Astm stp 1180 1993

Foreword This publication, Masonry: Design and Construction, Problems and Repair, contains papers presented at the symposium of the same name held in Miami, FL on 8 Dec.. Copyright b

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STP 1180

Masonry: Design and

Construction, Problems and Repair

John M Melander and Lynn R Lauersdorf, editors

ASTM Publication Code Number (PCN)

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Library of Congress C a t a l o g i n g - i n - P u b l i c a t i o n Data

Masonry : design and construction, problems and repair / John M

Melander and Lynn R, Lauersdorf, editors

(STP ; 1180)

Includes bibliographical references and index

ISBN 0-8031-1492-3

1 Masonry Congresses I Melander, John M., 1949-

II Lauersdorf, Lynn R., 1937- Ill Series: ASTM special

is 0-8031-1492-3/93 $2.50 + 50

Peer Review Policy

Each paper published in this volume was evaluated by three peer reviewers The authors addressed all of the reviewers' comments to the satisfaction of both the technical editor(s) and the ASTM Committee on Publications

The quality of the papers in this publication reflects not only the obvious efforts of the authors and the technical editor(s), but also the work of these peer reviewers The ASTM Committee on Publications acknowledges with appreciation their dedication and contribution

to time and effort on behalf of ASTM

To make technical information available as quickly as possible, the peer-reviewed papers

in this publication were printed "camera-ready" as submitted by the authors

Printed in Fredricksburg, VA

May 1993

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Foreword

This publication, Masonry: Design and Construction, Problems and Repair, contains pa-

pers presented at the symposium of the same name held in Miami, FL on 8 Dec 1992 The

symposium was sponsored by ASTM Committees C-1 on Cement, C-7 on Lime, C-12 on

Mortars for Unit Masonry, and C-15 on Manufactured Masonry Units Lynn R Lauersdorf,

State of Wisconsin, and John M Melander, Portland Cement Association, presided as

symposium co-chairmen, and were editors of this publication

Downloaded/printed by

University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized

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Contents

O v e r v i e w - - L R LAUERSDORF AND J M MELANDER ix

DESIGN AND DETAIL Design a n d Testing to R e d u c e Efflorescence P o t e n t i a l in New B r i c k M a s o n r y

B r i c k V e n e e r W a l l s - - P r o p o s e d Details to A d d r e s s C o m m o n A i r a n d W a t e r

P e n e t r a t i o n P r o b l e m s - - R s PIPER AND R J KENNEY 22

The Influence of Horizontal Reinforcement on the Shear Performance of Concrete

M a s o n r y W a i l s - - s FOLTZ AND C W C YANCEY 32

E c o n o m i c a l Design of Shelf A n g l e s - - R H R TIDE AND N V KROGSTAD 60

I n t e r i m R e p o r t o n a S t u d y to D e t e r m i n e L a p Splice R e q u i r e m e n t s for R e i n f o r c e d

M a s o n r y - - M P SCHULLER, M I HAMMONS, AND R H ATKINSON 75

Seismic B e h a v i o r of U n r e i n f o r c e d Hollow Clay Tile Infilled F r a m e s - -

R D FLANAGAN, R M BENNETT, AND J E BEAVERS 91

INSTALLATION AND MATERIALS

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Frictional Characteristics of Clay Brick P a v e r s - - B E TRIMBLE AND

Laboratory Study of the Corrosion of Steel Studs and Screws used in Masonry

Influence of Aggregate Microstructure on the Volume Stability of Lightweight

Concrete M a s o n r y - - T w BREMNER AND D RAE 186

Variables Affecting the Strength of Masonry M o r t a r s - - a T WRIGHT,

TESTING AND EVALUATION Flexural Bond Strength T e s t i n g m A n Evaluation of the Bond Wrench Testing

A Comparative Review of Various Test Methods for Evaluating the Water

Penetration Resistance of Concrete Masonry Wall U n i t s - - M E DRISCOLL

Comparison of Laboratory Freeze-Thaw Procedures M A VICKERS 240

Predicting Durability of Brick Veneer Walls in Cold Ciimates J E LOVATT 250

Using Modified ASTM E 1105 to Evaluate the Resistance of Masonry Barrier,

Mass, and Skin Walls to R a i n - - N v KROGSTAD AND R A WEBER 265

Evaluation of ASTM E 514-90 Water Penetration and Leakage Test to Assess

Performance of Integral Water Repellent A d m i x t u r e s - - D CHIN AND

A Theoretical Model of Water Penetration Into Concrete Masonry U n i t s - -

Including ASTM E 514 Tests in Field Evaluations of Brick M a s o n r y - -

K R HOIGARD, R J KUDDER, AND K M LIES 314

Procedures and Fixtures for Removing, Capping, Handling, and Testing Masonry

Prisms and Flexural Bond S p e c i m e n s - - w D JONES ANt) M B BUTALA 326

STRATEGIES AND TECHNIQUES Quantification of Masonry Deterioration through Statistical M o d e l l i n g - -

A Case S t u d y - - A R WHITLOCK, w B FAIRLEY, AND A J IZENMAN 341

Evaluation of Injectable Cementitious Grouts for Repair and Retrofit of M a s o n r y - -

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Cladding an Existing Building with Masonry Veneer G o COLE AND

Deterioration and Stabilization of Berea Sandstone on the Hamilton County

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Overview

These proceedings are the seventh in a series of ASTM symposia on masonry that began

in 1974 Committee C-1 on Cement formally joined with Committees C-7 on Lime, C-12

on Mortars for Unit Masonry, and C-15 on Manufactured Masonry Units in sponsoring this

symposium Eighteen papers were presented orally at the symposium and the other ten were

presented in poster sessions The symposium continued to provide a forum for the dissem-

ination and exchange of information and experiences related to all facets of masonry

Special Technical Publications (STP) containing papers presented at five of the six pre-

ceeding masonry symposia were also published by ASTM The list of these symposia follows

9 STP 589 Masonry: Past and Present, from the symposium held June 25, 1974, in

Washington, D.C., was the first in this series It provided a basis for future symposia

The second symposium in this series was held June 29, 1976, in Chicago, IL Twelve

papers were presented, but an STP was not published from this symposium Several of the

papers appeared in ASTM's Journal of Testing and Evaluation

9 STP 778 Masonry: Materials, Properties, and Performance, from the symposium held

Dec 9, 1980, in Orlando, FL, covered the third in the series

9 STP 871 Masonry: Research, Application, and Problems, from the symposium held

Dec 6, 1983, in Bal Harbour, FL, covered the fourth in the series It was dedicated

to J Ivan Davison

9 STP 992 Masonry: Materials, Design, Construction, and Maintenance, from the sym-

posium held Dec 2, 1986, in New Orleans, LA, covered the fifth publication in the

series

9 STP 1063 Masonry: Components to Assemblages, from the symposium held Dec 5,

1989, in Orlando, FL, covered the sixth in the series It was dedicated to Alan H

Yorkdale

9 STP 1180 Masonry: Design and Construction, Problems and Repair, from the sym-

posium held Dec 1992, in Miami, FL, covered the seventh and latest in the series that

continues

Russell H Brown, Clemson University, John T Conway, Holnam, Inc., Kenneth A

Gutschick, National Lime Association, Harry Harris, Ash Grove Cement Co., George Judd,

consultant, and John H Matthys, University of Texas at Arlington, served as the symposium

steering committee Russell H Brown, George Judd, Harry A Harris, and John H Matthys

each chaired the respective oral presentation sessions titled: Design and Detail, Installation

and Materials, Testing and Evaluation, and Strategies and Techniques The 28 papers pre-

sented at the symposium and published in this STP were peer-reviewed by 90 ASTM com-

mittee members from C-l, C-7, C-12, and C-15

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Numerous A S T M staff members provided needed guidance Thanks are extended to these

as well as the authors and all others who made the symposium and proceeding publication

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D E S I G N A N D T E S T I N G T O R E D U C E E F F L O R E S C E N C E

P O T E N T I A L I N N E W B R I C K M A S O N R Y W A L L S

Construction, Problems and Reoair, A S T M STP 1180, J M M e l a n d e r and L R

Philadelphia, 1993

m a s o n r y either onto the surface or into the pores of b r i c k m a s o n r y walls

T h e s e deposits m a y be the substances themselves or secondary reaction products of t h e m with the atmosphere Investigations of e f f l o r e s c e n c e on

b r i c k m a s o n r y w a l l s on dozens of structures t h r o u g h o u t the U n i t e d States

by the authors and their colleagues have revealed that the e f f l o r e s c e n c e

on a p p r o x i m a t e l y 50 percent of the 43 samples s t u d i e d c o n s i s t s of w a t e r soluble sulfate compounds and that the e f f l o r e s c e n c e on a p p r o x i m a t e l y 40

p e r c e n t of the samples studied consist of c a l c i u m carbonate (carbonated

compounds are p r e d o m i n a n t in efflorescence on b r i c k masonry, the source of the e f f l o r e s c e n c e is usually the brick C a l c i u m carbonate "efflorescence"

soluble e f f l o r e s c e n c e on b r i c k m a s o n r y is m o s t likely a sulfate compound

w h i c h o r i g i n a t e d from the brick

To reduce the potential for e f f l o r e s c e n c e d e v e l o p m e n t in b r i c k

m a s o n r y walls, the bricks m a n u f a c t u r e d for a specific building should be

t e s t e d in accordance w i t h A S T M C 67, M e t h o d of Sampling and T e s t i n g B r i c k and S t r u c t u r a l Clay Tile In addition, they should be c h e m i c a l l y analyzed for w a t e r - s o l u b l e constituents to assess the e f f l o r e s c e n c e potential of the brick

The potential for efflorescence development in b r i c k m a s o n r y walls can also be reduced through the use of drainage type walls with a proper flashing and w e e p system and through the use of good c o n s t r u c t i o n practices and proper material selection

sills, sulfates, w a t e r penetration, w a t e r - s o l u b l e salts

E f f l o r e s c e n c e has been defined as a deposit of w a t e r - s o l u b l e salts either on the surface or w i t h i n the pores of b r i c k m a s o n r y walls [!] In the vast m a j o r i t y of cases w h e r e efflorescence has occurred, it has been

w h i t e in color, as shown in Fig I In a few cases, certain v a n a d i u m and

*Principal and Chicago Unit Manager, Wiss, Janney, E l s t n e r Associates, Inc (WJE), Chicago, IL

2Consultant, E r l i n Hime Associates (EHA) D i v i s i o n of WJE, Northbrook,

IL

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4 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

m o l y b d e n u m components p r e s e n t in some b r i c k units can p r o d u c e n o t i c e a b l e

green e f f l o r e s c e n c e on the surface of w h i t e b r i c k m a s o n r y walls

The "brown stains" on b r i c k masonry walls resulting from the presence

of either iron or m a n g a n e s e compounds in the brick units are t e c h n i c a l l y

not e f f l o r e s c e n c e because these compounds are not w a t e r - s o l u b l e and

e f f l o r e s c e n c e by definition is a deposit of w a t e r - s o l u b l e salts

Fig I - V i e w of efflorescence on b r i c k m a s o n r y wall

The presence of efflorescence on the surface of b r i c k m a s o n r y walls

is n o r m a l l y unsightly and, therefore, adversely affects the aesthetics of

w a l l s normally does not, per se, affect the strength or d u r a b i l i t y of the

wall w i t h i n pores in the bricks, forces p r o d u c e d from c o n f i n e m e n t of

c o n t i n u i n g e f f l o r e s c e n c e deposits in the pores can lead to cracking and

spalling of bricks w h i c h adversely affect the strength and durability, as

w e l l as the appearance of the wall

C o n f i n e m e n t of continuing efflorescence deposits by the glaze on

g l a z e d b r i c k units in brick m a s o n r y walls or by "water proofing" and

"water repellent" coatings applied on the surface of b r i c k m a s o n r y walls,

can p r o d u c e forces that can cause spalling of bricks, as shown in Figs 2

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CHIN AND PETRY ON REDUCING EFFLORESCENCE POTENTIAL 5

resulting from freezing of water trapped inside the brick by the water- impermeable glaze or coating

build-up behind glaze

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Fig 3 - S p a l l i n g of bricks due to e f f l o r e s c e n c e b u i l d - u p

b e h i n d "water repellant" c o a t i n g

In order for e f f l o r e s c e n c e to occur on b r i c k m a s o n r y walls, the Brick

c o n d i t i o n s m u s t s i m u l t a n e o u s l y exist in the wall:

I W a t e r - s o l u b l e salts must be p r e s e n t w i t h i n or in c o n t a c t with

the b r i c k m a s o n r y wall,

2 W a t e r m u s t be able to gain access into the w a l l in sufficient

amounts and come in contact w i t h the w a t e r - s o l u b l e salts for a sufficient

time to p e r m i t the salts to dissolve

3 The w a l l e n v i r o n m e n t m u s t be conducive to e v a p o r a t i o n of w a t e r

that p e n e t r a t e s into the wall

B a s e d u p o n the above conditions, the potential for the d e v e l o p m e n t

of e f f l o r e s c e n c e on b r i c k m a s o n r y walls can be e l i m i n a t e d if none of the

m a t e r i a l s u s e d to c o n s t r u c t the b r i c k w o r k c o n t a i n s w a t e r - s o l u b l e

substances, or if no w a t e r is p e r m i t t e d to p e n e t r a t e into the w a l l after

it is constructed These conditions are not p o s s i b l e in b r i c k m a s o n r y

walls e x p o s e d to the w e a t h e r because w a t e r - s o l u b l e substances cannot be

p r a c t i c a l l y e l i m i n a t e d t o t a l l y from all m a t e r i a l s used in m a s o n r y

c o n s t r u c t i o n and b e c a u s e b r i c k m a s o n r y w a l l s are not i m p e r m e a b l e to water

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Therefore, from a practical standpoint, the potential for efflorescence

potential for efflorescence development on brick masonry walls on a

building can be reduced by the following:

specific building to determine the potential of the brick to cause

efflorescence

masonry walls,

water penetration into brick masonry walls

T E S T I N G

The authors and their colleagues have performed dozens of investigations

of efflorescence on brick masonry walls The investigations have included

the following:

in the efflorescence using x-ray diffractometry, chemical analysis, and

petrography

diffractometry, chemical testing, petrography, and ASTM C 67 efflorescence

testing of unused brick samples, if available, to determine the source of

the compound(s) that caused the efflorescence

path(s) of water entry into brickwork

A N A L Y S I S O F E F F L O R E S C E N C E S P E C I M E N S

The principal efflorescence compounds found on brickwork in 43 different

samples from 24 separate projects investigated by the authors and their

colleagues throughout the united Stated are as follows, in order of

frequency of o c c u r r e n c e :

The most common efflorescence compounds found by other researchers

are:

alkali-earth (calcium, magnesium and aluminum) sulfates and, to a lesser

degree, carbonates" [3]

sodium and potassium appear" [4]

The efflorescence compounds found on the brickwork of the 43 samples

p o t a s s i u m carbonate, sodium carbonate and aluminum sulfate which were

found by other researchers were not found on the effloresced buildings

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researchers

E f f l o r e s c e n c e C o n s i s t i n q of C a l c i u m Carbonate

C a l c i u m carbonate was found to occur by itself in the "efflorescence"

on 15 (approximately 35 percent) of the e f f l o r e s o e n t samples i n v e s t i g a t e d

and in c o m b i n a t i o n with other efflorescence components in two of the other

"efflorescence" in 17 (approximately 40 percent) of the 43 samples

T A B L E 1 - - E f f l o r e s c e n c e Compounds Identified on B r i c k w o r k in 43 Samples

Calci1"m carbonate is technically not e f f l o r e s c e n c e (by the previous

definition) because it is not w a t e r soluble and did not originate as a

salt in the masonry, when the "efflorescence" on b r i c k w o r k consists

p r i m a r i l y of c a l c i u m carbonate, the source of the e f f l o r e s c e n c e is usually

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the mortar The formation m e c h a n i s m of c a l c i u m c a r b o n a t e "efflorescence"

h y d r o x i d e is dissolved b y t h e water, and as the w a t e r evaporates it brings

carbon dioxide in the air at the face of the brickwork, the c a l c i u m

hydroxide carbonates to form c a l c i u m carbonate w h i c h is not w a t e r soluble

and will not be w a s h e d off the b r i c k w o r k by rain

Because c a l c i u m carbonate "efflorescence" originates from p o r t l a n d

cement, m a s o n r y cement, and lime, every b r i c k m a s o n r y w a l l has the

potential of forming c a l c i u m carbonate "efflorescence" w h e n significant

amounts of w a t e r are able to penetrate the brickwork C a l c i u m carbonate

"efflorescence", therefore, cannot be c o n t r o l l e d by p r e c o n s t r u c t i o n

d e v e l o p m e n t of c a l c i u m carbonate "efflorescence" can be m i n i m i z e d and

perhaps e l i m i n a t e d w i t h the use of proper design details and good

c o n s t r u c t i o n practices that result in a wall that does not permit

significant amounts of w a t e r to penetrate it

O t h e r researchers have suggested that in order to m i n i m i z e the

d e v e l o p m e n t of alkali (sodium and potassium) b a s e d efflorescence, the

"free alkali" solutions of sodium and p o t a s s i u m hydroxide in cements used

hydroxides undergo carbonation and form "new b u i l d i n g bloom." However,

since t h e s e compounds are w a t e r soluble and of limited q u a n t i t y (typically

less t h a n half a p e r c e n t in p o r t l a n d cement), they are soon w a s h e d away by

carbonates rarely c h r o n i c a l l y remain as e f f l o r e s c e n c e on b r i c k masonry

E f f l o r e s c e n c e C o n s i s t i n q of Sulfate Compounds

A c o m b i n a t i o n of sulfate compounds was found in e f f l o r e s c e n c e on 20

sulfate t e t r a h y d r a t e was found by itself in the e f f l o r e s c e n c e on one of

the samples and sodium sulfate was found by itself in the e f f l o r e s c e n c e on

compounds were, therefore, found in the e f f l o r e s c e n c e on 22 (approximately

50 percent) of the 43 samples investigated

W h e n e v e r sulfate compounds are p r e d o m i n a n t in e f f l o r e s c e n c e on b r i c k

p r e d o m i n a n c e of c a l c i u m sulfate in e f f l o r e s c e n c e indicates that the clay

d e v e l o p m e n t will be found in the firing process" [8]

The sulfate compound in cements used to make mortars is i n t r o d u c e d

into cement during m a n u f a c t u r e as gypsum w h i c h is i n t e r g r o u n d with the

p r o d u c e d by the action of c a l c i u m sulfate on c a l c i u m aluminate to produce

t r i s u l f o a l u m i n a t e (ettringite) and monosulfoaluminate, both of w h i c h are

only slightly soluble in aqueous solutions resulting from rainwater that

do not cause significant efflorescence

Sulfate e f f l o r e s c e n c e compounds are w a t e r soluble, and e x c e p t for

c a l c i u m sulfate, w h i c h has limited solubility, they are n o r m a l l y w a s h e d

off the w a l l by rain water Since the most common m o r t a r - o r i g i n a t e d

efflorescence, c a l c i u m carbonate, is not w a t e r soluble, the p r e s e n c e of a

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e f f l o r e s c e n c e is most likely a sulfate c o m p o u n d and o r i g i n a t e d from the

brick

To reduce the potential of b r i c k - o r i g i n a t e d e f f l o r e s c e n c e "changes

additives to the raw materials, higher firing temperatures, m o r e u n i f o r m

f i r i n g distribution, different firing schedule, alterations to the flow of

w a s t e - h e a t gases, or changes to the firing atmosphere" [ ~ ]

T o r e d u c e the potential of b r i c k - o r i g i n a t e d e f f l o r e s c e n c e in

c o m p l e t e d b r i c k m a s o n r y walls, the following p r e c o n s t r u c t i o n testing of

b r i c k s s p e c i f i c a l l y m a n u f a c t u r e d for a p a r t i c u l a r b u i l d i n g should be

p e r f o r m e d in the laboratory to assess the e f f l o r e s c e n c e potential of the

b r i c k and to aid in the final approval and acceptance of the brick:

i W a t e r e x t r a c t i o n of p u l v e r i z e d b r i c k specimens for

i d e n t i f i c a t i o n of w a t e r soluble compounds, and analyses of t h e m for

sulfate, alkalies, magnesium, and calcium

Additionally, w h e r e possible the p e r f o r m a n c e history of the bricks

in similar environments should be obtained

E f f l o r e s c e n c e C o n s i s t i n q of Chlorides

The e f f l o r e s c e n c e on three (approximately 7 percent) of the 43

samples i n v e s t i g a t e d was found to consist primarily of a c o m b i n a t i o n of

p o t a s s i u m chloride and s o d i u m chloride P o t a s s i u m and s o d i u m chloride

e f f l o r e s c e n c e has several sources:

I Muriatic acid (hydrochloric acid) used to c l e a n the b r i c k w o r k

2 A c c e l e r a n t ("anti-freeze" compounds) in m o r t a r

3 Sea w a t e r either in the m o r t a r (usually from sand w a s h e d in sea

water) or d e p o s i t e d on the building in an ocean-side environment

To reduce the potential of c h l o r i d e - b a s e d e f f l o r e s c e n c e compounds,

the use of muriatic acid types of cleaning agents and c h l o r i d e - b a s e d

m o r t a r additives should be avoided

E f f l o r e s c e n c e C o n s i s t i n q of Glycolate

The e f f l o r e s c e n c e in one (approximately 3 percent) of the 43 samples

i n v e s t i g a t e d was found to contain c a l c i u m glycolate compounds w h i c h

p r o b a b l y o r i g i n a t e d from an anti-freeze (ethylene glycol) additive used in

the m o r t a r during cold w e a t h e r placement

DESIGN AND CONSTRUCTION

The sources of w a t e r that penetrate b r i c k m a s o n r y walls include rain

water, g r o u n d water, and c o n d e n s a t i o n from the interior of the building

Of t h e s e three sources, rain w a t e r is the primary source of w a t e r for the

f o r m a t i o n of e f f l o r e s c e n c e in b r i c k m a s o n r y walls

W a t e r p e n e t r a t i o n tests p e r f o r m e d on uncracked b r i c k m a s o n r y walls

d u r i n g investigations of e f f l o r e s c e n c e and of w a t e r leakage conditions by

the authors and their colleagues have revealed that the vast m a j o r i t y of

the rain w a t e r that penetrates the brick m a s o n r y w a l l s tested enters

t h r o u g h the m o r t a r joints, primarily at the interface between the m o r t a r

a n d b r i c k units

R e d u c t i o n in the amount of rain w a t e r that is able to penetrate into

a b r i c k wall will reduce the potential for e f f l o r e s c e n c e development The

following conditions will significantly improve the w a t e r tightness of

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2 G o o d bond between m o r t a r and brick

4 Joints that are c o m p l e t e l y filled with mortar

5 P r o p e r l y t o o l e d concave and v-groove m o r t a r joints

6 M o r t a r that did not freeze during cold w e a t h e r construction

A l l of these 6 items can be achieved in b r i c k walls w i t h good

specifications and normal, p r o p e r w o r k m a n s h i p practices

Tests p e r f o r m e d by Brown [10] revealed that, under the conditions of

his tests, "walls c o n s t r u c t e d with p o r t l a n d c e m e n t / l i m e mortars are more

resistant to w a t e r permeance than those c o n s t r u c t e d w i t h m a s o n r y cement

mortars." Tests p e r f o r m e d by Matthys [11] r e v e a l e d that u n d e r the

conditions of his tests, "the m a s o n r y c e m e n t / m o r t a r walls leaked

s i g n i f i c a n t l y m o r e than the p o r t l a n d c e m e n t ~ l i m e m o r t a r walls" Our

and [14] have indicated that under the conditions of their tests, there

was no s i g n i f i c a n t d i f f e r e n c e in w a t e r p e n e t r a t i o n r e s i s t a n c e of m a s o n r y

assemblies c o n s t r u c t e d w i t h p o r t l a n d c a m e n t / l i m e m o r t a r s and those

c o n s t r u c t e d w i t h m a s o n r y c e m e n t mortar T h e m o r e w a t e r t i g h t a wall is the

less potential it has to effloresce

To reduce the potential for e f f l o r e s c e n c e from w a t e r that does

p e n e t r a t e b r i c k walls, the w a t e r should be c o l l e c t e d and d r a i n e d out of

the wall as q u i c k l y as possible This condition is best achieved with the

use of drainage type walls with a p r o p e r flashing and w e e p h o l e system

located at all of the following strategic locations:

w a t e r from c o n t a c t i n g the brickwork

4 B e l o w w i n d o w sills

5 B e l o w copings

To be most effective, the front edge of the flashing should be

e x t e n d e d b e y o n d the exterior face of the b r i c k w o r k and be t u r n e d downward

to form a drip, and the joint directly b e l o w the flashing should be sealed

w i t h sealant In addition, end dams should be d e s i g n e d and installed at

the d i s c o n t i n u o u s ends of the flashing to p r e v e n t w a t e r c o l l e c t e d b y t h e

is u s u a l l y not effective in c o l l e c t i n g and diverting w a t e r out of the wall

w h e n its front edge is recessed in from the front face of the b r i c k w o r k or

w h e n end dams are not installed

The use of drainage type walls and the use of flashing b e l o w copings

and sills and at the base of the walls further reduces the potential for

d e v e l o p m e n t of efflorescence, because the exterior b r i c k w o r k w y t h e in the

wall is separated from dissimilar materials such as concrete block,

r e i n f o r c e d concrete, and stone that m a y contain soluble salts that could

c o n t r i b u t e to e f f l o r e s c e n c e on the brickwork

D e s i g n elements that enhance the potential for d e v e l o p m e n t of

e f f l o r e s c e n c e and that should be avoided include:

B r i c k w o r k sills, as typically shown in Fig 4

B r i c k w o r k copings, as typically shown in Fig 5

B r i c k w o r k pavements with m o r t a r joints, as t y p i c a l l y shown in

B r i c k w o r k planter boxes, as typically shown in Fig 7

These b r i c k w o r k design elements, e s p e c i a l l y sills, copings, and

pavements, e n h a n c e the potential for d e v e l o p m e n t of e f f l o r e s c e n c e b e c a u s e

they are m o r e susceptible to rain w a t e r p e n e t r a t i o n due to t h e i r m o r t a r

joints b e i n g h o r i z o n t a l l y exposed

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F i g 4 - V i e w o f e f f l o r e s c e n c e b e l o w b r i c k w o r k s i l l

C o p y r i g h t b y A S T M I n t ' l ( a l l r i g h t s r e s e r v e d ) ; S u n D e c 2 7 1 4 : 4 1 : 4 0 E S T 2 0 1 5

D o w n l o a d e d / p r i n t e d b y

U n i v e r s i t y o f W a s h i n g t o n ( U n i v e r s i t y o f W a s h i n g t o n ) p u r s u a n t t o L i c e n s e A g r e e m e n t N o f u r t h e r r e p r o d u c t i o n s a u t h o r i z e d

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F i g 5 - V i e w o f e f f l o r e s c e n c e b e l o w b r i c k w o r k c o p i n g

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F i g 6 - V i e w o f e f f l o r e s c e n c e o n b r i c k w o r k p a v e m e n t

C o p y r i g h t b y A S T M I n t ' l ( a l l r i g h t s r e s e r v e d ) ; S u n D e c 2 7 1 4 : 4 1 : 4 0 E S T 2 0 1 5

D o w n l o a d e d / p r i n t e d b y

U n i v e r s i t y o f W a s h i n g t o n ( U n i v e r s i t y o f W a s h i n g t o n ) p u r s u a n t t o L i c e n s e A g r e e m e n t N o f u r t h e r r e p r o d u c t i o n s a u t h o r i z e d

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3 W h e n e v e r the "efflorescence" on b r i c k w o r k consists p r i m a r i l y of

c a l c i u m carbonate, the source of the e f f l o r e s c e n c e is u s u a l l y the p o r t l a n d

cement, m a s o n r y cement, and/or the lime u s e d to m a k e the mortar

4 T h e p o t a s s i u m and sodium c h l o r i d e e f f l o r e s c e n c e found m a y have

o r i g i n a t e d f r o m m u r i a t i c acid (hydrochloric acid} u s e d to clean the

brickwork, c h l o r i d e - b a s e d additives, or sea w a t e r in t h e m o r t a r or

d e p o s i t e d on t h e b u i l d i n g in an o c e a n - s i d e environment

5 T h e g l y c o l a t e c o m p o u n d e f f l o r e s c e n c e found w a s c a u s e d by an

a n t i - f r e e z e additive that was added to the mortar

6 The sulfate e f f l o r e s c e n c e compounds t h a t w e r e f o u n d in

a p p r o x i m a t e l y 50 p e r c e n t of the samples i n v e s t i g a t e d are w a t e r soluble and

a c c o r d i n g to other researchers, the source of sulfate e f f l o r e s c e n c e

compounds on b r i c k m a s o n r y is u s u a l l y the brick The c a l c i u m carbonate

"efflorescence" c o m p o u n d that was found in a p p r o x i m a t e l y 40 p e r c e n t of the

samples i n v e s t i g a t e d is not w a t e r soluble and o r i g i n a t e d from the m o r t a r

u s e d to c o n s t r u c t the b r i c k w o r k walls These data s t r o n g l y suggest that

w a t e r soluble e f f l o r e s c e n c e on b r i c k m a s o n r y is m o s t likely a sulfate

c o m p o u n d that o r i g i n a t e d f r o m t h e brick

7 E f f l o r e s c e n c e on the face of b r i c k m a s o n r y walls adversely

affects t h e a p p e a r a n c e of the w a l l b u t does not u s u a l l y a d v e r s e l y affect

t h e strength a n d d u r a b i l i t y of the wall However, forces f r o m c o n t i n u i n g

e f f l o r e s c e n c e deposits in b r i c k pores and f r o m c o n f i n e m e n t of

e f f l o r e s c e n c e deposits on t h e face of bricks by "waterproofing" a n d w a t e r

"repellent" coatings applied to the b r i c k w o r k and by the g l a z e on the

glaze bricks can cause spalling and d e t e r i o r a t i o n of the bricks

8 F r o m a practical standpoint, the potential for e f f l o r e s c e n c e

c a n n o t be t o t a l l y e l i m i n a t e d from b r i c k m a s o n r y walls e x p o s e d to the

w e a t h e r b e c a u s e e f f l o r e s c e n c e causing salts cannot be t o t a l l y e l i m i n a t e d

f r o m the m a t e r i a l s u s e d to construct b r i c k m a s o n r y w a l l s and b e c a u s e brick

m a s o n r y w a l l s are not impermeable to water

9 The p o t e n t i a l for e f f l o r e s c e n c e d e v e l o p m e n t on b r i c k m a s o n r y

w a l l s can be r e d u c e d by the following:

a P r e c o n s t r u c t i o n t e s t i n g of brick m a n u f a c t u r e d for the

specific b u i l d i n g to evaluate the e f f l o r e s c e n c e p o t e n t i a l of the brick

The p r e c o n s t r u c t i o n t e s t i n g should include the A S T M C 67 e f f l o r e s c e n c e

test, t h e A S T M C 67 absorption tests used to d e t e r m i n e b r i c k saturation

coefficient, the A S T M C 67 IRA test, and w a t e r e x t r a c t i o n of p u l v e r i z e d

b r i c k for analysis for sulfate, alkalis, calcium, and magnesium

b U t i l i z a t i o n of details that reduce w a t e r p e n e t r a t i o n into

t h e b r i c k w o r k a n d details that c o l l e c t a n d d r a i n w a t e r that has p e n e t r a t e d

t h e b r i c k w o r k o u t of the w a l l as q u i c k l y as possible T h e s e details

i n c l u d e t h e u s e of d r a i n a g e type walls w i t h a p r o p e r flashing a n d w e e p

s y s t e m at b a s e of wall, above openings, above shelf angles, and b e l o w

w i n d o w sills and copings

c Proper c o n s t r u c t i o n of b r i c k w o r k walls that results in

m i n i m a l w a t e r penetration Such a w a l l should have good b o n d and full

c o n t a c t b e t w e e n b r i c k and mortar, joints that are c o m p l e t e l y filled w i t h

mortar, p r o p e r l y tooled c o n c a v e or v - g r o o v e joints, and m o r t a r that did

n o t freeze during c o l d w e a t h e r construction To e n h a n c e b o n d b e t w e e n

bricks and mortar, bricks w i t h IRA greater than 30 g a l l o n s / m i n u t e p e r 30

square in (30 g a l l o n s / m i n u t e p e r 194 square cm) should be w e t t e d p r i o r to

laying

p e r f o r m e d by B r o w n and Matthys and our experience have i n d i c a t e d that the

u s e of p o r t l a n d c e m e n t - l i m e m o r t a r w i l l p r o d u c e m a s o n r y w a l l s that are

p e r h a p s m o r e w a t e r t i g h t than walls c o n s t r u c t e d w i t h m a s o n r y cement

mortars T h e m o r e w a t e r t i g h t a w a l l is, the less p o t e n t i a l it has to

effloresce

11 Design elements that enhance the p o t e n t i a l for d e v e l o p m e n t of

e f f l o r e s c e n c e and that should be avoided include b r i c k w o r k sills,

b r i c k w o r k copings, b r i c k pavements w i t h m o r t a r e d joints, and b r i c k w o r k

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REFERENCES

Products Institute, Washington, DC, 1950, p p 48

[2] "Efflorescence Causes and Mechanisms, Part I of II," T e c h n i c a l Note

23 Revised, B r i c k Institute of America, Reston, VA, M a y 1985, pp 1 [~] Plummer, H a r r y C B r i c k and Tile Enqineerinq, S t r u c t u r a l Clay Products Institute, Washington, DC, 1950, p p 48

[4] Brownell, W a y n e E "The Causes and Control of E f f l o r e s c e n c e on Brickwork" Research Report Number 15, Structural Clay Products Institute, McLean, VA, August 1969, pp 2

[5] Brownell, W a y n e E "The Causes and C o n t r o l of E f f l o r e s c e n c e on Brickwork" R e s e a r c h R e p o r t N u m b e r 15, Structural Clay Products Institute, McLean, VA, A u g u s t 1969, pp 6

[6] Brownell, W a y n e E "The Causes and Control of E f f l o r e s c e n c e on Brickwork" Research Report N u m b e r 15, Structural Clay Products Institute, McLean, VA, A u g u s t 1969, pp 9

[~] Brownell, W a y n e E "The Causes and Control of E f f l o r e s c e n c e on Brickwork" R e s e a r c h Report Number 15, S t r u c t u r a l Clay Products Institute, McLean, VA, A u g u s t 1969, pp 10

[8] Brownell, W a y n e E "The Causes and Control of E f f l o r e s c e n c e on Brickwork" Research Report Number 15, Structural Clay Products Institute, McLean, VA, A u g u s t 1969, p p 10

[_9] Brownell, W a y n e E "The Causes and Control of E f f l o r e s c e n c e on Brickwork" Research Report Number 15, Structural Clay Products Institute, McLean, VA, A u g u s t 1969, pp 17

[I0] Brown, Russell H "Effect of M o r t a r on W a t e r P e r m e a n c e of Masonry" Proceedinus of N o r t h American M a s o n r y Conference, U n i v e r s i t y of Colorado, Boulder CO, A u g u s t 1978, pp 115-8

[11] Matthys, John H "Conventional M a s o n r y M o r t a r Investiqation",

U n i v e r s i t y of Texas, Arlington, TX, 1988 N a t i o n a l Lime Association, Arlington, VA, pp 7

[12] Gillam, Kenneth "Effect of Sand on W a t e r Permeance of Masonry" Proceedinqs of the North A m e r i c a n M a s o n r y Conference, U n i v e r s i t y of Colorado, Boulder, CO, A u g u s t 1978, pp 118-1

[13] Ribar, J W., "Water Permeance of Masonry: A L a b o r a t o r y Study" Masonry: Materials, Properties, and Performance, A S T M STP 778, J G

Philadelphia, PA, 1982, p p 200

[14] Ritchie, T and Davison J I "Factors A f f e c t i n g Bond Strength and

R e s i s t a n c e to M o i s t u r e Penetration of Brick Masonry" S y m p o s i u m On

M a s o n r y Testinq, A S T M special technical p u b l i c a t i o n No 320, A m e r i c a n Society for Testing and Materials, Philadelphia, PA, 1962, p p 16

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D I S C U S S I O N

J Carrier I and R Evans 2 (written d i s c u s s i o n ) - - I n an attempt to

discern the cause of efflorescence, potential sources of soluble salts are

carbonate 'efflorescence' originates from the mortar." tend to exemplify

products, including materials used to form mortar and concrete block, may

includes sulfates, as well as calcium hydroxide, that may be deposited on

manufacture of cement may be chemically altered during hydration, other materials used to make cementitious products, including slag, pumice, and other aggregates, may contribute to the sulfate content of the brick wall

sulfates, even after hydration [3]

efflorescence potential of brick, it is virtually impossible to eliminate

has been used for decades to determine the efflorescence potential of brick itself, while further research has provided other tests to determine

results of these tests are often used as a basis for accepting or

other products, such as mortar, block, or even exterior wall board that are used in the same wall system because each of the products inherently produce soluble salts, including sulfates

The relatively high percentage of sulfate (50%) found in the 43 samples appears to give foundation to the reasoning for added brick

means that more than one sample was taken from individual buildings

efflorescence on a specific building; however, duplication of samples must

be considered when determining the overall efflorescence potential of one

samples were from different areas of the building), such double sampling (or duplication) may significantly effect the final percentage of sulfates

in relation to other salts, while incorrectly concluding that sulfates form the brick are the major cause of efflorescence

~Design advisor, Glen-Gery Corporation, Baltimore MD

2Quality assurance manager, Glen-Gery Corporation, Shoemakersville,

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DISCUSSION ON REDUCING EFFLORESCENCE POTENTIAL 19

In n e w brick masonry, brick and mortar are only two parts of a wall

mortar, e f f l o r e s c e n c e due to the deposit of sulfates m a y well be caused by

the b r i c k or mortar, but a true brick wall is r e l a t i v e l y u n c o m m o n in

appear on the face of n e w b r i c k w o r k f r o m many sources In order to

determine the actual source of efflorescence salts, each element of the

system, and it's potential to supply soluble salts and/or moisture to the

rest of the wall system must be considered

Journal of the American Ceramic Society, Vol 40, No 7, July

1957, pp 240-243

[2] Morrish, C F and Johnston, R., "A Survey of Recent R e s e a r c h

Into the Control of E f f l o r e s c e n c e in Concrete Masonry,"

Technical Report 52, Washington, Nov 1980

by M a s o n r y Mortars," Journal of the American Ceramic Society,

Vol 38, No i0, Oct 1955, pp 362-366

Chin, I R and Petty, L (Author's closure) In the 24 projects

i n v e s t i g a t e d and reported on in this paper, wall elements o t h e r than b r i c k

and m o r t a r w e r e either not present in the wall or were found not to have

and Evans that elements, other than b r i c k and mortar, "of a b u i l d i n g wall

m a y c o n t r i b u t e in part, if not all, of the soluble salt d e p o s i t e d on or

w i t h i n the masonry" was, therefore, not s u b s t a n t i a t e d by our data

w i t h respect to sulfates in p o r t l a n d cement, h y d r a t i o n causes their

i n c o r p o r a t i o n in the m o r t a r primarily as ettringite, w h i c h is only

g e n e r a l l y p r o d u c e no noticeable sulfate efflorescence

Carrier and Evans imply that w e found 50 percent sulfate in our

samples contain some sulfate form of efflorescence

We did take m o r e than one e f f l o r e s c e n c e sample from some of the

projects O f t e n this was done because the e f f l o r e s c e n c e in d i f f e r e n t

areas of the b u i l d i n g is v i s u a l l y not the same texture and a p p e a r a n c e or

is l o c a t e d at different locations on the wall (below b e d joint, on face of

brick, etc.) The e f f l o r e s c e n c e of the set of samples r e m o v e d from each

of the buildings w h e r e m u l t i p l e samples were removed was found to be

e i t h e r c a l c i u m carbonate only or sulfate only, or one sample of the set is

a b u i l d i n g by b u i l d i n g basis, the e f f l o r e s c e n c e we e x a m i n e d was d e t e r m i n e d

to be as follows:

I C a l c i u m carbonate "efflorescence" was found by itself in 31

p e r c e n t of the buildings investigated

2 Sulfate e f f l o r e s c e n c e was found by itself in 52 p e r c e n t of the

buildings investigated

The e f f l o r e s c e n c e samples removed from the r e m a i n i n g 17 percent of

t h e b u i l d i n g s i n v e s t i g a t e d were found to be c a l c i u m carbonate, sulfate,

chloride, or glycolate based, with different e f f l o r e s c e n c e appearing at

d i f f e r e n t locations on each of the buildings

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DISCUSSION ON REDUCING EFFLORESCENCE POTENTIAL

DISCUSSION

21

the projects would be a helpful addition to the paper The addition of the following citation to the references may be useful:

Grimm, Clayford, T.: "Water Permeance of Masonry Walls: A Review

of the Literature," Masonry: Materials, Properties, and Performance, ASTM STP 778, American Society for Testing and Materials, Philadelphia,

1982, pp 178-199

Chin, I R and Perry, L (Author's closure)

States Where Efflorescence Samples Were Obtained

~Consulting architectural engineer, 1904 Wooten Drive, Austin, TX

78757

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a n d w h i c h p r o v i d e a d u r a b l e wall a s s e m b l y that is e x p e c t e d to r e t a i n its

w e a t h e r r e s i s t a n c e and t h e r m a l p r o p e r t i e s for the life of the wall It

is p r o p o s e d that a p r o p e r l y s e a l e d air b a r r i e r m e m b r a n e be a p p l i e d at

the b a c k of t h e c a v i t y a n d that g l a s s f i b e r d r a i n a g e i n s u l a t i o n be

i n s t a l l e d in t h e cavity, the full d e p t h of the cavity

K E Y W O R D S : air b a r r i e r , air i n f i l t r a t i o n , b r i c k veneer, flashing,

p r e s s u r e e q u a l i z i n g , rain screen, t h e r m a l bridge, w a t e r p e n e t r a t i o n

B r i c k v e n e e r w a l l s have b e e n u s e d e x t e n s i v e l y for m a n y years,

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PIPER AND KENNEY ON BRICK VENEER WALLS 23

C O M M O N D E F I C I E N C I E S

The p r o b l e m the a u z h o r s are m o s t o f t e n a s k e d to i n v e s t i g a t e on

b r i c k v e n e e r w a l l s is w a t e r p e n e t r a t i o n t h r o u g h the m a s o n r y a n d into the

w a t e r c a n flow off the ends a n d into a b u t t i n g c o n s t r u c t i o n

9 F l a s h i n g that is not s e c u r e d to the b a c k of the c a v i t y a l l o w s w a t e r

t h a t has b r i d g e d the c a v i t y a b o v e to run d o w n the face of the s h e a t h i n g

a n d e n t e r b e h i n d the flashing

9 M o r t a r d r o p p i n g s that fill the c a v i t y can b l o c k w e e p h o l e s a n d c a u s e

w a t e r to b a c k - u p o v e r the top of the f l a s h i n g or t h r o u g h p o o r l y s e a l e d

laps M o r t a r d r o p p i n g s s e v e r a l i n c h e s d e e p are o f t e n f o u n d in v e n e e r

walls

9 D a m a g e d , d e t e r i o r a t e d , or i m p r o p e r l y i n s t a l l e d g y p s u m s h e a t h i n g a n d

v o i d s a n d c r a c k s in c o n c r e t e b l o c k w o r k a l l o w air m o v e m e n t into a n d out

of the b a c k - u p wall Warm, m o i s t air e x f i l t r a t i n g the b u i l d i n g can

c a v i t y to c i r c u l a t e a r o u n d the i n s u l a t i o n , n e g a t i n g its t h e r m a l value

T h i s c a n also c a u s e a b r i d g e for m o i s t u r e to c r o s s the cavity

T h e s e are all c o m m o n p r o b l e m s seen by the a u t h o r s a n d r e p o r t e d

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24 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

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w i t h o u t r u p t u r i n g o v e r joints b e t w e e n a b u t t i n g m a t e r i a l s such as the top

of a n o n - b e a r i n g m a s o n r y wall and a b e a m or o v e r the e d g e of f l o o r

slabs T h e y are also m o r e d i f f i c u l t to seal at p e n e t r a t i o n s , a r o u n d

w i n d o w s , a n d o v e r e x p a n s i o n joints W h e n a p p l i e d at less t h a n the

r e c o m m e n d e d t h i c k n e s s , t h e y have v e r y l i t t l e a b i l i t y to b r i d g e cracks

T h e y can be u s e d s u c c e s s f u l l y in c o m b i n a t i o n w i t h c o m p a t i b l e s h e e t

m e m b r a n e s w h e n the l i q u i d - a p p l i e d or m a s t i c p r o d u c t is u s e d o v e r s o l i d

a r e a s a n d the sheet m e m b r a n e is u s e d to span voids and joints a n d to

seal the air b a r r i e r to flashing, lintels, and p e n e t r a t i o n s

The h e a v i e r sheet m e r ~ r a n e s can also be u s e d as f l a s h i n g T h e y

a r e i n s t a l l e d c o n t i n u o u s l y f r o m the b a c k - u p b l o c k or s t u d wall o v e r the

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2 8 MASONRY: DESIGN AND CONSTRUCTION, PROBLEMS AND REPAIR

of the b i t u m e n or d e t e r i o r a t i o n due to e x p o s u r e to u l t r a v i o l e t light

The air b a r r i e r m e m b r a n e s h o w n in Fig 3 was a p p l i e d to the

s h e a t h i n g , t u r n e d into the w i n d o w opening, a n d s e a l e d to the framing

a h e a d of the b r i c k work A f t e r the w i n d o w s w e r e installed, s e a l a n t was

a p p l i e d to seal the p e r i m e t e r of the w i n d o w frame to the air b a r r i e r

P r e - c o m p r e s s e d , e x p a n d i n g f o a m seal t a p e s or f o a m e d - i n - p l a c e u r e t h a n e

a r e a l s o a c c e p t a b l e p r o d u c t s for this p u r p o s e The c o m p r e s s e d f o a m

s e a l a n t t a p e s w o r k best w i t h smooth, r e g u l a r surfaces, w h i l e the

u r e t h a n e f o a m is p r e f e r r e d with i r r e g u l a r or r o u g h t e x t u r e d s u r f a c e s

W h e n the w i n d o w s are i n s t a l l e d b e f o r e the b r i c k veneer, the air b a r r i e r

m e m b r a n e c a n be s e a l e d d i r e c t l y to t h e w i n d o w frame (Fig 4) Doors,

ducts, air c o n d i t i o n i n g sleeves, and o t h e r p e n e t r a t i o n s m u s t a l s o be

Trang 39

S H E A T H I N G

W A L L S Y S T E M

T h i s d e t a i l is d r a w n for w i n d o w i n s t a l l a t i o n p r i o r to m a s o n r y

work F o r w i n d o w s i n s t a l l e d a f t e r m a s o n r y w o r k is c o m p l e t e ,

t h e air b a r r i e r s h o u l d be t u r n e d into the w i n d o w o p e n i n g a n d

s e a l a n t a p p l i e d b e t w e e n the air b a r r i e r a n d w i n d o w frame

FIG 4 - - W i n d o w jamb

The w a l l air b a r r i e r m u s t be c o n t i n u o u s w i t h the a i r b a r r i e r at

the roof, soffit, a n d s i m i l a r c h a n g e s in plane V e r t i c a l j o i n t s b e t w e e n

b r i c k v e n e e r a n d a b u t t i n g c o n s t r u c t i o n n e e d to be s e a l e d at the a i r

b a r r i e r to p r e v e n t h o r i z o n t a l m o v e m e n t of w a t e r a n d air f r o m the c a v i t y

into the a d j a c e n t wall c o n s t r u c t i o n This is e s p e c i a l l y i m p o r t a n t w h e n

the a b u t t i n g w a l l c o n t a i n s a c a v i t y that c o u l d a l l o w air a n d m o i s t u r e

W a l l air b a r r i e r is c o n t i n u o u s over top of f r a m i n g a n d

c o n n e c t s w i t h roof air b a r r i e r , w h i c h is g e n e r a l l y b u t not

a l w a y s the r o o f m e m b r a n e

FIG 5 - - P a r a p e t d e t a i l

Trang 40

C a v i t v I n s u l a t i o n

O n e of the m o s t d i f f i c u l t (and o f t e n u n s u c c e s s f u l ) c o n s t r u c t i o n

q u a l i t y c o n t r o l e f f o r t s is to a s s u r e a c l e a n c a v i t y w i t h u n o b s t r u c t e d

f l o w tO the f l a s h i n g and weeps If the c a v i t y i n s u l a t i o n p r o v i d e s

d r a i n a g e a n d fills the full d e p t h of the cavitY, 3a clean, m o r t a r free

c a v i t y is a s s u r e d T h r e e p o u n d d e n s i t y (50 k g / m ) s e m i - r i g i d g l a s s

f i b e r i n s u l a t i o n p r o v i d e s g o o d d r a i n a g e (the g l a s s f i b e r s are all

o r i e n t e d v e r t i c a l l y a n d m o i s t u r e will not m o v e p e r p e n d i c u l a r to the face

o f the wall) a n d air flow t h r o u g h the i n s u l a t i o n for p r e s s u r e

e q u a l i z a t i o n a n d v e n t i n g This p r o d u c t has b e e n u s e d for b e l o w g r a d e

f o u n d a t i o n i n s u l a t i o n a n d d r a i n a g e for a p p r o x i m a t e l y ten y e a r s in the

U.S a n d Canada The m a s o n r y c a v i t y is a m u c h less s e v e r e e x p o s u r e

b e c a u s e t h e r e is less w a t e r and no soil p r e s s u r e on the i n s u l a t i o n

The i n s u l a t i o n is i n s t a l l e d b e t w e e n the b r i c k a n c h o r s a h e a d of

t h e b r i c k work It is e a s i l y cut to fit o v e r an a n c h o r w h e r e a d d i t i o n a l

ties are used, such as a r o u n d w i n d o w o p e n i n g s T h e g l a s s f i b e r

i n s u l a t i o n is m o r e f l e x i b l e and e a s i e r to i n s t a l l w i t h t i g h t j o i n t s t h a n

are r i g i d f o a m boards B e c a u s e the i n s u l a t i o n is the full t h i c k n e s s of

the cavity, m o r t a r c a n n o t fall into the cavity, a n d the b a s e of the

c a v i t y will r e m a i n c l e a n a n d free d r a i n i n g A c l e a n c a v i t y is a s s u r e d

w i t h o u t a n y s p e c i a l e f f o r t by the masons Pull boards, b r i c k r e m o v a l to

c l e a n out the cavity, pea gravel, a n d o t h e r s p e c i a l w o r k a n d i n s p e c t i o n s

are e l i m i n a t e d O n c e the i n s u l a t i o n is i n s t a l l e d on the flashing, the

w e e p s c a n n o t b e c o m e b l o c k e d by m o r t a r d r o p p i n g into the cavity

i n s u l a t i o n c o m p l e t e l y f i l l i n g the c a v i t y and i n s t a l l e d p r i o r to the

Tiêu đề	Masonry: Design and Construction, Problems and Repair
Tác giả	John M. Melander, Lynn R. Lauersdorf
Trường học	University of Washington
Chuyên ngành	Masonry
Thể loại	Bài báo
Năm xuất bản	1993
Thành phố	Philadelphia

Định dạng
Số trang	437
Dung lượng	8,76 MB

Astm stp 1180 1993

90 MASONRY: DESLGN AND CONSTRUCTION, PROBLEMS AND REPA{R

FLANAGAN ET AL. ON HOLLOW CLAY TILE INFILLED FRAMES 97