Moisture penetration of brick masonry panels

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Publisher’s version / Version de l'éditeur:

ASTM Bulletin, 249, pp. 39-43, 1961-02-01

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Moisture penetration of brick masonry panels

Ritchie, T.; Plewes, W. G.

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S e r

TH1

N21r 2

no.

118 c .

2

3me

NATIONAL

RESEARCH

COUNCIL

CANADA

DIVISION OF BUILDING RESEARCH

d&j,

MOISTURE PENETRATION OF BRICK MASONRY P A N E L S

BY

T. RlTCHlE AND W. G. PLEWES

REPRINTED FROM

AMERICAN SOCIETY FOR TESTING MATERIALS BULLETIN NO. 249

OCTOBER 1960,

P.

39

-

43

RESEARCH PAPER NO. 1 1 8

O F T H E

DIVISION OF BUILDING RESEARCH

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N a t i o n a l Fksoarch

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Moisture Penetration of

Brick

Masonry Panels

By T. RlTCHlE and W. G. PLEWES

A N A L Y Z E D

R a i n oenetration of brick

masonry walls has been a problem with many buildings in Canada. I t is most frequcnt in areas such as tlic Atlantic provinces, which have prolonged rain- storms, but i t is not uilcominon in interior regions. i\iIany buildings affected by rain penetration have been cxa~nined by nlc~llbers of tllc Division of Building Research of the National Research Council, and a survey of the extensive literature dealing with the

subject has been prepared (I).'

Laboratory studies of soille of the factors contributing t o the problem havc bee11 undcrtaken using a n appara-

tus for dcternlining the resistance to

moisturc pcnctration of large brickwork pancls based on t h a t dcvclopecl in the

National Bureau of Standards (2, 3).

This paper clescribes the apparatus and the results of sonlc initial tcsts of panels made of soveral types of bricks and two 1110rtars.

T e s t Method

Paiirls about 3*

ft

miclc and 4 ft

high were colistructed by an expcrienccd bricklayer alicl allo~vccl t o curc before being used in the n~oisturcb pcnctration tcsts. The apparatus, Fig. I , con- sistccl of an air-pressure c h a l ~ ~ b c r :~nd a mheclcd frame carrying thc test pancl, n~hich coultl be nlovecl into position aiicl tightly sealed in plncc agai'nst thc chanlber t o for111 onc sitlc of it. 13y ~ ~ u n ~ u i n e air into the chnmbcr a n air-

.

. -

prcssnre cliffcrencc was nlaintainccl

across thc pancl to givc the effcct cf

wind blowing against thc wall of a building. Watcr from a horizontal pipc placed near t h e top course of bricks \vas sprayed from holes spaced aloilg i t s length so t h a t snlall strcams

of ~ a t c r spread ovcr thc surfacc of

the panel in a film.

Water was pumped th1.oug11 t h e flow

nlcter to the horizontal pipc, across tlic facc of the panel, and deflected a t t h c I ~ a s c of t h e psncl back into the watcr supply tank t o bc pumped t o the panel again. Air urns supplicd t o the

NOTE-DISCUSSION OF THIS PAI'EH IS INVIT.ED, e ~ t h e r for pul~liaat,ion or for the a t t c n t ~ o r ~ of the author or u~~t,hors. Ad-

dress all conlm ilnical ions to ASTI1 I-Ieatl quarters, 1910 Racac: St,., Philatlell,l~i:t 3 . 1%.

1 Tllc boldface numbers in parelltheses

refer to the list of references apper~ded to this paper.

Large brick masonry panels of several types of bricks and two mortars were tested for moisture penetration by spraying water on one face and maintaining an air-pressure difference across the panel to simulate wind and rain. The resistance of the panels to moisture penetration varied greatly and depended on the properties of the brick and mortar in combination. Leakage occurred at the brick-mortar interface, and in some cases through the bricks. Information on the influence of air pressure on leakage and on the influence of wall thickness on leakage was obtained. Working properties of the materials affected the bricklayer's technique of constructing the panels. The effect on moisture penetration of weathering panels by outdoor exposure was also studied.

Air-pressure Chamber Soft Plostic

\

Sealing Strip

I

Sponge Plastic

-

Fig. 1.-Diagram of apparatus.

T. RITCHIE is an Associate Research Officer of the Division of Building Research of the National Research Council of Canada. H e graduated in ceramic engineering from the University of Toronto in 1949 and joined the Division of Building Research in 1950, where he has undertaken studies of problems relating to unit masonry construction. He is a member of ASTM Committee C-15 on Manufactured Masonry Units.

W. G. PLEWES is an Associate Research Officer of the Division of Building Research of the National Research Council of Canada. H e received his B.Sc. in Civil Engineer- ing from the University of Manitoba in 1949 and M.Appl.Sc. from Queen's University in 1954. After 3 yr with Canadian National Railways in the design of bridges and buildings and 2 yr as lecturer in civil engineering at the Royal Military College, Kingston, he joined the Division of Building Research in 1954, and has been engaged in structural research, prin- cipally in the field of concrete.

October 1960 (TP 183) 39

Authorized Reprint from the Copyrighted ASTM BULLETIN No. 249, October, 19GO Published by the American Society for Testing Materials, Philadelphia 3, Pa.

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Panel Construction and Testing I'aiirls wcrc coi~htri~(.tcd by :L 11r1ck-

layer of 111:~113r Y C S L ~ S ' ( ~ ~ j ) ( ~ r i e n c c n-110 was

instructctl to work c:~rcfully l ~ i ~ t l t o fill all the joints coinplctcly. I-Iis observations on thc Lvorking propcrtics of tllc various nlatcrials arc cliscussctl l a t n .

Mortar joints on one sidc of the panel

mcrc c.oiicavc-toolctl. I11 some cases

this n n s clone shortly aftcr the bricks were laid, but in othcr cascs only aftcr soinc hours, tlcpc~iitling on tlic rate of stiffening of the niortar. T h c bricklayer \ V L ~ S allo~ved t o tool tlic joiilts ~ v h r n hc consitlcrccl i t shoultl l ~ c done. In panels t h a t wcrc 8 ailcl 12 in. thick, colninoil bonding patterns were used, each s i ~ t l l course. co~uposctl of Iicatler bricks.

Flashings n-crc installrtl

: ~ t

tlic base of thc pmicls t o tlivcrt the spmy ancl leakagc I\-nter a t carh sidc. T ~ v o nlntcrials mcrc usotl, I ~ o t l ~ s:rtisfactorily: a \\ire-~.ciliSorccd :i~1)I1alt-ilnprcgnntctl fabric :~nd a tliili-gag? c011pcr s l i ~ c t . I n soinc ptincls thc fl:isliings n.c,rc laid about 2 in. in t l ~ c mortar joint :IS the

panel \\-as bring constructed, b u t i t ~ v a ~ foiiiicl cnsicr 111 1:itcr ~):rneIs to rakr

our the fresh mortar jolnts to a depth

of about in. and insert tllr flashing

and fastcn

it

111 pl:~cc wit11 cnulking

inatcrial.

\Vhcn tlicl 1)ricbl:iyc.r colitplctcd :L

pancl, tlic cdgc,s 2nd toll surfaccs n7crc covered with a mortar pnrgct t o lcvcl

them. \\-hen tlic pancl appcarctl dry

oil thc surface, caulking inatrrial was applirtl to tlic front aiid back fnccs in a strip ncar tlir ctlgcs. In this way a 40-~n. n,idth of br1cknol.k was left uncoveretl ant1 csposocl to tllc water spray in tllc. tcst. T l ~ c j):~i~els n.crcX storetl undcr uncoiitrollctl ant1 v a r ~ a l ~ l c

temperature :~ncl I l u ~ n ~ d i t y coiitlit~ons

for bet~vccn 30 and 40 days until tcstcd. During tlic tcst, observations Ivrre rnadc 01 tllc t ~ i i i c takrn for tlampncss to appear on tllr hack of t h r ~ ~ a i i c l , tllc dcvc1ol)lncnt of dnlnp :mas, ant1 the ratc of lcakagc of inoisturc tlirougl~ tile pancl :it ccrt:lm tiincs :~ftcr t h r start of thc tcst. The rate of lcakagc

was usually ~nrasured a t 5 ant1 30 min,

ancl I , 2, 3, 6, 24, and 48 hr aftc~r tlic start of the tcst.

Influence of Brick and Mortar on Moisture Penetration

Encli of the tllrcc clay ant1 shale

bricks mas usecl with two inortars in

constructing 8-in. panels, and each combination was ~ n a d c in duplicate, resulting in 12 panels in all. T h e two concrete bricks were also used wit11 two mortars, but only a single pancl of each co~nbination was nlaclc and one of thcin was broken accidcntally and n o t tcstcc\.

Resistance of tile various panels to inoisture penetration varied markedly.

TABLE 11.-INFLUENCE OF T Y P E OF BRICK AND MOILTAR. ON MOISTURE I'ENETILATION OF &IN. PANELS.

Brick S u o t , i o ~ ~ , g per 1rli11 per 30 sq iu. Mortar I'ortlnncl Cernerl t : Lime: Sand, hy Volume ( 2 t o 4 A . . . S t o 8 j 5 t o ~ l 5 t o 8 5 t o 19 B . . .

1

:5 t o 19 _{20 to 24} C . . . . { 80 t o 89 _, DO t o 69 , , , , , ,

j

90 t o 99 12 to 65 12 to 65 E . . . . 83 t o 124 Mortnr lt:~te of Lenkngc, Ih of water per lnin

per 100 sq f t of pariel iMauiinum A t D hr

N o t rccorclecl.

111 a few c:~scs tlicrc was no 1cak:lgc of ~ v a t r r through tlic pnucl, in otliers only a slight ainount, while in some c:rses moistmc passed through tlie panels vrry frecly. R,atc's of leakage arc coiiiparetl ill Table 11. Duriiig the tcsts i t was founrl t11:it tllc r:l.tc chaiigcd,

rising to :L nia~i1iiu1i1 value ant1 then

tlccrc:ising; the p:.incls, thcrcforc, arc coinparrcl oil tlic basis of thc ~n:rximun~ l(::~k:ig(, r:rto recorded 6 Iir :i.ft~r t h e s t a r t of tlic tvst. J,c!:rk:tgc rntc is

cs~)rcsscd as pouiitls of watcr por miiiutc

]):issi~~g t11l.ougIi 100 S(I ft of ~ : I ~ c I .

No 1c:lkagc: ~v:itc:r c:iiilc~ off tlic 11:rcks of 11:~ncls ill n.liicli brick h was usccl ~vitli citl~cr 111ort:t.r. For two panrls of tliis brick, tlicrc n.ns no dainl)ncss visible on tlic back of tlic pancl aftcr 24 lir of tcst, :.inti tlic othcr two panc.1~ liad 011157 n ft.\~- sinall tl:~n~p spots in t h c inortar joints.

P:incls of 1)rick 13 and tlic 1 : 2 : 9

inortar :illo~vc~tl ;I. rclutivcly slight

:iniouiit of Icnkagc t o t;rl;c pl:icc, ~vhilc wit11 thc s:imc 1iiort:rr panels of ))rick

C

nrcrc coiisidor:ibly rvorsc. \lTitll tllc 1 :

i

: 32 ~nortm., howcvcr, 1)ric.k~ 13 antl

C both liad a. ~ i i i ~ c l i Iiighcr rate of

leakage than with the 1 : 2: 0 nlortar.

In the case of brick 13, tlic pairs of

paiicls for thc two mortars wcrc con- structctl of bricks of slightly tliffcrcnt suction values, \vhich may ]lave in-

creased t h e cffcct of tlic c:liange in mortar.

The rcprotluci1)ility of rcsults nras not i~npressive, particularly for panels of I~rick B ancl 1 :

_f

: 32 mortar. Variation

in rcsults within pairs of panels, Iiom-

ever, mas n o t sufficient to mask the grciit differcnecs in lcnkagc charnctcris- tics resulting fro111 tlle type of brick and mortar usctl. For clay a n d shale bricks i t al~pcarrtl tliat tile Icakngc ratc increasecl as tlic suction of the I~rick incrcasctl, antl except for panels of tlic low-suction brick, tlie lcakagc late was n ~ u c l i higher for t h e 1: $:32

mortar tli:rn for the 1 : 2: 0 mortar.

I t is \veil known that different limes

liave tliffercnt cffccts on mortar properties sucli as water retentivity ant1 ac- cordingly on the extent of bond. The s:rlne improvcincnt in rcsistaiicc to moisture penetration wit11 increased

lime content of mortar \\~hich nras noted

with the particular lime usctl, may not occur ~vitli other linlcs.

Thc higher-suction concrctc brick E

Ivitli 1 : 2 : 0 inortar producetl a pancl of slightly greater leakage r:~tc than tliat, of brick D mith the same mortar. 'l'lir panel of brick

D

wit11 the 1 :

$:

3 2 n ~ o r t a r , however, was lo\vcr in lcakagc rate tl1:111 tliat wit11 the 1 : 2: 9 mort;ir, ~vhich was tile revcrsc of tlic situation for clay bricks 13 and

C.

L : ~ t c r t>rst;s

-

4 8 12 16 2 0 24

Time After Start Of Test, hr

Fig. 3.-Change of leakage rate of 8-in. panels during test.

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of two 4-in.-thick pancls of concrete brick E mere illaclc with thc rcsult t h a t

the p:~ncl n ith 1 ::: 3; inortar hacl a

much lligllcr leakagc ratc than that with

the 1 : 2: 9 mortar. The iilflucncc of

mortar coinposition on the moisture pelletration characteristics of concrete brick masonrjr thercfore is not clear. Change of Leakage Rate During Test

Tllc ratc of lcakage changccl during the tcsts, rising to a inasin~urn value in the first few hours and decreasing as thc tcst continued. Esaillplcs of the cllangc for thrce pancls arc shown in Fig. 3.

White streaks and discoloration ap- pearcd on thc backs of some panels.

This material, if deposited in opcnings

in the panel, could presumably reduce leakagc. Analysis of a sample obtained froin the back of one panel indicated that it was inainly calcium carbonate. Influence of Panel Thickness

on Moisture Penetration

With both mortars and brick C, panels werc constructed in thicknesses of 4, 5 i J 8, and 12 in., the sccond thickness bcing that of the oversize brick. Results of thc tests of thesc panels are compared in Tablc 111, on the basis of the maximum rate of lcakage recorded during thc tcst. The timc taken for the first dampness to appear on the back of the pancl after the start of the test is also sho\\m.

7 7

l h c 4- and 54-in. panels of both mortars, and tllc 8-in. panel of thc high- cenlrllt mortar started to leak very quickly and in relatively large quantity. Ilomcvcr, as the panel thickness increased the lcakagc rate generally dccreasecl, so that thc time interval became longer before dampness ap- pearcd on tllc back. For the 12-in.

panel \\-ith 1 : 2: 9 mortar clainpncss

appearccl :~ftcr 23 ininof test, althoughno

no watcr came off thc back of the pancl for over 3 11r. In the casc of thc 12-in.

pancl of 1 : 1% : 3; mortar, clarnpness

appearctl on thc back aftcr 16 min, but no lcakage wntcr came off the back for 1 hr.

Influence of Air Pressure on Rate of Leakage

Although the lcakagc rate changed during test, after W hr thc change was usually vcry gradual. I n thc test, of two pancls, when the leakagc ratc was thus fairly constant, the air-pressurc difference mas reducccl in stages to determine the effect on the ratc of leakage. One of

the pancls was of brick

C,

5 ; in. thick.

Lcakage rates of this pancl undcr thc normal air-pressure cliffcrcnce of 24 in. of watcr (used in the tcsts) and under retluccd pressures are shown in Table IV.

The leakage ratc of a very permeable 4-in. pailel of brick C was ineasured

T A B L E 111.-INFLUENCE O F TI-IICKNESS OI? PANICLS O F B R I C I I C O N h I O I S T U I ~ E P E N E T R A T I O N .

--

. M : L ~ ~ I ~ I I I ~ I L c t ~ k l ~ g e It:~t,c, 'I'irt~e for Darngtlcss I'a~lol - 111 - per ~ n i n per 100 --scl f t T o f\l~pc:~r _._. 011 Back

Thiclcncss, in. Mortar Mortar h o r t a r Mortar 1 : 2 : 9 1:!:3: 1 : 2 : 9 1 : % : 3 % 4 . . . 4.61 10.64 30 scc 15 s ~ r

under the normal tcst conditions of 24 in. air-prcssurc differcncc ancl then undcr no air-presswe cliffcrencc, with the rcsult that thc ratc of leakagc dropped from 10.3 to 1.9 lb of watcr

per inin pcr 100 sq ft of pancl. In

both tests, thercfore, it is apparent that thc rate of leakage was influcnced greatly by the air-pressure difference across the panel.

Leakage a t Mortar Joints and Through Bricks

When moisture pcnetratioil took place it usually occurrcd first in the mortar joints, although for panels of brick C and concretc brick dampness frequently appeared on the surface of a brick while the illortar joints surrouncl- ing it appeared to be dry. Small bub- bles wcrc sonlctimcs see11 a t thc brick surface when nloisture came through it. I n most panels, moisture penetration through the joints showccl up first a t the header bricks. In sonlc very pcr- meablc pancls air leakage through the mortar joints, betwcen mortar and brick, could be detected by placing the hand ncar thc pancl surface.

To deterininc thr proportion of leakage attributable to the mortar joints, threc panels of brick C (54-in. thickness) wcrc constructccl, one of 1 : 2: 9 mortar, the second of 1 :

$

: 3;, mortar and the third with caulkcd mortar joints. In the last casc, on completion

of the pancl tllc joints were rakccl out

on each side to a depth of about

3

in.

and subsequently packed with a caulking material. The results of these tests are shown in Table V, on the basis of the maxiinum ratc of lcakage re- corclcd during the test.

For this brick it \\-as indicated that

the proportioil of nloisture which pcnctrated the pancl through the bricks theinsrlvrs was relatively small compared to t h a t which pcnctratccl a t the mortar joints.

Mortar Working Qualities

Commcnts by the bricklaycr and diffcrences in bricklaying methods indi- catcd that working characteristics dif- fered appreciably for various comhina- tions of materials. No attempt was made to mix mortars to a standard consistency or to have thcm used in that state. The bricklayer could tem- per the mortar with watcr to adjust the consistency as he wished. Records were made of mortar flow, as an incli-

T A B L E 1V.-INFLUENCF7 011' A I R - I'RESSURE DIFFERENCE. ACROSS

P A N E L ON RATE O F LEAIIAGI3. Air I'rcssu~e Leakage Rate, Diffcrencc, ln. l b per mi11 per

of matcr 100 sq f t

Maximum Leakage l t a t e Mortar Ib per mi11

per 100 sq f t 1 : 2 : 9 . . . 3.01 1:%:33/.t . . . 5.43 Rakcd and caulked. . . . 0.60

a Assuming 110 lcakage through caulked

joint.

T A B L E V1.-FLOW VALUES O F MOIt- T A R S USED W I T H VARIOUS BRICKS. Mortar Flow. Der cent ,

.

Briclc M o r t a r mortar 1 : 2 : 9 l:I/!:33/4 A (suction 2 t o 8 g ) . . . . 1 0 9 . 5 118 B (suction 15 t o 24 g). . . 114 120 C (suction 60 t o 99 g). . . 1 1 4 . 5 12(i D (suctio~l 12 to 65 g) . . . 114 120 E (suction 83 to 124 g ) . . . . 117 129 Average for all

bricks. . . 114 123

cation of consistcncy, a s the bricklaycr used it with the various bricks. Thc average flow vvalues of sevcral measure- lllcnts arc shown in Table VI and indicate that the consistcncy was adjusted according to the type of brick used. As thc suctioil of the brick

increased thc nlortar was nladc wetter

to produce a higher flow valuc.

Wit11 a given brick t h c flow of the high-cement mortar was consistcntly inuch grcatcr than t h a t of thc high- lillle nlortar. Thc bricklayer was vcrg critical of the former mortar, since it was vcrv difficult to trowcl and to set bricks in it. Hc stated that it ncecled

inorc lime to make i t suitable, and

although in this work he is willing to use it he pointed out that, if specified for an actual building, it \vould not be

acceptable to bricklaycrs, who would

adjust thc workability by adding more lime. The 1 :2:9 Inortar was m i ~ c h more plastic and workable, and hc mas satisfied with it. I t staycd workable for a long period, whereas the

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1 : i : 3 $ nort tar stiffcllctl on thc: 1)o:~rtl in a sllort ti111c L L I ~ C ~ r(:quir('(l fr(:(lll(wt

t c ~ ~ l l ) ( > r i ~ ~ g ivitli \ v : ~ t c ~ to ~ ~ i : ~ i i l t : t i ~ i its \vorkal)ility. I t \\;:Ls scllsitivo to tllc:

mount of \\;:~ter atltl(ytl, : ~ ~ i ( l :~ltl1olig11 it coultl 11c "\~orlic:d up" t o sonlo tlrgrcc: of plasticity it stiff'ciicd u1)on st:lntlilig, mitli scgrcgatioll of \\;:~tc:r. In short, thc iv:~tcr rctc~ltioll values of tlio lnortars :~ppcarctl to ~,eflcct thcir ivorking 1)rop- crtics.

Tllc l~ricklnycr 1)clicvcd tli:~t t l ~ c s : ~ ~ l t l \vas too CO:L~SC :uld ri~sillt~(I ill 1i:~rsIi

1110rt:~r, but it \vas ~vcll-gratlcd :~ c ~ o r d i l i g

to specification rcquircmcnts. A sam-

plc of :~~iotlicr loc::~I s:~iicl lie llatl frc-

qucntly usctl 11~:~s supplic:tl by him for

inspection. I t tlitl not mcc~t specification rccluircmcnts for gr:~cling, lio~vcvcr, as i t co~ltai~lc:d consiclcra1)ly too ~uuc:h fine nlaterial. hltliough t l ~ c bri~kl:~y(lr originnlly csprc~ssctl tllc opi~iioil t h a t tllc saucl usctl W:LS too coi~rse, 11e 1:ltcr

attril~utcd mortar li:~rsl~ncss t o i~lsuffi-

cicrlt limc. I t was not clcar thcrcforct, ~vhicll of tllc t\vo factors, in his opinion govcrrlcd tllc ivorking qualities of tllc 111ort:lr.

Tllc bricklayer also pointed out t l u t nlortc~r nlising on a n actual job is tllc work of t h e Ilclpcr :i.ntl t h a t tllcrc

is 110 corlsistcnt proportioning of 1na-

tcrials; thcxy arc misctl, :ltlcling linic as

nccdccl, to protlucc :L mort:~r tlmt slides

easily off tllc sllovc~l. l'hc. "feel" tlcciclcs its :~cccptal)ility.

Tllc bricklnycr s a ~ d his 11ornlal pro- ceclurc was t o Iny out a furro\vccl ~ n o r t n r bcd sonic\vhat clccpcr tllall the dcsil.cd joint thickness so t h a t ttic bricalts co~lld be sllo~rccl or tappctl clo\vn into i t t o tllc rcquirctl l(,.ircl. In tllc construction of tllr l,ancls, lie\\ cvcr, Ilc \r:ls instructctl t o use :L flat, not furro\vc:tl, 111ort:~r I~cd. T.TTith tllc Iiigh-suction bric:lrs and high- cc?mctnt mortar ho \\,as not able t o sllovc the bricks c:lsilg into pl:~cc; thus, the mortar bctl was 1:~icl out only slightly thickrr tll:~n tl~c: final siec t o f:~cilitatc s e t t i ~ ~ g .

TIM: lcngth of mortar hccl laitl out in advallcc of setting bricks was lcft t o the bricklayer's prefcrcllcct. With the high-suction briclc C Ilc usunlly laid out

nort tar

for only one hriclt a t a tinlc;

with I-)rick U and thc high-ccmcnt

mortar he :ig:~in usually laid o u t nlortar for one brick only; but ivith tlic 1 :2:9

nort tar

Ilc sprc:~rI enough for two or thrcc bricks. TVith tllc low-suction

brick A :~ncl both mort:~rs, he laid out

mortar for

t\\

o or tlircc brivks mld oftcil

for the full panc.1 ~vidth of fivc bricks. This hrick \vas slippery on the mort:lr bed and L1floatctl" out of position easily by tlie slloving of adjacent bricks. Brick C rcqiiircd a n cscessive a~noiint of tapping into position bccausc of t h r rapid consoliclation of tllc mortar hen

the brick c:~nlc into contact nith

~ t .

T h c nlcdimn-suction brick 13 appcarecl to be rasily pl:~cccl in either mortar.

It \\.as (:i~stol~la~.\- for t h ~ bri(:kl:~ycr to ta,p all t l ~ c ty11c.s of 111,icks \vith the t~,oivrl i \ ; l i ( ~ i ~ s(btti~~g t l ~ ( ~ n ~ i l l tlic ~ l l o r t : ~ r ,

but ~ilucli 1i101.(: t:~l)l)i~ig ::\.:is nsu:~Ily

rlc:c~lctl wlic~~i t l ~ o Iligll-cc:nlcnt 111ort:~r ivas usctl. T a p l ~ i n g somctilucs up- pc~u.ctl to ope11 vortic:al joints a snla11 : ~ n l o u l ~ t , bcc:rusc, of slight Ilorizontal

nlovcilic~lt of tllc: bricks, :~ntl solllc

:~l)pcarcd to " r ~ c l i " on tlic nlortar bed

\\-hen laid, cr(5:~tilig :L \vetlg::c-shapctl

voitl l)ct\vcc~i 1110rt:~r ant1 hrick a t tllc etlgc. 'l'his was p:~rti(:uI:~rIy i i o t i ~ c : ~ I ~ I c with tlic $-in. \vide brick.

Pull 1)ctl joints :~i1(1 full c x t ~ ~ . i o r

\-crtic:~l joi~its \\;('r(: usctl, ill tllc l : ~ t t ~ r casc I)y l l l ) ~ t t e r i l ~ g " tllr ('11(1 of tli(: \)rick

\\,it11 :i 1 : ~ r g ~ : L I I ~ O L I ~ ~ of inortar I)cfor(: it

\v:l,s l:~i(l. 111 tlic 8- : L ~ ( I 12-ill. iv~ills, :L

vcrtical "collar" joint s('1):~r:~totl the l a y c r s o f ),ricks, :1nd tllc hrictk1:~ycr a t t c ~ ~ n p t e d to fill this joint by lisluslii~~g" inortar i r ~ f r o ~ u nbovc, \vorking it clo\\:n by cuttillg i t vcrtic::llly ivitli t l ~ c tro\vcl. Two ~ ~ a l w l s brok(:n : ~ ( : c i d ~ ~ l t a l l y rc- vcalcd tllat these joints I ~ C ~ C a l ~ n o s t

:~l\v:~ys inc01111)I~t~ly fillrtl : ~ n d cont:~inccl largo voids. 'l'llc mc~tllotl ilttclnptcd for filling tlie~ll tllcrc%forc: \\-as not ctffcc- tivc.

Effect of Outdoor Exposure o n Moisture Penetration

Llftc,r tllc first leakage tcst, lllany of thc p:~nckls \vcrc storctl out-of-doors for 2 yr or 1110rc, tlicn retcstecl to clctcrminc

the cffcct of \I cathcring on tlicir iuoisture

pcnctration prop(,rtirs. 111 most cases

therc ~ v 3 s inlprovc111cnt ill rcsistancc t o

moisture pcnctr:ltion or 110 changc.

One panel w:ls sliglitly ~ n o r c pc~rmcablc as :L rcsult of cxposurc. I n all rases tllc

clia~lgc in moisture pcllc>tration proper- tlos was not apprc,ciablc.

P:~ncls of t110 low-suctiol~ brick A

which \vcrc higllly rcsist:~~it ill tlle original tvst ircrc the s:Lnlc on retesting. P:incls of bricks 13 2nd C, with both mortars, \vcrc less pernlc:ll)lc on the scco~ld tcst. S l ~ g h t l y grcntcr leakage occurrcd in one of tllc concrctc l ~ r i c k

S u m m a r y a n d Conclusions

Rrsistancc of brickwork panels t o moisturr 11cnctr:~tion varietl grcatly tlcprncling on tllc brick and mortar combin:rtion; tlic suction of clay ant1

sllale bricks and t l ~ c mort:~r composi-

tion wcrc iml~ortant factors, confirlning tllc results of stuclirs nladc clscnllcre. For panels of collcretc I~riclcs, ho\vever,

tllc influcnco of

nort tar

composition

mas not clcar.

The tcsts inc1ic:~ted t h a t nloisturc pcnctmtiol~ \\,as associ:rted with tllc

mortar-brick intcrf:~cc. ,2lthough noi is-

ture penetration through the bricks took place with solnc types of bricks,

thc n ~ a j o r :~ino[u~lt of Icalt:~gc> apl~carcd to br nt the interf:~cc. In ~ I ~ : L I ~ J of tli(b

S-in. pullc'ls tcstctl t l ~ c IIC:L~(Y (tol~rses co~~tributccl gl.(%:~tly to the ~ : l r l y 1~:~li- :Lge of t110 1)allrls.

Infor~llation \\:IS oI)tain(~cI lor o11(~

type of brick 011 tlic cffcct of \\.:LII

tllickllcss on ~iioisturc ~ ~ c ~ i c t r a t i o l ~ , : ~ n d oil tlic cff'cct of tlic :~ir-prc>ssuro diffcrencc :~cross a 1):111(>1 011 its lcnk:igc

ratc; I~otll of tllcsc factors liad nu npprccinblc iilflucilcc on 1r:ikngc.

Ol~scrvations II~:L(IC tluring panel con-

struction sllo\\;ctl that tlic bric,kl:~yer's tccliniquo v:Lrictl to :uljust t o clia~igcs in tllc prol)ctrtics of tlic ~iiatcri:ils, rcsultillg in sul~stnlitial tliffcrc~l~ccs ill

n1ort:~r flow, tapping of I~ricks, anti mor-

t a r l l ~ ~ ~ r ~ a ( l outf1 for tli(' v:~rioi~s ty11cs of bricks ancl inortars usctl.

Outtloor csposurc of p:~nt.ls for two or 111orc \vintcrs dicl not linvc: any :~p- prcc:iable cffcct on moisture polletration for tlic matcri:~ls used. Alorc cstonsivc stutlics m:~tlc clsc\\;hcrc ( 6 ) of tllc cffcct of \\;cathering on inoisture l)cnrtr:~tion of solid brick walls 11:ivc gi.irc.11 simi1:ir rcsults.

-Tlic stutlics rcl~ortcd in this pilpcr arc of a 1)rcliulinnry 11aturc ant1 tlic scope of tllc invcstig:ltiolls only broad enough t o intlicatc tllc iinl~ortnlico of solllc f:~etors iliflu~~icillg ~noistllrc IICIIC-

tration of brick nlasonry. Ful.thcr studics arc being nladc ill tho Division of 13uilcling Rcscarch on solnc of thcsc factors.

R E P E R E N C ~ ; ~

(1) T. Ititchic, and \\'. G. Plcwes, "A Itcview of Literature on 1t:~iii Perle- trntioii of Uuit hlaso~iry," P?iblicct!ior~ Aro. 4336, National Itcsearch Couilcil of Canatla, Divisior~ of Ruilcling Itesearrh, ljlay, 1957.

( 2 ) C. C. Ipishburr~, D. nTntstoil~, : L I ~ I). E. Parsons, "\irater Permeabilily of I\lasonry Walls," Uuiltlil~g h,Iatcrinls

and Struc~tures Repor1 BildS 7, N:L~..

Burcnri S t ~ ~ ~ l d a r d s , Oc:td. 8, I!):%.

(3) C. C. Fishburn, "\Yntcr 1'errncal)ility of \\7alls Built of i\lasonry Units,"

Building Materials and Structures

Reporl B J l S 52, Nnt,. 13ure:~n Staritl- ards, April 15, 1942.

(4) National Building Coclc of Ci~ilada,

1953. Issued by thc Associate Ck1111- inittce on thc N:~t,ion:~l Bl~ilcling CJodc,

National 1to~c:~rcIl Conncil, 1'1iblicc~-

lion Aro. 3158.

(5) It. L. A. S(:hoonlnltcr :111cl I. \\louters, "Wind 1,oads or1 Buildiiigs," ?'echn.icol Translation. T T 485, Watioriul Re- search Council of Canada, (from IlcL

Bouwhedrijf, Val. 9, No. 22 (1932)).

( 6 ) C. C. Fishburn, D. E. I'arsons, arld P. IS. Peterson, "Effect of Outcloor E x p o s ~ ~ r c on the \\'atel Pel.meahility of klnsonry Walls," BuiIding &Into-

rials and Structures Keport B11lS 76,

Nat. Brireau Star~dartls, Ang. 15,

1941.