Repointing of the face joints was successful

in that the permeability of all of the walls was

greatly reduced. The performance of the re- pointed walls was much better than that of

walls built with the same kind of brick and

workmanship D. The treatment was most

effective on walls 8-64 and 10-48 built with the

low-absorptive brick a and least effective on

walls 57-37 and 60-44 constructed with the

liigh-absorptive brick, c. The permeability of

the brick c walls was not reduced as much be- cause the repointing operation did not affect the absorptive properties of the brick.

The effect of continued exposure of the new

face joints was markedly apparent in the tests on walls 32-50 and 34-46. These walls were

tested twice after repointing and both were

rated "Poor" and "Good", respectively, on the

first and second tests. The performance of

repointed walls was better in the second than in

the first test. The 8-incli walls of brick b gave

creditable performance on their first test after being repointed.

The application of two coats of aluminum

stearate solution to walls 77-91 and 43-54

after repointing, slightly reduced the permeability of these walls. The effect can be seen by

comparing these walls with the averages for walls 42-AlO, 40-22, and 44-52. The proportion by weight of the aluminum stearate solution was 4 percent of aluminum stearate to 96

percent of mineral spirits. The addition of a

small amount of paraffin to the solution applied

to wall 77-91 made little difference in the per- formance of the wall.

2. Paraffin and Tung-Oil Solution

Experiments in the waterproofing of natural

building stone ^ have shown that the applica2 D. W. Kessler, Experiments on eiierior waterproofing material for masonry, J. Research NBS 14, 317 (1935), RP771. For sale by Superin- tendent of Documents, U, S. Government Printing Office, Washington,

D. r., price, 5 cents.

[24]
tion of a solution of paraffin and tiing oil in a

volatile solvent greatly reduced the effects of

capillary attraction with very little discoloration. The solution applied to the masonry

walls was mLxed in the proportion of 10 percent of paraffin (mp 55° C) 5 percent of

tung oil (Thermolyzed) and 85 percent of mineral spirits by weight. Tlie solvent dissolved

this amount of paraffin at temperatures above

75° F.

Table 16.Performance of rvalls before and after repointing the face joints

[The data in the first hue for each wall pertain to test made before treatment]

Designation

bb8B2_

bb8B2 '

bh8B4_

bb8Baal2B2.

aal2B4_

aal2Bbbl2B2

bbl2B4

hbl2Bccl2B2_

cel2B4_

CC12Bbdl2B2

bb8B2 <

bb8B.3 <

bbSB- <

Duration

of test

Days

Time to fail, as indicated byDamp

through

wall

hr

0. 02

7. 8 ±.5

0. 05

5.7 0.01

.50

0. 03 4.7

2.2

19 ±3

0. 17

41 ±6

1.2 30

0. 10

2. 2

13. 1 ±. 1

0. 12

3

17. 2 ±.3

0. 10 2.6

15

0.20

8 ±1

0. 27 3.5

0.23

6

0. 38

75 ±2

0.03

10 ±2

0. 25

4

0. 03

Leak

through

wall

0. 02

0. 03

0. 13

I ±5

0. 12

I ±5

1.5

13

0. 82

4.5

2.6

0. 03

.07

0.05

Leak

through

facing

0. 02

0. 06

0. 03

10.3

0. 04

0.05

.67 18 ±3

0. 02

1. 5

0. 03

1.

1

0. 13

2. 6 ±. 4

0. 23

2

0. 18 2.3

0. 12

15 ±4

0.05

0.05

Area damp

at end of

test

10022

10057

10075

100

51

10043

10 10055

1

10049

d 25 d45

10025

10018

]00

in

Maximum leakage

])er hour

Through

wall

Liters

17

0150

380.5

230

0.5

.5

0

0.5

0

0.6

0

6

0 42

0

Through

facing

Liters

34

036

0

210.3

30

0

140.3

160

36

20.1 38

2.0 0

100

370

3

85

3

670.08

440

55

0

» Two coats of paraffin and tung-oil solution applied after repointing.

!> Second test on repointed wall.

" Two coats of aluminum-stearate solution applied after repointing.

<i Not flashed.

The walls were in a dry condition before

the application of two coats of the solution on

consecutive days. The liquid was applied

liberally with a brush until the surface was

wetted and the solution was no longer absorbed

quickly. The high-absorptive brick c walls were not saturated, but the liquid was applied

until the joints were wet. The walls absorbed

about one-half as much of the solution on the

second application as on the first. The approxi-

[25]
mate coverino; capacity of the solution for the

different brick surfaces is given below.

Covering capacity of paraffin and tung-oil solution (square feet per gallon)

Brick One coat Two coats

a 123 85

b 36 21

c 12 9

After the application of the solution, the walls were stored for at least 2 weeks before testing

to permit the volatile spirits to evaporate and

the tung oil to oxidize. Data on the performances of the walls before and after treatment

v/ith paraffin and tung-oil solution are given in

table 17.

Wall

35-G2

65-31

18-17

39-63

69-30

24-A7

48-A8

7-16

31-72

56-29

89-12 '

91-26 =

3. Joint Filling

The time and labor required to repoint the

face joints of a wall made it desirable to investigate the effects of filling the openings in joints

that were otherwise structurally sound. Two

The application of a tung-oil and paraffin

solution had little, if any, effect on the permeability of walls that leaked badly. The solution was somewhat effective when used on w^alls that had been penetrated by moisture through

capillarity. All of the walls (both treated and

untreated) gradually became less permeable as the number of tests increased and it is difficult to determine how much of the improvement

noted for some walls in table 17 can be credited

to the use of the paraffin and tung oil. The application of the waterproofing to brick

c and workmansliip A (walls 65-31 and 48-A8) was beneficial, but it did not improve the rating

of these walls. It is possible that if the brick

had been saturated, or if more tung oil had been

added to give the solution greater "body" the

treatment would have been more effective.

-J Rating

4 VP

i VP

F

FVP

VP

VP

VP

VP

VP

E

E

G

GVP

VP

VP

^'p VP

rp

F

0VP

P

kinds of ffiling materials were used, a wax, and

finely divided cementitious mixtures. The

tests on walls containing wax as a filler are described and referred to as tests on waxed

joints; those containing cementitious mixtures,

as grouted joints.

Table 17.Performance of ivalls before and after treatment with paraffin and tung-oil solution

[The data in the first line for each wall pertain to test made before treatment]

Designation Duration

of test

Time to fail, as indicated byDamp Leak Leak

through through through

wall wall facing

hr hr hr

0. 01 0.01 0. 25

.05 .40 .52

.47 15 ±6

3.6 14 ±6

0.03 0. 03 .08

. 13 . 13 .20

.02 .05 .03

.93 . 13 .02

.10 . 12 . 15 .27 .38 .50 42 ±4

9 ±2

18 ±5

0. 10 0. 10 0. 15 .36 1 1 .03 0. 07 0. 02

.63 4 . 10

. 17 0. 33 . 13 1.4 15 ±4 2.2 0.50 0. 75 4 5.5

0. 22 .22 0. 07

5. 5 .67

Area damp

at end of

test

Maximum leakage pc hour

Through

wall Through

facing

bbSAl.

CC8A1..

aa8Bl__

bb8Bl_.

cc8Bl__

bbl2Al

ccl2Al_

aal2Bl.

bbl2Bl

cel2Bl.

bfl2A2_

bhl2Bl

Days

11

1

1

1

1

1

1

0.1

12

1

1

10.3

1

1

1

1

1

1

100

100 100

8185

53

100

100 100

100

16 "44

65

5375

k 50

10076

2520

50

55

Liters Liters 20 0. 40.9 0

.03 0

11 9

13 4

1 120

2 78

11 77

11 40

0 0

0 0

0 0

0 0

li 10

13 1 0.3 158

. 1 46

. 5 40

.3 43

» 11 percent damp at end of first day. b 50 percent damp in 0.3 day. • Not flashed.

[26]
(a) Waxed Joints

The wax used on the walls was made by

mixing equal parts by weight of paraffin and

tung oil. It was applied to some of those walls

that had been treated with the paraffin and

tung-oil solution. After applying the wax

with the finger tips the joints were wiped gently

with a cloth in order to pack the wax in place

and to remove the excess. The joints were made lighter in color and they were accentuated

in jagged lines as though snow or ice was en- crusted upon them, presenting a markedly

altered appearance. The average amount of wax used was about 4.5 pounds per 100 square

feet of wall surface. Data pertaining to the

results of tests on walls with waxed joints are

g-iven in table 18.

Table 18.Performance of walls before and after joint treatment

[The data in the first line for each wall pertain to test made before treatment] Time to fai', as Maximum leakage

indicated by- per hour Duration

of test

Leak Area damp

Wall Designation through at end of Rating

Damp

through

wall

Leak

through

wall

facing test Through

wall Throughfacing

Walls With Waxed Joints

[Walls treated with paraflBn and tung-oil solution and tested before waxing]

35-62

18-17

39-63

69-30

7-16

31-72

bbSAl.

aa8Bl_.

bb8Bl_

CC8B1..

aal2Bl.

bbl2Bl

Days

0.3

1

hr hr hr % Liters Liters

0, 0.5 0. 40 0. 52 100 4 0.4 VP

3 56 0 0 F

12 ±1 10 0 0 G

0. 13 .13 .20 53 13 4 VP

24 7 0 0 G

0.03 .13 .02 100 2 78 VP

3. 5 2 78 0 0.6 F

0.27 .37 0.50 100 11 40 VP

2. 1 ±. 1 10. 7 ±1.7 67 0 1.4 P

0. 35 1 1 53 13 1 VP

4. 4±. 1 8. 6 ±. 9 7. 5 ±.5 33 0.9 0.5 F

0. 53 4 0. 10 50 .1 46 VP

7 ±.7 15 18 0 0. 3 F

Walls With Grouted Joints

aa8B2_.

bb8A2_

bb8A3_

aa8B3..

cc8B3_.

aal2B3

1 0.05

2 27 ±1

1 0. 02

1 3.4

1 0. 02

1 4

1 0. 10

3 40 ±6

0. 1 0. 15

1 .83

1 1 4 91 ±3

0. 32 0.03

.08

.05 4.5

.01 0.03

.22 .28

2 15±6 0.07

80 0.5 20 VP

40 0 0 G

100 .9 0 F

52 0 0 F

100 .7 . 1 F

35 0 0 G

95 .8 19 VP

0 100 0 0 G

100 12 17 VP

100 0 2 P

70 .5 14 P

21 0 0 G

a Wall wasrepainted with 2 coats of paraflSu and tung-oil solution after completion of test on waxed joints.

^ Joints filled with mixture X by representatives of a contracting company.

" Joints filled with grout of cement and flint.

<i Joints filled with grout of high-early-strength cement, flint, and sand.

• Some dampness probably caused by condensation.

The performance of the walls was improved

by waxing the joints, the average rating being

increased two grades from VP to F. Wall

69-30, built of the high-absorptive brick c was

benefited less than walls built of brick a or 6. The openings in the joints of wall 35-62, workmansliip A, were closed by waxing, which changed

the rating from VP to F. Tliis wall was later

treated with an additional coat of paraffin and

tung-oil solution and the performance was

raised from a rating from F to G. It appears,

therefore, that the best method of applying

paraffin and tung oil in the form of both a wax

and a solution is to apply the first or second

coat of the solution after application of wax to the joints. It is possible that suction of the

[27]
solution into openings not perfectly sealed by

the wax, followed by a brushing over of the wax,

makes the wall less permeable.

(6) Grouted Joints

The cementitious joint filling materials used were a proprietary mixture of unknown composition and two mixtures prepared at the

Bureau. The proprietary mixture designated

as "A"" was donated and applied to wall 19-61

by representatives of a contracting company.

After wetting the face of the wall, the A' mixture was mixed with water and vigorously

brushed into the joints. The bricks were then

cleansed with a damp sponge. The wall was

cured by wetting daily for 1 week.

The joints of walls 36-53 and 37-59 were

fUled with a mortar composed of equal parts by

weight of Portland cement and powdered flint. The material later used on walls 20-57, 71-32,

and 9-55 was mixed in the following proportions

by weight: 40 percent of liigh-early-strength

cement; ^15 percent of powdered flint, 96 per- cent passing a No. 200 sieve; and 45 percent of

Potomac River building sand, passing a No. 30

sieve. These materials were applied to the walls in

much the same manner as in the application of the Xmixture to wall 1 9-6 1 . Water was added

to the mixtures until they reached a thick

creamy consistency. After wetting the wall

surface, the mortar was applied to the joints

with a typewriter cleaning brush. The weight

of dry material required for 100 square feet of wall surface was about 5 pounds for the flint mortar (tooled joints, workmanship A) and

10.5 pounds for the liigh-early-strength cement,

flint, and sand mortar (cut joints, workmanship B). The difference was largely a result of the rough texture of the joints in workmansliip

B. An average of 2 hours' time was required to apply the joint flUing to a wall of workmanship

B having an area of 13.5 square feet. The

results of tests on walls with grouted joints are

also given in table 18. The grouting of the joints greatly reduced the

permeability of the walls. The treatments

given walls 19-61, 20-57, and 9-55 were ex3 Donated by International Cement Co

ceptionally effective. The data in tables 16,

18, and 19 showed clearly that repointing or fill- ing of the joints with wax or grout stopped large

leaks, but did not prevent the penetration of moisture through walls of liigh-absorptive

brick.

4. Special Proprietary Treatments

Representatives of one of the governmental

agencies requested a contracting company

specializing in waterproofing treatments to apply their treatments to two of the walls. WaU 78-39 (cc8B2) was given treatment 1 by

representatives of the contracting company as

follows: After testing the face joints of the wall

with a sounding tool and judging them satis- factory, the joints were filled with mixture A'

as previously described. The next day a solution of 12 fluid ounces of paraffin in 108 fluid ounces of mineral spirits (Varsol) was prepared

and applied to the wall. The flrst coat was

applied with a brush. This was foUowed by

a liberal application with a brush and an air blower. The air blast was directed upwards,

spreading the liquid over the wall surface and

preventing it from running down the face of

the wall. The remainder of the solution was

then brushed on the wall, and rough spots in

the surface were then filled with a small quantity of paraffin and tung-oil wax. This wax

was melted in place on the wall with a hot air blast. A block of paraffin wax was then

rubbed over the brick and the adhering wax

was melted with the hot blast. About 2 ounces of paraffin was applied in this manner

and the total amount applied to the wall

(area 13.5 ft.^) was about 0.8 pound. Thus,

there were three waterproofing operations made

on this waU: filling of the joints, the application of a paraffin and tung-oil solution, and

finally, the application and melting into place

of cold paraffin wax. The appearance of the

wall after these operations was not greatly

altered although the film of paraffin on the

brick could be scratched with the fingernail.

The effect of treatment 1 on wall 78-39 was

exceptionally good and the results indicate that

it is possible to waterproof high-absorptive

brick walls 8 inches thick and of class B workmanship.

[28]
Table 19.

Performance of walls before and after treatment with various waterproofing materials

[The data in the first lino for each wall pertain to test made before treatment]

Duration

of test

Time to fail, as indicated byAreadamp

at end of

test

Maximum leakage per hour

Wall Designation Damp

through

wall

Leak

through

wall

Leak

through

facing Through

wall Throughfacing

Rating

Special Proprietary Treatment 1

78-39 CC8B2.

Days

f 0.

2

1 2

hr0.08

9 ±1

hr

0. 18 hr0. 18 %100

a 26

Liters

10

Liters66

0 VPG

Special Proprietary Treatment 2

38^9 bb8A4 __ { \

0. 05

.75

0. 05 0. 38 100

b 67

200. 5 0 VP

G

Walls Treated With Aluminuni-Stearate Solution

34-4S < bhl2B4-R

{ \

17. 2 ±. 3 158 ±71

1 0

0 00 GE

Walls Treated With Linseed-Oil Solution

32-50

41-A9

c bbl2B2-R

{ \

{ \

13. 1 ±. 1 12 ±.6

0. 02

8 ±1

18 ±3

200.08

1012

100

10

00

450

0.

1

. 1 110

G

G

VP

G

d bb8B2 0.02

Walls Treated With Molten Paraffin

44-52 c bb8B4-R

{ 1

0. 58

5. 1 9±1 12 7510 0.5 0

0.3

0 r

G

» 12 percent damp first day.

35 percent damp first day. Repointed and tested before treatment,

d Repointed and painted with 2 coats of linseed-oil solution before testing.

Treatment 2 of the contracting company was

applied to wall 38-49 (bb8A4). The wall

joints were sounded and judged to be satis- factory. A mixture was then prepared using

5 fluid ounces of molten paraffin, 5 fluid ounces

of tung oil, and 70 fluid ounces of mineral

spirits. All of this solution was applied to the

wall with a brush and a "cold air" blast (air

temperature about 80° F). The face of the

wall appeared to be saturated. About 7 ounces

of wax made of paraffin and tung oil was then

rubbed into the joints and melted with a hot

air blast. Excess of melted wax was dis- tributed over the brick with a cloth. The wax

altered the appearance of the wall considerably,

the white parafiui outlining the joints in jagged

lines. The results of tests on these treated

walls are given in table 19. Treatment 2 on wall 38-49 was efl'ective in

that the rating of the wall was raised from

VP to G. The results are, however, about the same as those obtained on similar walls by

either waxing or grouting the joints. Considering the kind of brick and workmanship

together with the labor and materials used,

this treatment was not as effective as that given

to wall 78-39.

5. Aluminum-Stearate Solution

Data relative to the effectiveness of aluminum-stearate solutions are given in table 16

for \valls 77-91 and 43-54, and in table 19 for waU 34-46. Walls 77-91 and 43-54 were re- pointed and treated with aluminum-stearate

solutions and the data in table 16 shows that

these walls were only slightly less permeable

than similar ones which were repointed but

not treated with aluminum stearate. Wall 34-

46 was pointed and tested (see data in table 15)

before treatment with a solution containing 4

[29]
percent of aluminum stearate and 96 percent

of mineral spirits by weight. The results of

the tests (see data in table 19) show that this

wall gave a better performance after treatment

with the solution than before, but, since re- peated tests on repointed walls indicate a progressive decrease in permeability, it is not

known how much of the improvement in per- formance resulted from the aluminum-stearate

treatment. The aluminum-stearate solution has been

applied only to walls of low permeability (walls

having a rating of F or G) and the performance

of these walls has been improved, but it is not known whether the solution would be

effective if applied to leaky walls having ratings

of P or VP.

6. Linseed-Oil Solution

Two repointed walls were treated with lin- seed-oil solutions. The effects of the linseedoil treatment alone were determined for one

wall, and the combined effects of repointing

and the oil treatment were determined on the

other. The linseed-oil solution was mixed in

the proportion by weight of 20 parts of kettlebodied linseed oil, 20 parts of turpentine, and 1 part of paint drier. Two coats were applied

to each wall, one coat on each of consecutive

days. The covering capacity of the solution was 114 square feet per gallon for one coat and

67 square feet per gallon for two coats. The

solution dried to a hard gloss, darkening the wall

sKghtly and bringing out the colors of the bricks.

When first exposed in the heavy-rain tests the

water ran off the wall in separate streams. After about 3 hours of exposure the face of the

wall became wetted, the water ran down in even flowing sheets, and the appearance of the

wall was lightened and clouded by a change in

the condition of the waterproofing. At the end

of the test the face of the wall was covered with

a sticky opaque film. After drying, the face of

the wall resumed its original color, but the

gloss had disappeared from the oil coating.

Data pertaining to the results of tests on walls

with linseed-oil coatings are given in table 19. The treating of wall 32-50 with linseed-oil

solution did not change the performance of the

wall. The results of these tests and those of

walls treated by the contracting company

indicate that treatment of the brick h is of httle

benefit after the face joints have been made

watertight.

The combined repointing and linseed-oil

treatment of walls 41-A9 was eft'ective, however. Tliis repointed wall gave a better per- formance than similar walls of the same brick

and workmanship. It is probable that the

linseed-oil solution reduced the permeabilit}'

of the new face joints.

7. Molten Paraffin

Wall 44-52 (bb8B4-R) was coated with molten

paraffim. The paraffin was heated and brushed on the face of the wail while at a smoldng-hot

temperature. The liquid was partly absorbed

by the wall surface and cooled as a very thin,

almost invisible coating. About 5 pounds of

parafl&n was applied per 100 square feet of wall

surface. Very good results were obtained with

the paraffin treatment as is shown by the data

given in table 1 9 . There was no leakage through

the wall and the amount of damp wall area at the end of 1 day was only 10 percent.

8. Paints.

The eft'ectiveness of one type of oil paint and

one kind of cement paint was investigated.

(a) Oil Paint

An oil paint designed for use on masonry

walls was ground and mixed at the Bureau from

materials commonly used in paint manufacture. The proportions by weight of the materials used in this paint were as follows:

Pigment (68%) Liquid (32%)

55% of basic carbonate

white lead. 25% of acicular type zinc

oxide. 10% of titanium oxide 10% of magnesium silicate^

30% of "Thermolyzed"

tung oil. 20% of kettle-bodied lin- seed oil. 28% of mineral spirits. 17% of turpentine, 5% of liquid paint drier.

Two coats of this paint were applied to wall

42-AlO (bb8B2 repointed). Two days were

allowed between the application of the first and second coat. The covering capacity of the

[30]
paint as applied on wall 42-AlO was 320 square

feet per gallon for the first coat, 380 square feet per gallon for the second coat, and 170 square

feet per gallon for the two coats. Data on the results of the test given at the

top of table 20 indicate that this paint was

exceptionally effective. Before painting, dampness penetrated the wall in about 7.8 hours and

22 percent of the area of the back was damp

after an exposure of 1 day in the heavy-rain

test. After painting, the wall was exposed for

8 days without dampness appearing on the

back. When the painted surface was first ex- posed it appeared to be water repellent, but

after 3 days of exposure the face of the wall was

wet over nearly the entire surface. At the conclusion of the test the paint dried quickly. It was hard and firm to the touch, but the paint

had lost some of its "egg shell" gloss and there was some blistering at a few of the cross joints.

Table 20.

Performance of walls before and after applying oil and cement paints

[The data in the first line for each wall pertain to test made before treatment]

Wall Designation Duration

of test

Time to fail, as indicated by

.\rea damp

at end of

test

Maximum leakage per hour

Rating

Damp

through

wall

Leak

through

wall

Leak

through

facing

Through

wall Throughfacing

Oil Paint

42-AlO «bb8B2-R

Days

18

hr

7. 8 ±0. 5 hr hr %22

0

Liters

0

0

Liters

0

0 aE

Cement Paint

110-A12

111-All

60-44

b m8A2

{ I

{ ^

{ \

0. 02

161 ±10

0.05

2. 9

0. 75

3. 5

0. 02 100

3

70

16

28

35

0

VP

E

VP

G

GP

E

b n8A2

.05

« CC12B4-R 2 0

0

3

0

» Repointed and tested before treatment.

» Not flashed.

" 100 percent damp in 0.7 hour.

<i Second test of painted wall.

Since the water was applied only to the ex- posed or painted face of the wall, the test is no

criterion of the durability of an oil paint on a masonry wall in those cases where moisture

penetrates behind the surface through faulty

flashings or by other means.

(6) Cement Paint

The cement paint used on the walls was

mixed in the proportion of 40 percent of white

Portland cement and 60 percent of water by

weight. A commercial ammonium stearate was

added in amount equal to 0.2 percent by weight

of the cement. The wall surface was dampened

to reduce the suction and two coats of paint were applied with an interval of 2 days between

the application of the first and second coat.

The paint surface was cured by storing the

wall in a damp room and wetting daily for 1 week. The covering capacity of the paint on

the wall surfaces is given below

:

Wall Designation

Covering capacity

Cement (sq ft per sack) Paint (sq ft per gal)

First coat Second

coat Twocoats

First coat Second

coat Twocoats

110-A12 m8A2 1, 020

660

2, 670 740 49 124 36 Ill-All n8A2 2,470 520 32 119 25 60-44 CC12B4-R... 1,030 3, 070 770 50 149 37

The rough texture of the cinder concrete block in wall Ill-All made it necessary to apply nearly 50 percent more paint to this wall

than was used on the surface of the stone concrete block (110-A12). Test data showing the

[31]
results of treating the walls with cement paint

are given in table 20. The cement paint waterproofing was very

effective on walls 110-A12 and wall 60-44, both

walls being given a rating of excellent after painting. Although the rating of wall 1 1 1-Al 1 was improved from very poor to good, the wall was penetrated by moisture in 6 or 7 hours.

It is probable that air holes were present in the

paint film despite the fact that more paint was

applied to this wall than on the others. A

second test was made on wall 111 -A11 and the

performance, while rated as good, was inferior to that shown in the first test made after painting.

X. SUMMARY

1. Definitions

The definitions of some of the terms used in

the conclusions o.re as follows: Capillarity test. —Water was applied near the

top of the wall in amount sufficient to cover the

wall face with a thin unbrolven sheet. This

test was the first applied to each wall. Heavy-rain test. —Same as capillarity tests ex- cept that face of wall was exposed to an air pressure of 10 pounds per square foot producing

a pressure gradient within the wall from face to back.

Light-rain test. —Same as heavy-rain test ex- cept that the water was applied to the wall by means of atomizers in amounts equivalent to 0.2 inch per square foot of wall surface per

hour.

Class A workmanship.—All interior joints of the wall filled with mortar. Face joints tooled

with rounded steel bar. Class B workmanship.—Workmanship com- monly used for contract construction. Interior

joints of the wall were open and a minimum

amount of mortar was used. Face joints were

cut.

2. Conclusions

Most of the new walls given repeated per- meabihty tests of the same kind showed a slight

decrease in permeabihty with successive tests. With an air pressure of 10 pounds per square

foot (heavy-rain test) the average time required

for moisture to penetrate the brick walls of worlmianship A was one-eleventh of that without pressure (capillarity test); for brick walls

of workmanship B, it was one-sixth. The time

for leakage to start was reduced more, averaging

only one-twentieth for brick walls of workmanship B.

The average time for dampness to penetrate

brick walls of workmanship B with the lightrain tests was about 50 times as great as in the

heavy-rain tests; the time for leakage to start was about 200 times as great. The number of light-rain tests was relatively small and they were made only on the more permeable walls. Workmanship affected the permeability of the

walls more than any other factor. Walls with

tooled joints were less permeable than similar

wall with cut joints; but the quality of the

workmanship inside the walls had a greater

influence than the kind of surface finish on the

joint.

The eft'ect of wall thiclmess on the relative

permeability of 8- and 12-inch brick walls was

such that it usually required more than 50

times as long for moisture to penetrate the

thicker walls of workmanship A, and six times

as long for the penetration of 12-inch walls of workmanship B.

The absorptive properties of the brick had

a greater eft'ect on the permeability of walls of

workmansliip A than on walls of workmanship

B. The least permeable walls of workmanship

A were those built with the low-absorptive

brick. The kind of brick had little effect on

the permeability of walls of workmanship B,

but walls of this type built of the high-absorptive brick required a slightly longer period of time before penetration. The low-absorptive

brick had a tendency to "float" (settle and slip)

during construction of walls, particularly those

walls of workmanship A. The excessive brick

suction between dry high-absorptive brick and

the mortar made it difficult to align or level the facing courses. The permeability of similar walls built with

mortars having a high water retentivity (flow

after suction ranging from 87 to 109%) was

not greatly affected by differences in the relative

amounts of cement and lime. Although the

workability of all of these mortars were equally

acceptable to the masons, walls built with the

high-cement, low-lime mortars were slightly

less permeable.

[32]
The use of a lime of low plasticity producing

a mortar with low water retentivity greatly in- creased the permeability of the walls. This

effect was more pronounced when the mortar was used with high-absorptive brick.

A high brick suction resulting from the use

of absorptive brick in a dry condition increased

the permeability of the walls; in general, the

lower the absorption of the bricks at time of laying, the less permeable the masonry.

The use of two-thirds blind headers had little effect on the permeability of the walls. Walls with a high-absorptive brick backing

and a low-absorptive brick facmg were less permeable than walls of either all high- or all low-absorptive brick for: Class A workmanship

in the heavy-rain test and class B workmanship

in the light-rain test. Walls with limestone sills or belt courses of workmanship A and a backing wythe of brick were only slightly more permeable than walls

without limestone sills. Brick walls 4 inches thick with a }^-inch

mortar parging on the back were about equally

as permeable as 8-inch brick walls of workmanship A.

Walls with a brick facing and a backing of

structural clay tile were slightly less permeable

than all-brick walls for workmanship B. For

workmanship A the walls with the tile backing were somewhat superior in the capillarity test and inferior in the heavy-rain test to otherwise

similar all-brick walls. Walls of concrete masonry units without

brick facings and of class A workmanship were

very permeable.

Walls with a structural clay tile backing and

a stucco facing were less permeable than walls

faced with a medium-absorptive brick. All of the joint treatments such as repointing,

grouting, or filling the joints with a paraffin wax

were effective in stopping leakage tlirough openings in the face joints.

The application of colorless waterproofings was ineffective in stopping leakage through

openings in the joints.

Although joint treatments reduced the leakage through walls of high-absorptive brick, the

penetration of moisture through the header

brick of walls 8 inches thick, made it necessary

to waterproof these brick for satisfactory wall

performance.

Molten paraffin, oil paint, and cement paint were effective waterproof coatings.

XI. APPENDIX

Review of Previous Investigations

Although the problem of dampness in masonry walls and the related subjects of efflorescence, bond of mortar

with masonry units, and durability of masonry have

been discussed by many authors, only a few of these have presented data showing the results of waterpenetration tests of masonry panels. In the following

review of the literature pertaining to water penetration in masonry, only those publications are cited which

describe investigations of the permeability of walls of several different materials and constructions.

1. Tests at Mellon Institute ^

The investigation included permeability tests of about 300 masonry panels. The panels were erected outdoors under conditions simulating those which exist

in actual construction, and were built under careful supervision. The absorption of the brick when immersed flatwise in water to a depth of Ys inch for 10 minutes varied from 0.6 to 12.0 percent by weight.

More than 20 different mortar mixtures were used, in- cluding masonry cement mortars as well as those containing mixtures of cement and lime. After aging, the

panels were tested for permeability by spraying water

over the exposed faces. Although no results of the per- meability tests are tabulated, it was reported that walls one brick in thickness leaked during hour of exposure

to the spray. Panels having an air space between the

brick facing and the backing did not permit leakage

completely through the wall. The papers include a

comprehensive discussion of the effects of design,

qualities of materials, and workmanship on the per- meability of masonry walls.

2. Tests at the National Bureau of Standards

In two investigations at the National Bureau of Standards some of the factors affecting the rate of travel

of moisture through brick and mortar and the permeability of masonry were studied. In the first investigation 2 the rates of water penetration through solid brick and mortar, both singly and in combination, were

studied. It was found that the penetration of water was much slower in the brick-mortar assemblages than

in either of the two materials singly, there being a re- tardation in the rate as the moisture traveled from one

material to the other.

1 F. 0. Anderegg, Comtruction of watertight brick masonry, J. Am.

Ceram. Soc. 13, 351 (1930); F. O. Anderegg, Watertight brick masonry,

Archt. Record 70, 201 (1931).

2 L. A. Palmer, Water penetration through brick-mortar assembages.

J. Clay Prod. Inst. 1, 19 (1931).

[33]
In the seconrl investigation,' permeability tests were made on 240 wallettes of brick masonry 8 inches thick, 4 courses high, and about 17 inches long. Eighty

groups of these specimens were made, using 10 differ- ent mortars and 5 makes of brick. The two bricks of lowest absorption were laid without wetting. The other

three types were used both in the dry condition and

after immersion in water.

All joints were filled solidly with mortar. The exteriors of the joints were cut flush with the sides of the

wallettes. When the specimens were 3 months old, they were turned to cause the vertical faces, as constructed, to be uppermost and horizontal. They were

tested for permeability by confining a pond of water 1 inch deep on the upper surfaces. The number of leaks, their location, the elapsed time before they appeared

and the rate of leakage were observed. The observations indicated that the leakage occurred through the joints rather than through either the solid brick or the mortar. Seventy-three percent of the total number of leaks in the wallettes appeared at the junctures of the vertical and horizontal mortar joints. The

time for leakage and the rate of leakage were controlled

largely by both the rate of absorption of the brick at the time of laying and the water retentivity of the mortar. In general, specimens built with high-absorptive brick

laid dry were more permeable than those constructed with the same brick after wetting. The leakage

through specimens of brick containing cracks was

considerably greater than that through specimens of other bricks having similar physical properties.

3. Tests of the Louisville Cement Company <

Permeability tests were made on about 50 small reser- voirs of brick masonry, each six courses high and about

25 inches square on the outside and having walls 8 inches

thick. The water absorption by the 24-hour immersion

method of the eight makes of brick used ranged between

3.4 and 14.0 percent. Four different cement-lime

mortars, one lime mortar, and one masonry cement

mortar were used. At least one specimen of each combination of brick and mortar was constructed. The

joints in the specimens were slushed full of mortar so that all cross and collar joints were well filled. Face

joints on the inside of the tanks were struck and those on the outside were cut flush with the brick surfaces. When 30 days old, the reservoirs were filled with water and observations of leakage were made for 48 hours. The reservoirs which leaked did so almost immediately, indicating that the water passed through openings rather than through solid portions of the bricks or mortars. Although there was a tendency for the leakage to be greater for the reservoirs built with the more absorptive brick (presumably dry when laid), some

of the specimens of highly absorbent brick gave good

performance. The kind of mortar used did not affect the permeability of the masonry.

3 L. A. Palmer and D. A. Parsons, Permeability tests of 8-in. brick

wallettes, Proc. Am. Soc. Testing Materials 34, pt. II. 419 (1934).

* J. H. Mallon, Leaky brick walls, Archt. Record 72, 412 (1932).

4. Tests of the Alton Brick Company ^

Small tanks, 21 inches square on the outside, six courses high, and with walls 4 inches thick, were tested

for water permeability. Six makes of brick and 9 mortars were used in the construction of about 30

specimens, each representing a combination of 1 kind of brick and mortar. The absorption of the bricks ranged

between 2.6 and 10.8 percent by the 48-hour cold-water immersion test. All bricks were laid dry except two

varieties of drj'-press brick used in the construction

of two tanks. The bed joints were furrowed and the

cross joints were completely filled by slushing. The

joints on the inner surfaces of the tanks were tooled, while those on the outside were cut flush. After the tanks had aged for 1 month they were tested by filling with water. The performance of the tanks during the tests was

rated according to the number and approximate size of the leaks. The leaks were through openings in the

joints and not through the bricks or solid mortar. The

permeability of the tanks was found to be dependent

upon the absorptive properties of the bricks, irrespective

of the kind of mortar used. Specimens containing

dry-press brick laid wet gave better performance than

similar ones of the same brick in which the brick were

laid dry. The kind of mortar used did not affect the permeability of the specimens. The paper includes an

excellent digest of the literature on the factors affecting the permeability of brick masonry and includes a

bibliography.

5. Tests of the Portland Cement Association '

Walls 32 inches wide by 48 inches high were constructed and tested under conditions simulating winddriven rains. The 45 specimens contained various types of concrete masonry units and mortars. They

were tested in a vertical position by exposing them to a wind of 25.3 miles per hour and a water spray equivalent to a rain intensity of 2]?^ to 3 inches per square foot

of wall surface per hour during the first 12 hours of the

test, after which the intensity was increased to a rate of 12 to 14 inches per square foot per hour. The per- formance of the specimens during exposure was judged

by visual examinations supplemented by electrical resistance measurements. Leakage in the base walls of concrete units took place

through the mortar, through the joints between mortar and masonry unit, and through the concrete of the masonry units. The penetration through the face

shells was caused largely by the dynamic action of the wind and rain, while that through the interior and back was by capillary absorption. The initial penetration

of the face shells usually occurred in 5 minutes or less and proceeded with such rapidity that pools of water

soon formed in the cores at the base. Dampness on

' Impervious brick masonry. Pamphlet, Alton Brick Co., St. Louis, Mo. (1933).

* R. E. Copeland, C. C. Carlson, Tests of the resistance of concrete masonry walls to the penetration of rain, Proc. Am. Concrete Inst. 32, 485 (1936).

[34]
the back face was noted in from 10 minutes to 1 hour. Usually the leaks occurred first at the joints, but these were followed closely by dampness on the shells, es- pecially with the more porous concretes. After the walls had been tested for permeability, some were given a facing treatment of either portland- cement paint or stucco. The paint consisted of a mixture of white portland cement, a small amount of water repellent, and water. The paint was applied by means of stilT brushes except for one wall which was

given spray coatings. None of the 8-inch walls which

had been given two brush coats of cement paint showed

leakage through the back face. The minimum time

for initial penetration of the face shell for these was 2 hours and 45 minutes and usually 4 hours or longer was

required. The wall with two coats of sprayed-on

paint developed face-shell penetration in 25 minutes and

showed dampness on the back face at 45 minutes. One

wall with three coats of portland cement stucco showed

no sign of face-shell penetration after 219 hours of con- tinuous testing.

Washington, July 12, 1938.

O

[35]
i
The National Bureau of Standards was established by act of Congress, approved

March 3, 1901, continuing the duties of the old OflB.ce of Standard Weights and Measures

of the United States Coast and Geodetic Survey. In addition, new scientific functions were assigned to the new Bureau. Originally under the Treasury Department, the

Bureau was transferred in 1903 to the Department of Commerce and Labor (now the

United States Department of Commerce). It is charged with the development, construction, custody, and maintenance of reference and working standards, and their intercomparison, improvement, and application in science, engineering, industry, and commerce. SUBJECTS OF BUREAU ACTIVITIES

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