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(A NBS TECHNICAL NOTE 883

U.S. DEPARTMENT OF COMMERCE/ National Bureau of Standards

Waterproofing Materials

for Masonry

100

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NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3 ) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology,

the Institute for Computer Sciences and Technology, and the Office for Information Programs.

THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United

States of a complete and consistent system of physical measurement; coordinates that system

with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of a Center for Radiation Research, an Office of Measurement Services and the following divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Nuclear

Sciences ° — Applied Radiation " — Quantum Electronics a — Electromagnetics 3 — Time

and Frequency " — Laboratory Astrophysics " — Cryogenics 1

. THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measurement, standards, and data on the properties of well-characterized materials needed by industry, commerce, educational institutions, and Government; provides

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Environment * — Technical Evaluation and Application * — Fire Technology.

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divisions: Computer Services — Systems and Software — Computer Systems Engineering — Information Technology.

THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and

accessibility of scientific information generated within NBS and other agencies of the Federal Government; promotes the development of the National Standard Reference Data System and

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organizational units: Office of Standard Reference Data — Office of Information Activities — Office of Technical

Publications — Library — Office of International Relations.

1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, DC. 20234.

2 Part of the Center for Radiation Research.

3 Located at Boulder, Colorado 80302.

« Part of the Center for Building Technology.
'IONAL BUBEAQ

P STANDARDS

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14 1075,

Waterproofing Materials for Masonry

~t-cchn'<u%$. VLvk> to&>

753

-i et Elizabeth J. Clark,

Paul G. Campbell and

Geoffrey Frohnsdorff

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

Prepared for Office of Policy Development and Research Department of Housing and Urban Development

Washington, D.C. 20410

4**1 °

F

Co.

°*£M Of

U.S. DEPARTMENT OF COMMERCE, Rogers C. B. Morton, Secretary

James A. Baker, III, Under Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

(j^ NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

Issued October 1975
National Bureau of Standards Technical Note 883

Nat. Bur. Stand. (U.S.), Tech. Note 883, 86 pages (Oct. 1975) CODEN: NBTNAE

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1975

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Order by SD Catalog No. 03.46:883). Price 81.45 (Add 25 percent additional for other than U.S. mailing).
TABLE OF CONTENTS

ABSTRACT 1

1. INTRODUCTION 2

1 . 1 Background . 2 1 . 2 Obj ectives 5 1 . 3 Approach 5

2

.

EXPERIMENTAL 7

2.1 Materials Selection 7 2.1.1 Waterproofing Materials 7 2.1.2 Masonry Units 7 2 . 2 Screening Test Methods 8

2.2.1 Water Absorption 8

2.2.1.1 Untreated Masonry Materials 8

2.2.1.2 Waterproofed Masonry Materials 9 2.2.2 Water Vapor Transmission 9 2.2.3 Resistance to Efflorescence..'. 10

2.2.4 Resistance to Humidity 11

2.2.5 Resistance to Accelerated Weathering 11

2.2.6 Outdoor Exposures 12

2.2.7 Resistance to Wind-Driven Rain 12

2.2.8 Exposure to Hydrostatic Pressure 13

2.2.9 Methods of Application 14

3

.

RESULTS AND DISCUSSION 14

3 . 1 Materials 14

3.1.1 Waterproofing Materials 15

3.1.2 Masonry Materials 15

3.2 Initial Screening Tests 15

3.2.1 Water Absorption 25

3.2.2 Water Vapor Transmission 29

3.2.3 Resistance to Efflorescence 29

3.2.4 Appearance , 29

3.3 Second Phase Screening Tests 35

3.3.1 Resistance to Humidity 37

3.3.2 Resistance to Accelerated Weathering 37

3.3.3 Outdoor Exposure 42

3.4 Mortar Joint Evaluations 42

3.4.1 Resistance to Wind-Driven Rain 42

3.4.2 Exposure to Hydrostatic Pressure 44

3 . 5 Methods of Application 45

4. FIELD SURVEY 46

in
TABLE OF CONTENTS (continued)

Page

5. RECOMMENDATIONS FOR THE SELECTION AND APPLICATION OF

CLEAR WATERPROOFING MATERIALS FOR MASONRY 47

6

.

SUMMARY AND CONCLUSIONS 48

7

.

ACKNOWLEDGMENTS 51

8

.

REFERENCES 52

APPENDIX A Field Survey of Application and Performance of

Waterproofing Materials 54

APPENDIX B Proposed Waterproofing Survey for Clear

Waterproofing Agents 58

APPENDIX C Recommended Tentative Performance Criteria for

the Selection of Clear Waterproofing Materials for Use on Masonry Surfaces 62

APPENDIX D Theoretical Considerations of Water Flow through

a Pore in a Wall 68

APPENDIX E Calculations for Theoretical Consideration of

Water Flow through a Pore 75

IV
FIGURES

Page

1 Masonry Wall Above Grade Showing the Usual Direction

of Moisture Movement 3

2 A Section of a Clay Brick Wall Exhibiting Several Types

o f Openings 4

3 A Section of a Clay Brick Wall Having a Settlement Crack

and an Incompletely Filled Joint 6

4 Waterproofed Brick Samples from Efflorescence Test 30

5 Brick Samples from Efflorescence Test 31

6 Masonry Units Illustrating Changes in Appearance Caused

by Waterproofing Materials Nos. 1-10 34

7 Accelerated Weathering Exposure of Waterproofing

Materials Containing No Silicone Resins 40

8 Accelerated Weathering Exposure of Waterproofing

Materials Containing Silicone Resins 41

Dl Model of a Masonry Wall 69

D2 Model of a Pore 70

D3 The Breakthrough Pressure for Water in Cylindrical Pores

and Its Dependence on the Contact Angle 72

D4 Rate of Flow of Water Through a Wall 74
TABLES

Page

1 Information from Manufacturer's Literature or Label

for Waterproofing Materials 16

2 Water Absorption of Coated Lightweight Block Slabs 22

3 Water Absorption, Water Vapor Transmission, and

Efflorescence Tests on Coated Brick Substrate 27

4 The Effects of Waterproofing Materials on the Appearance

o f Masonry 32

5 15 Waterproofing Materials for the Second Phase of

Testing 36

6 Water Absorption After Exposure to High Humidity with

Condensation 38

7 Water Absorption After Exposure in Weather-Ometer 39

8 Water Absorption After Exposure Outdoors 43

9 Water Absorption on Masonry Substrates Having Waterproofing Materials Applied by Different Application

Procedures 46

10 Results of Screening Tests Related to the Performance

Criteria 49

vx
Waterproofing Materials for Masonry

Elizabeth J. Clark, Paul G. Campbell and

Geoffrey Frohnsdorff

ABSTRACT

The initial effectiveness and durability characteristics of

fifty-five clear masonry waterproofing materials were evaluated

using laboratory tests. This report contains the results of initial

performance tests including water absorption, water vapor transmission, resistance to efflorescence and change in appearance. Durability tests, including periodic measurement of water absorption

after exposures to accelerated weathering and outdoor exposures,

were also conducted. Based on test results, performance criteria

for clear waterproofing materials were developed. In addition,

recommendations for the application of waterproofing materials were

formulated. Finally, the report contains a summary of a survey

concerning field experiences with waterproofing and a brief theoretical discussion of water flow.

Key words: Accelerated weathering; durability of waterproofing

materials; masonry; performance criteria; waterproofing materials;

water repellent materials.
1. INTRODUCTION

1.1 Background

Water damage to buildings or their contents is a serious problem.

In the case of masonry buildings, water infiltration may be the result

of the porosity of the masonry units and the mortar joint system, settlement or other cracks, open construction or expansion joints, defective

flashings, roof leakage, etc. The two main methods of treatment to

reduce or eliminate water infiltration are: a) reduction or elimination

of the openings due to pores or cracks; and b) application of a water

repellent treatment to the surface.

Because of its needs for waterproofing treatments for use on exterior masonry surfaces, the Department of Housing and Urban Development (HUD) requested the National Bureau of Standards (NBS) to perform

studies on clear waterproofing materials for masonry surfaces and to

develop performance criteria for the selection of such waterproofing

materials.

While it is virtually impossible to completely exclude water from a building under all conditions, the proper use of waterproofing materials

can minimize water infiltration. Waterpropf ing materials may be divided

into two types, waterproof ers and water repellents. In a general

definition of terms, Maslow [1]* identified a waterproofing material as an impervious coating, e.g., coal tar, asphalt and some paints, which

seals the surface to the infiltration of water and water vapor, while a water repellent is a material, e.g., aluminum stearate, and silicones,

that penetrates the surface and permits the movement of water vapor but

not the infiltration of water. In general, the clear waterproofing

materials used above grade are water repellents. In this report, the

single term "waterproofing" material is used to cover both materials

that penetrate the surface and those that form a film on it.

Because of the higher relative humidity indoors at most times of

the year, the usual direction of moisture movement through walls above

grade is interior to exterior as illustrated in Figure 1 [2]. For this

reason, and to prevent accumulation of moisture within the wall, the

interior surface should be relatively impermeable, while the exterior

surface should be permeable enough to permit transpiration of water

vapor to the outside while resisting the inward passage of water. This

applies even to waterproofed surfaces.

Figures in brackets indicate references.
Interior

Impermeable Film

Exterior

Permeable Film

Figure 1. Masonry Wall Above Grade Showing

the Usual Direction of Moisture

Movement.

Where it is desirable to retain the original appearance of masonry

after waterproofing, clear waterproofing materials are employed. Among

clear waterproofing treatments which have been used historically are petroleum distillates and fatty substances (oils) dissolved in mineral

spirits, aluminum stearate (with or without petroleum distillates),,

varnishes, inorganic salts, soluble soaps or glue dissolved in water [3,

4], molten paraffin [5], and emulsions and solutions of waxes and

paraffins [6]. However, it appears that none of the waterproofing

materials are fully satisfactory since new materials are continually

being introduced in attempts to improve this type of treatment. For

example, Litvin [7] included polyurethane, epoxy, aerylate, silicone and

vinyl toluene resins, as well as the older type resins, in a comprehensive

study of the soiling of clear coatings for exposed architectural concrete.

Also, the older commercially available materials are continually being

reformulated to improve their performance.

As a class, the clear materials tend to be less effective than

opaque materials such as paints because, being usually of lower solids

content than pigmented materials, they are less able to fill or bridge

large cracks and openings. Also, they are usually less resistant to

weathering. In spite of their limitations in performance, clear waterproofing treatments are of considerable value, particularly if proper

care is exercised in their selection and application.

The demands made upon waterproofing agents for masonry walls depend

upon the exposure conditions, the quality of the masonry units and the

mason's workmanship, as well as the presence of cracks or other openings,

Examples of some types of openings which may be present are shown in the

portion of the house wall seen in Figure 2. Included are: open cracks

between the mortar and brick due to loss of bond (Area C) , bricks having

cracks and voids (Areas D and E), incompletely filled joints (Area F)

,

and possible settlement cracks (Areas C and F) . Another example of

3
Figure 2. Section of a Clay Brick Wall Exhibiting Several

Types of Openings.

Area C - open cracks between the mortar and brick

due to loss of bond

Areas D, E - bricks having cracks and voids

Area F - incompletely filled joints

Area C and F - possible settlement cracks
settlement cracks and incompletely filled joints is illustrated in

Figure 3. The open cracks shown in this figure are larger than 0.05 cm

(0.02 in) and Anderegg [6] has commented on the difficulty of sealing

openings wider than this by any type of waterproofing treatment. It

should also be noted that Fishburn et al. [5], Kanarowski [8], and

Kruger and Loubser [9] have stated that workmanship involving the mortar

joints affects the permeability of walls more than any other factor.

1.2 Objectives

The objectives of this study are:

1. To evaluate by laboratory methods the initial effectiveness and durability characteristics of commercially available,

clear, waterproofing materials for masonry.

2. To survey field application and performance of the

waterproofing treatments.

3. To study the methods of application of clear waterproofing materials and to prepare recommendations for their application.

4. To recommend performance criteria for clear waterproofing

materials for masonry surfaces.

1.3 Approach

To evaluate the initial effectiveness and durability characteristics

of waterproofing materials, small-scale laboratory tests which indicated

the resistance of coated masonry specimens to the infiltration of water

were carried out. These tests included water absorption, water vapor

transmission, and resistances to efflorescence, wind-driven rain and

hydrostatic pressure. Accelerated and outdoor weathering exposure tests were used to assay waterproofing performance over an extended time

period. These tests were similar to the performance tests required for

the quality assurance of other waterproofing materials, e.g., Fed. Spec.

SS-W-110C [10], Fed. Spec. TT-C-555B [11]. The masonry materials used

were clay brick and concrete block such as are frequently used in housing.

The clear waterproofing materials covered most types which are commercially

available.

The laboratory tests were designed to screen materials for effectiveness and durability and were not intended to exactly duplicate actual

use conditions. In some respects, the laboratory tests were more severe

than real life situations. However, these tests were useful for the

comparison of the performance properties of different waterproofing

materials and provided a basis for the development of preliminary performance criteria which are given in Appendix C of this report.
A

B

Figure 3. A Section of a Clay Brick Wall.

Area A - settlement crack

Area B - incompletely filled joint
A brief survey of field experience with waterproofing treatments

was made by means of discussions with maintenance officials at HUD

regional and area offices. The results which are commented upon in

Section 4 are reported in Appendix A.

To study the methods of application, laboratory tests using brush,

roller, air spray and airless spray application techniques were used.

Based upon the laboratory results and on the survey of field application

and performance, recommendations for waterproofing application are given

in Section 5.

2 . EXPERIMENTAL

2.1 Materials Selection

2.1.1 Waterproofing Materials

Fifty-five clear waterproofing materials were assembled for this

study. The percent solids was determined by the procedure described in

Fed. Test Method Std. No. 141a, Method 4041.1 [12]. The resin content

of the solids was then identified as to generic type by infrared analysis.

For materials with organic solvents, the procedure involved casting a film of the nonvolatile vehicle dissolved in acetone on a sodium chloride

disc. A silver chloride disc was substituted when water-thinned materials

were examined. The thickness of the sample was adjusted to give a background transmission between 85 and 95 percent. The identity of the

nonvolatile vehicle was deduced by comparison with published spectra

[13].

2.1.2 Masonry Units

Three kinds of masonry units representing types frequently used in

the United States were chosen for this study. They were lightweight

concrete block, dense aggregate concrete block and clay brick units.

The concrete block units had two cores and nominal dimensions of 20 cm x

20 cm x 40 cm (8 in x 8 in x 16 in). The dry weights were approximately

14 kg (31 lb) and 22 kg (48 lb) . Water absorption properties for the

concrete block units were determined by test procedures as described in

ASTM C 140-70 [14]; they are as follows: lightweight aggregate 12.9%,

dense aggregate 4.5%. The brick units were commercially available good

quality three core brick used in building construction. The nominal

dimensions were 9 cm x 19 cm x 5 cm (3 1/2 in x 7 1/2 in x 2 in). The
dry weight was about 1.7 kg (3 3/4 lb). Their properties as determined

according to ASTM C 67-73 [15] are given below:

Net Compressive

Solid Strength

Area (Gross Area)

%

psi

79.7 13085

MPa

90.02

Percent

Absorption

24 h 5 h

cold boil

Saturation

Coefficient

7.1 9.1 0.76

Initial Rate of

Absorption

g/30 in 2 /min

(g/193.5 cm2 /min)

21.1

Face slabs were prepared from these samples for the various test procedures. The lightweight block units were cut into specimens of two sizes

having dimensions of about 9.5 cm x 19 cm x 4 cm (3 3/4 in x 7 1/2 in x

1 1/2 in) and 19 cm x 39 . 5 cm x 4 cm (7 1/2 in x 15 1/2 in x 1 1/2 in).

The dense aggregate units were cut into slabs of about 19 cm x 39.5 cm x

4.5 cm (7 1/2 in x 15 1/2 in x 1 3/4 in). Since the brick units were

cored and many tests involved the movement of water or salts, face slabs

approximately 6 cm x 19 cm x 3 cm (2 1/4 in x 7 1/2 in x 1 1/4 in) were

cut

.

2.2 Screening Test Methods

2.2.1 Water Absorption

The water absorption of the untreated masonry materials was determined

to establish a reference point. To compare the effectiveness of the

waterproofing agents in protecting the masonry materials from water

penetration, the water absorption test was repeated after application of

the waterproofing materials. Lightweight block and brick slabs were

used. It was found that the variation in water absorption of individual

brick or concrete block slabs was large enough so that separate water

absorption determinations for each test specimen were necessary. Water

absorption of individual brick slabs was found to vary between 5.7 and

10.2 percent.

2.2.1.1 Untreated Masonry Materials

After a 24 hour immersion in water, the wet slabs were weighed

(W ) . Then they were dried at 105 °C to a constant weight, cooled, and

reweighed (W )

. The difference in weights was the amount of water

absorbed (W ) by the untreated slab.

w. = wT7 - W^

A W D
2.2.1.2 Waterproofed Masonry Materials

The test method for determination of the water absorption of a waterproofed slab was adapted from the procedure described in Fed. Spec.

SS-W-110C, Water Repellent, Odorless, Silicone Base [10]. Instead of

immersion of the substrate in the water repellent solution for ten

seconds, the waterproofing material was brushed on four 'edges and the

2 2 uncut face of the slab at a spreading rate of 2.45 m /£ (100 ft /gal) for

2 2 lightweight aggregate block and 4.90 m /£ (200 ft /gal) for brick. Test

specimens were prepared, in triplicate for every waterproofing material.

After a one week cure at ambient laboratory conditions (about 25°C and

35% relative humidity), the coated slabs were weighed (W ) then immersed,

uncoated side up, into water. The test specimens were supported off the

base of the container to permit circulation of the water. The water

depth was maintained at 1.3 cm (1/2 in) during the test. At the end of

72 hrs , the slabs were reweighed (W )

.

" The water absorption was the

o w ratio of the water absorbed by the coated slab to the water absorbed by

the original untreated slab.

W - W

% Water Absorption = x 100

W

A

The triplicate results were then averaged to give the average water

absorption for each waterproofing material. After drying, reflectance

measurements (45°) [16] were taken at three locations on the specimen

using a photoelectric reflection meter.

2.2.2 Water Vapor Transmission

The water vapor transmission test determined the rate of movement

of moisture from the interior of a saturated specimen out through the

waterproofing material.
The brick slabs used for the water absorption test (Sec. 2.2.1.2) were completely submerged for 24 hours in water so that the top of the

slab was 0.6 cm (1/4 in) below the water surface. The brick slabs were

supported to permit free circulation of water around them. After 24

hours, the slabs were removed from the water and excess surface water

removed by blotting with a damp cloth. The untreated face of the brick

was then placed downward on a piece of aluminum foil slightly larger

than the brick slab. The foil was sealed to the brick by pouring melted

carnauba wax around its lower perimeter, then folding the foil up around

it. The weight (W_.) of the brick slab was recorded, then the slabs were

stored at ambient laboratory conditions (about 25°C and 35% relative

humidity) with circulation of air. After seven days, the slabs were

reweighed (W ) . The difference in the weights was the amount of moisture

hi lost by transmission through the waterproofing coating. The water vapor

transmission was defined as

W

B

' W

E

% Water Vapor Tramission = —

x 100

W

A

2.2.3 Resistance to Efflorescence

This test assessed the ability of a waterproofing coating to resist

the passage of salts through it and permit the formation of efflorescence.

The brick slabs from the water vapor transmission (Sec. 2.2.2) were used

for this test. The aluminum foil was removed and the slabs were air

dried to constant weight. The slabs were then placed with the uncoated

face downward to a depth of 1.3 cm (1/2 in) in a 10% aqueous sodium

sulfate solution for seven days. The liquid level was maintained constant

throughout the test. The slabs were then removed, allowed to dry and

the coated surfaces were examined for efflorescence. The coated face of

the slab was rated visually on a scale of 1 to 4 as follows: 1 heavy

efflorescence; 2 slight efflorescence; 3 no efflorescence on face but

salt residues on edges; 4 no efflorescence.

10
2.2.4 Resistance to Humidity

The purpose of this test was to determine whether the waterproofing

coatings were affected by continuous exposure to high humidity and

condensation.

After the water absorption had been determined on individual brick

face slabs according to Section 2.2.1.1, the four sides and the uncut

face were coated with a waterproofing material at a spreading rate of

2 2 4.90 m I l (200 ft /gal). Duplicate specimens were prepared for each

test material. After being allowed to cure one week at ambient laboratory conditions (about 25°C and 35% relative humidity) , the coated face

1 2/ . of the brick was exposed on a Cyclic Environmental Tester using a continuous condensation cycle and a 38 ± 2°C air temperature. Samples were removed and weighed at periodic intervals, and water absorption and

reflectance measurements were taken after six and fourteen weeks.

2.2.5 Resistance to Accelerated Weathering

The accelerated weathering test is intended to simulate natural

weathering. It was performed to determine if the effectiveness of

waterproofing materials was changed by exposure to ultraviolet light.

Brick face slabs were used as the substrate for the waterproofing

materials in this test. The water absorption of the individual brick

slabs was measured as described in Section 2.2.1.1. The brick slabs

2 2 were then coated at a spreading rate of 4.90 m /Z (200 ft /gal) on the

four edges and the uncut face and allowed to cure one week at ambient

laboratory conditions (about 25°C and 35% relative humidity) . Duplicate

test specimens were prepared. The uncoated face was protected by placing

the slab, uncoated face down, on a piece of aluminum foil and sealing

1/ Available from the Q-Panel Company, Cleveland, Ohio 44135.

2/ Certain commercial equipment, instruments or materials are identified

in this paper in order to adequately specify the experimental procedure.

In no case does such identification imply recommendation or endorsement

by the National Bureau of Standards, nor does it imply that the material

or equipment identified is necessarily the best available for the purpose

11
with melted carnauba wax. The test specimens were placed in a WeatherOmeter—, single enclosed carbon arc, exposed to a 102-18 cycle, i.e.,

102 minutes light only, 18 minutes light and water spray. At 500 hour

exposure intervals, the brick slabs were removed and water absorption

measurements made. Reflectance measurements (45°) [16] were made after

the slabs were dried to a constant weight.

2.2.6 Outdoor Exposures

The purpose of the outdoor exposures was to determine the effect of

natural weathering. The water absorptions of the individual brick slabs were measured as described in Section 2.2.1.1. The brick slabs were

2 2 coated at a spreading rate of 4.90 m /£ (200 ft /gal) on the four edges

and the uncut face and allowed to cure one week at ambient laboratory

conditions (about 25°C and 35% relative humidity). Duplicate test

specimens were prepared for each test material. The test specimens were

exposed in a horizontal position at the NBS outdoor exposure site in

Gaithersburg, Maryland, from May to November of 1974. Before being

exposed a water absorption test with a 6 hour rather than 72 hour immersion

was performed on one brick slab of each waterproofing material. At one month intervals, reflectance measurements were made and the 6 hour water

absorption test was repeated on the same brick specimen for each waterproofing material. (The 6 hour, rather than the usual 72 hour water immersion period was used in order to maximize outdoor exposure.) After six

months, all the brick slabs were retrieved and dried to a constant

weight before making reflectance measurements (45°) [16] and determining

the 72 hour water absorption.

2.2.7 Resistance to Wind-Driven Rain

This test was intended to determine the ability of a waterproofing

material to resist water penetration under pressures simulating a winddriven rain of 160.9 km/h (100 mph) . Since this is a severe test, the

1/ Available from the Atlas Electric Devices Co., Chicago, 111. 60613

12
dense aggregate block was chosen as the substrate for the preliminary

tests. Measurements were made on dense aggregate face slabs (about

19 cm x 39.5 cm x 4.5 cm [7 1/2 in x 15 1/2 in x 1 3/4 in]) following

the procedure described in Federal Specification TT-C-555B, Coating,

Textured (For Interior and Exterior Masonry) [11].

The face slabs were coated with waterproofing materials in one and

2 2 two coat applications at a spreading rate of 4.90 m /l (200 ft /gal).

The three waterproofing materials used in this test were selected to

give a variation in both solids content and generic type of resin. The

coated slabs remained on the wind-driven rain apparatus until failure

occurred. Penetration of water through the slab to the uncoated side was termed failure.

Brick wallettes were constructed of one brick width with five

mortar joints. Thus, the dimensions of the coated face were approximately

19 cm x 40 cm (7 1/2 in x 16 in) . The mortar used conformed to type N

of ASTM C 270-73 [17]. To simulate surface cracks in the mortar, half

the wallettes had two metal shims, one each of 5 cm x 0.025 mm (2 in x 1 mil)

and 5 cm x 0.1 mm (2 in x 4 mil), placed between the mortar and brick

approximately 1 cm (1/2 in) in depth of penetration. The shims were

removed before the mortar set. The specimens were prepared in triplicate

with and without the shim cracks. All the wallettes were given 2 coats

2 2 of waterproofing material [4.90 m /t (200 ft /gal)], then permitted to cure for one week. The waterproofing materials used to coat the wallettes

were: a silicone of 4.6% solids; an acrylate of 31.1% solids; and a modified silicone of 9.9% solids.

2.2.8 Exposure to Hydrostatic Pressure

The purpose of this test is the same as that of the wind-driven

rain, i.e. to determine the ability of a waterproofing material to

resist water penetration under pressures simulating a wind-driven rain

of 160.9 km/h (100 mph)

.

13
A modification of a water permeability test on concrete masonry

units described by Smith [18] was used to measure the water permeability

of the coated brick wallettes. The wallettes were prepared as described

in Section 2.2.7. The modification of the test involved construction of

a wood frame 15.2 cm (6 in) high, and 15.2 cm (6 in) wide by 34.3 cm

(13 1/2 in) long. A tank was formed by sealing the frame to the perimeter

of the coated surface of the brick wallette with a caulking compound

complying with Federal Specification TT-C-00598C [19]. Water was added

to a 12.7 cm (5 in) height and the frame was covered with plastic to

prevent evaporation of water. The loss of head of water with time and

the visual examination of the mortar joints were used to estimate the

effectiveness of the waterproofing treatment. Due to the results of the

initial tests, after the hydrostatic pressure tests were completed, half

2 2 of the wallettes had a third coat [2.45 m /l (100 ft /gal)] of waterprooi

material added and the test was repeated.

2.2.9 Methods of Application

The purpose of this investigation was to determine the relative

effectiveness of the different application methods. The methods used

for the waterproofing coatings were brush, roller, airless spray, and

conventional air spray. The techniques used to apply the coatings by

these methods were those described in Chapter 4, Painting Operations, of

Paints and Protective Coatings [20], The substrates utilized were

brick, lightweight and dense concrete block. Application was to the

vertical surfaces and the coating was applied until the surface was saturated or flooded. Two coats were applied 24 hours apart. After the

coatings were dried, the brick and lightweight aggregate block test

specimens were tested for water absorption.

3. RESULTS AND DISCUSSION

3.1 Materials

14
3.1.1 Waterproofing Materials

The waterproofing materials used in this study covered the range of

commercially available materials. The inclusion or omission of a particular product should not be considered important since the purpose of

this work was to establish criteria by which selection could be made in

the future rather than to evaluate specific waterproofing materials.

Information from the manufacturers about the spreading rates and recommended

substrates for the waterproofing materials is contained in Table 1. If

there was no information, a blank was left in the table.

All waterproofing materials were characterized by determining the

percent solids and the type of binder or resin. Infrared analysis was

used to identify the resins by generic type. The solids content and

resin components of the waterproofing coatings are listed in Table 2,

together with water absorption data which will be discussed in Section

3.2.1. In mixtures, the order of resins listed does not reflect their

content in the material as no attempt was made to determine the percent

of individual components.

Of the 55 samples received, six were two-package systems (Nos. 1,

5, 21, 29, 37, 54) and eleven were water-thinned (Nos. 1, 2, 3, 5, 11,

25, 37, 42, 45, 46, 55) and the remainder were solvent-thinned one- package materials. The major generic types found were as follows:

silicones or modified silicones (sixteen) ; acrylates (ten) ; styrene

acrylates and vinyl toluene acrylates (eight); urethanes (six); aluminum

stearate mixtures (five) ; silicone and other resin mixtures (five)

;

polyester (one); inorganic (one), as well as various resin combinations.

In general, these major types are broad classifications. The silicone or modified silicone category includes methyl silicones, methyl siliconates,

polymethyl silicic acid, and other modified silicones. The acrylates are composed of ethyl, butyl, and isobutyl acrylates plus the methacrylates

.

3.1.2 Masonry Materials

The brick and block materials used in this study were selected

because they represent a range of types of masonry units used in the

southeastern United States. Although it was recognized that the effectiveness of a product on the waterproofing of joints is an important

consideration, individual slabs were used for the screening tests.

Preparation of many specimens with uniform mortar joints would have been

difficult since workmanship plays such an important role. Brick slabs were used for most of the screening tests since, if a waterproofing

material is not effective on brick, it is unlikely to be effective on

the more porous material in a mortar joint or a concrete block.

3.2 Initial Screening Tests

Three screening tests were performed to determine which waterproofing materials were initially most effective. The primary consideration

15
Table 1

Information from Manufacturer's Literature or Label for Waterproofing Materials

Waterproofing

Sample

Substrate

(Recommended for Use On)

Spreading

Rate

(ft2/gal)

Composition

Concrete block, brick, stucco,

masonry, concrete

225 1st coat; 425 2nd

coat; If add 2nd coat,

4 b between. Two coats

recommended for opti- mum results

Water based

epoxy, 28.5%

solids (2 part)

Concrete, stucco, slate, stone, 100-300

masonry, transite, cement

plaster

Concrete, stone

Acrylic resins

water thinned

Silicone water

thinned

Brick, concrete, flagstone,

stucco, block

100-150; 2 coats

recommended for very

dense surfaces

5% silicone

Concrete, precast & poured

Brick

Stucco

Plaster, stone, tile

Limestone

Dense concrete block

120-170

70-100

80-100

200-300

175-200

60 1st coat (4 to

5 h between)

80 2nd coat

Water thinned,

2 part

Silicone, vinyl

toluene acrylate

Silicone, vinyl

toluene acrylate

Silicone, vinyl

toluene acrylate

4.7 - 5.7%

solids

16
Table 1 (continued)

Water- Substrate Spr eading Composition

proofing (Recommended for Use On) Rate

Sample (ft 2 /gal)

1st coat 2nd coat

10 Block, porous 40 80 7.5 - 9.0%

Split face block 40-50 70-80 solids

Mammoth block 60 100

Slump block 65-70

Concrete 130-150

Brick 100

Stucco 100

Stone, tile 200-300

11

12

Leathers, vinyls, plastics

Concrete

Smooth

Sandblasted

1st coat 2nd coat

200 225-250

125-150 175-200

2 coats recommended

Water thinned

Blend of

polymeric resins,

10% solids

13

Exposed Aggregate

3/8 in

3/4 in

Brick

Common

Face

Concrete block

Hard brick

Soft brick

Lightweight block

Masonry

Stucco

Asbestos shingles

150-200

160-250

150-200

200-275

150

150

100

75

150

100-150

50

6% silicones

14

15 Masonry

Stone

16 Concrete block 75-200

lightweight porous 70-75

Stucco

Brick

hard fired 150-200

soft 100-125

Stone

Concrete

Asbestos shingles (If add 2nd coat,

between)

24 h

20% poly-methyl

methacrylate

5% silicones

SS-W-00110

1?
Table 1 (continued)

Waterproofing

Sample

Substrate

(Recommended for Use On)

Spreading

Rate

(ft 2 /gal) Composition

17 Linoleum, tile, wood, concrete 150-200 Polypropylene

glycol, aliphatic

diisocyanate

copolymer, 40%

solids

18 Concrete 15.1% styrene

acrylate; 32.8%

solids

19 Stucco, brick, concrete, 75-125 if one asbestos cement, normal porosity coat only or 2 masonry, dense porosity masonry coats at 175-200 (4

h between) Saturate

surface both cases

Silicone

20 Concrete, metal, wood 550-700* Polyurethane,

33-36% solids

21

22

Stone

Brick

common

glazed, wirecut

Masonry

Concrete

precast

cast in place

Lightweight block

Brick

Concrete

Stone

350-400

150-175

350-400

350

300-350

250-300

150

180-270; On porous

surfaces 2 coats

recommended (6 h

between)

Hydrophilic

acrylic, 6-9%

solids (2 part)

Poly oxo aluminum stearate

23

24

25

Brick, mortar, concrete,

block, concrete

Dense concrete, dense brick,

mortar, stucco, wood

Brick, concrete, stone, tile,

terrazzo

100-125; 2 coats

recommended (6 h

between)

65-100; 2 coats

recommended (24 h

between)

250-2100; depending

on porosity

This application rate gives one mil thickness

18

Modified oil 15%

solids

Mineral oil

30% mineral solids,

water thinned
Table 1 (continued)

Waterproofing

Sample

Substrate

(Recommended for Use On)

Spreading

Rate

(ft2/gal)

Composition

26

27

28

29

30

31

32

33

Concrete, brick, masonry,

stucco

Masonry, brick

Terra-Cotta

Dense brick

Common brick

Cement brick

Concrete

Concrete block

Mortar

Terrazzo

Concrete, plaster, brick,

mortar, stone, stucco, terrazzo

Concrete

50-250

150-200

If not painted over,

2 coats recommended

(2 h between)

250-400

150-200

100-125

60-100

150-200

60-100

100-125

250-400

2 coats recommended for

dense surfaces (12 h

between)

250-400

300

2 coats recommended

(1 h between)

300

2 coats recommended

(1 b between)

5% silicone

5% silicone

SS-W-00110A

2 part

Modified polyester,

36% solids

15% solids

30% solids

Vinyl acrylic

modified with

hydrophobic

agents

34 Concrete

35 Concrete

36 Concrete

37 Concrete, stone, brick,

masonry block

75-100 1st coat

150-200 2nd coat

2 coats recommended

for porous surfaces

(6 h between)

Vinyl acrylic resin

Vinyl acrylic resin

Silicone type resin

with hydrophobic

agents

Acrylic, polyethylene, and

epoxy resins,

water thinned,

(2 part)

19
Table 1 (continued)

Water- Substrate

proofing (Recommended for Use On)

Sample

Spreading

Rate

(ft 2 /gal)

Composition

38

39

40

41

42

43

44

45

46

47

Masonry, concrete, cinder

block walls

Exposed concrete, asbestos

cement, cement based plasters,

exposed aggregate concrete,

jointing compounds

Brick, concrete, cinder block,

mortar, stucco, stone

Concrete

Precast

Light, sandblasted

Dense masonry brick

Dense, smooth block

Lightweight, slumpstone block

Common smooth brick

Common porous brick

Masonry, brick, concrete,

marble, painted surfaces

Concrete

Concrete

Soil

Brick, concrete, drywall,

masonite

Concrete

Poured

Precast

Precast/Exp. Agg.

Concrete block

Cinder block

Mortar

100-200

200-400

100-200

50-250*

50 1st coat

75 2nd coat

100-150

150-300

100-200

2 coats recommended

(1/2 h between)

150-200

2 coats recommended

for porous materials

Mixtures of 44-1 to 20-1 water to sample

1200-1800

250

275

300

200

125

250

Butyrate resins

Polymethyl silicic

acid, 18% solids

Polymethyl silicic

acid, 50% solids

Several organic & inorganic solids

Water based

copolymer, 26.5%

solids

Solids: chlorinated polymer

61.4%, synthetic

polymer 37.4%

ASTM C-309,

AASHO DES-M-148

Polys ilioxane

water thinned

Water based

acrylic epoxy

Blend of polymers,

resins, hydrocarbon solvents;

10% solids

* Voids larger than .020 in shall have sealer applied first.

20
Table 1 (continued)

Waterproofing

Sample

Substrate

(Recommended for Use On)

Spreading

Rate

(ft 2 /gal)

Composition

47 cont. Brick

48

49

50

51

52

53

54

55

Face

Common

Stone

Plaster & stucco

Wood

Cement, masonry, brick,

stucco, stone, asbestos

shingles

Concrete, brick, stone

Porous lightweight block

400

250

175-300

325

200-400

150

75-150, 2 coats

(24 h between) recom- mended for very coarse

or porous surfaces

Porous brick, concrete masonry 100-150

Metal, wood, stone, masonry,

stucco, concrete

1st coat 2nd coat

Soft brick 100-250 150-350

Hard brick 100-350 150-350

Clay block 75-150 100-200

Dense block 75-200 100-300

Smooth lightweight block 50-100 75-150

Split lightweight block 40-80 70-110

Slump block 50-120 75-160

Rough concrete 400 400

Smooth concrete 800 400

Silicone

SS-W-0110

5% silicone

SS-W-110B

Polyurethane

53% solids

Acrylic, 40%

solids

Silicones and

methyl methacrylate

15% solids

Fluoro copoly urea

(2 part)

Water based

modified acrylic

polyvinyl acetate

51% solids

2 coats required (2

between)

21
81.5 aery] ate 18.5

80.9 silicone or modified

silicone

4.7

Table 2

Water Absorption of Coated Lightweight Block Slabs

(Brush Application at Spreading Rate of 2.45 m2 /l (100 ft /gal))

Waterproofing Percent Water Absorption* Resin Percent

Sample 1 coat 2 coats Components Solids

1 92.5 19.5 silicone or modified 27.2

silicone, epoxy

2 91.5

3 89.5

4 92.6 10.9 silicone or modified 3.7

silicone

5 90.9 75.7 urethane 35.9

6 93.7 66.3 vinyl toluene acrylate 19.9

7 80.9 54.4 vinyl toluene acrylate 13.2

8 92.3 51.9 vinyl toluene acrylate 21.2

9 94.1 55.2 acrylate, aluminum 4.8

stearate, oil

10 82.6 45.9 acrylate, aluminum 6.8

stearate, oil

11 90.8 68.5 urethane 33.5

12 89.3 9.2 silicone or modified 6.2

silicone, oil

13 68.9 26.0 silicone or modified 4.6

silicone

14 59.3 7.2 silicone or modified 33.1

silicone

15 92.6 71.8 acrylate 17.7

16 74.7 27.3 silicone or modified 5.1

68 5 urethane

9 2 silicone or modified

silicone, oil

26 silicone

silicone

or modified

7 2 silicone

silicone

or modified

71 8 acrylate

27 3 silicone

silicone

or modified

27 9 urethane

76 2 styrene acrylate

33 3 silicone

silicone

or modified

28 1 urethane

59 1 acrylate

** aluminum stearate

17 71.4 27.9 urethane 39.7

18 92.0 76.2 styrene acrylate 30.3

19 72.3 33.3 silicone or modified 4.3

silicone

20 40.9 28.1 urethane 33.6

21 75.6 59.1 acrylate 10.1

22 93.2 ** aluminum stearate 4.9

22
Table 2 (continued)

Waterproofing Percent Water Absorption* Resin Percent

Sample 1 coat 2 coats Components Solids

23 100.3 35.7 oil, aluminum stearate 15.5

24 89.4 19.4 silicone or modified 5.6

silicone, aluminum

stearate, oil

25 92.8

26 92.6

27 59.6

28 74.0

29 72.2

30 85.8

31 71.1

32 90.5

33 94.1

34 84.2

35 94.7

36 79.4

37 92.1

38 85.2

39 42.0

silicone

40 40.9 28.0 silicone or modified 56.5

silicone

41 90.7

42 62.3

43 58.5

44 79.7

45 93.7

46 96.4

47 77.4

56 7 inorganic 25 8 60 silicone or silicone

modified 9

32 6 silicone or silicone

modified 4 6

20 6 silicone or silicone

modified 1 4

7 3 polyester 78 1 59 4 acrylate 37

45 3 aerylate 16 4

74 5 acrylate 30 8 45 8 vinyl toluene acrylate 6 6 49 1 vinyl toluene acrylate 8 66 6 vinyl toluene acrylate 12 1 53 9 silicone or silicone

modified 3 4

78 7 acrylate, hydrocarbon 20 8

36 9 acrylate 31 1 33 4 silicone or modified 18 2

61 7 aluminum stearate mixture 10

51 7 acrylate 26 1 47 3 styrene acrylate, chlorinated hycrocarbon

17 7

70 1 styrene acrylate 18 1 75 6 silicone or modified

silicone

49 3

82 7 acrylate 33 .1 41 2 silicone or modified 9 9 silicone

48 22.3 9.7 silicone or modified 53.0

silicone

23
Table 2. (continued)

Waterproofing Percent Water Absorption* Resin Percent

Sample 1 coat 2 coats Components Solids

49 79.1 17.0 silicone or modified 4.7

silicone

or modified

18.1 urethane

91.2 silicone or modified

50 87.2 18.1 urethane 33.9

51 79.4 91.2 silicone or modified 30.0

silicone, vinyl toluene

acrylate, oil

52 74.0 13.5 vinyl toluene acrylate, 43.2

silicone or modified

silicone

53 54.0 41.7 acrylate 13.1

54 94.6 75.0 urethane 8.3

55 93.6 83.5 vinyl acetate, acrylate 51.3

* The percent water absorption is the ratio of the water absorbed by the coated

test specimen to the water absorbed by the test specimen before it was coated,

** Insufficient material to apply the second coat.

24
was whether the materials would keep the water out as determined by the

water absorption test. Water vapor transmission and resistance to

efflorescence measurements were also made.

3.2.1 Water Absorption

Initially, it was intended to perform the water absorption screening tests on lightweight aggregate block slabs in accordance with the

procedure outlined in the Federal Specification for silicone waterproofing materials, SS-W-110C. The method calls for the test specimens to be

totally immersed for ten seconds in the waterproofing solution under

test. However, modification of the test method was necessary because

immersion of the substrate in waterproofing materials of different

viscosities gave widely different application rates. In addition, the

spreading rates (the areas covered by unit volumes of coating material)

resulting from immersion were usually many times greater than the

manufacturers' recommended application rates. Thus, to ensure a constant

spreading rate which approximated actual applications, the waterproofing

materials were applied by brush at selected spreading rates. A single

spreading rate for each substrate also contributed to consistency of the

experiment.

The waterproofing product was brushed on the four edges and the

uncut face of the slab. Coating the sixth side was omitted because this

would seal the test specimen and complicate interpretation of the results

The lightweight aggregate slabs were coated at a spreading rate of

2 2 2.45 m / 2,(100 ft /gal). Due to the lower porosity of the brick, the

higher solids materials were not absorbed as readily into the brick as

the lightweight block. Consequently, they dripped off when applied to

2 2 the brick slabs at a spreading rate of 2.45 m /I (100 ft /gal). Instead

2 2 4.90 m I % (200 ft / gal) was used for brick. These spreading rates were

chosen after examining the range of the manufacturers' recommended

spreading rates and are well within the range of recommendations listed

in Table 1. For example, of the fifty-five materials, twenty-four

25
had no label instructions for application on any substrate, seven had

2 2 higher than a 4.90 m /£ (200 ft /gal) spreading rate for brick, twelve

2 had lower rates of application, and twelve were close to 4.90 m /%> (200

ft

2 /gal).

The water absorption was measured on the lightweight aggregate

block slabs having one coat of waterproofing material. Results of this

72 hour test were disappointing. These results are tabulated in Table

2. Only three samples had water absorption averages as low as 40%, and

these were all high solids materials; they were No. 20, 33.6% urethane

resin; No. 40, 56.5% modified silicone resin; and No. 48, 53.0% silicone

resin. Some of the waterproofing products seemed to protect the block

slabs for about a day, but then permitted water to enter. Also, results

on the lightweight block slabs were inconsistent. Even among the more

successful samples, there were very few cases where the water absorption

of all 3 replicates was similar. With some products, the water absorption of one or two slabs was much lower than the remaining slab. These

initial results for coatings on lightweight concrete block gave little

differentiation between coatings. It was therefore decided to perform

water absorption tests on brick face slabs to seek a more definitive

ranking of the coatings. Later, the lightweight block slabs were given

a second coat of the waterproofing agent at the same spreading rate, and

water absorption measurements were repeated. As expected, the second

coat generally reduced water absorption appreciably; in one case, No. 12,

the change was from 89.3% to 9.2% (see Table 2).

The results of the water absorption tests run on brick face slabs

[one coat at 4.90 m

2

/ I (200 ft /gal)] are tabulated in Table 3. They

showed better differentiation between samples. Thirty-six samples out

of the total of fifty-five had average water absorption percentages of

40 percent or lower on brick as compared to only three for the coated

lightweight concrete block. Also, the materials which had 5 percent

silicone resin (Nos. 4, 13, 16, 19, 27, 28, 36 and 49) and which were

stated to, or would be expected to, conform to Fed. Spec. SS-W-110C

varied in percent water absorption from 6.8 to 96.4 (6.8, 8.3, 22.0,

25.7, 2 7.4, 54.2, 68.0, 96.4) and in ranking between seventh and fiftythird. From the water absorption results on both the brick and block

slabs, it was evident that there was a large variation in effectiveness

in protecting the substrate against water absorption. It should be

noted that the water absorption results on brick and lightweight block

with two coats ranked the waterproofing materials differently.

26
Table 3

Water Absorption, Water Vapor Transmission, and

Efflorescence Tests on Coated Brick Substrate*

Waterproofing Percent Percent Water Percent Water Vapor Efflorescence

Sample Solids Absorption** Transmission Rating***

24.4 4 81.9 3 45.3 4 25.3 4 39.3 2 23.9 2 38.0 4 18.4 4 45.5 4 27.8 3 29.2 4 21.5 3 28.8 4 17.7 4 58.3 2 18.7 4 14.5 3 31.8 2 36.1 4 16.1 3 76.7 4 29.2 2 55.0 2 37.5 4 52.2 3 34.8 3 27.3 3 68.0 3 9.1 4 24.8 4 25.8 3 20.2 2 45.8 3 57.7 4 47.7 3 78.6 4 55.9 2 19.6 4 28.8 4 8.3 4 51.6 3 74.7 1

58.1 2 48.8 3 46.3 4

1 27.2 67.0

2 18.5 100.3

3 4.7 19.6

4 3.7 25.7

5 35.9 91.1

6 19.9 22.8

7 13.2 63.9

8 21.2 7.5

9 4.8 50.7

10 6.8 7.1

11 33.5 68.2

12 6.2 6.5

13 4.6 27.4

14 33.1 66.3

15 17.7 71.7

16 5.1 22.0

17 39.7 11.2

18 30.3 29.2

19 4.3 68.0

20 33.6 10.3

21 10.1 95.8

22 4.9 6.0

23 15.5 36.4

24 5.6 15.9

25 25.8 48.3

26 9.0 73.4

27 4.6 8.3

28 1.4 96.4

29 78.1 13.4

30 37.0 12.3

31 16.4 7.6

32 30.8 6.1

33 6.6 9.4

34 8.0 31.2

35 12.1 30.2

36 3.4 54.2

37 20.8 93.7

38 31.1 9.9

39 18.2 5.0

40 56.5 8.6

41 10.0 45.0

42 26.1 41.6

43 17.7 13.1

44 18.1 13.3

45 49.3 17.6

2
Table 3 (continued)

Waterproof ing Percent Percent Water Percent Water Vapor Efflorescence

Sample Solids Ab sorption** Transmission Rat ing***

46 33.1 46.6 66.0 1 47 9.9 5.6 29.8 3 48 53.0 7.0 10.7 4

49 4.7 6.8 28.8 4 50 33.9 9.2 13.2 4 51 30.0 11.3 30.4 4

52 43.2 5.5 15.2 4 53 13.1 7.2 29.9 4 54 8.3 108.5 85.1 3

55 51.3 35.5 38.9 2 Untrea ted brick 83.4 1

Spreading Rate = 4.90 m 1 1 (200 ft /gal)

** The percent water absorption is the ratio of water absorbed by the

coated test specimen to the water absorbed by the test specimen before

it was coated.

*** 1 heavy efflorescence on coated surface

2 slight efflorescence on coated surface

3 no efflorescence on coated surface but salt residues on edges

4 no efflorescence on coated surface

28
In the course of the water absorption test, some random observations

were made. Waterproofing materials, 1, 29, 42, 46 and 55 turned white

where the material was exposed to water. The whiteness occurred even

after the samples had been aged one week before testing. It would not

have been expected that the resin would be affected by the presence of

water. Beads of white material were evident above the immersed areas on

the sides of No. 45, and No. 37 seemed to be flaking off in some of the

non-immersed areas. Even after the water absorption test, No. 48 was

not tack free.

3.2.2 Water Vapor Transmission

A waterproofing material applied to the exterior surface of a building should be permeable enough to permit transpiration of accumulated moisture to the outside. At the same time, the exterior surface

should be resistant to the inward passage of liquid water. Water vapor

transmission measurements were made on the coated brick slabs and the

averages of the three determinations are contained in Table 3. Fourteen

waterproofing materials had an average moisture loss of greater than

50%. The materials having 5% silicone resin had losses of 25.3, 28.8,

18.7, 36.1, 27.3, 68.0, 78.6 and 28.8 percent.

3.2.3 Resistance to Efflorescence

Results of the efflorescence tests are also tabulated in Table 3.

Only two materials permitted the formation of heavy efflorescence on the

coated surface while ten others developed slight efflorescence. On a number of test specimens, it seemed as if capillary action up the sides

had permitted some salts to accumulate on the sides at the upper edges,

although there was no evidence of efflorescence through the coated

surface. Figures 4 and 5 illustrate the observed differences in resistance to efflorescence. Of the twelve waterproofing materials that

permitted efflorescence to form, nine of the coatings contained acrylate,

styrene acrylate, or vinyl toluene acrylate resins, while two others had

aluminum stearate resins. All silicones and modified silicones resisted

the formation of efflorescence.

3.2.4- Appearance

Reflectance measurements were taken of the 55 waterproofing products

on brick, lightweight aggregate block and dense aggregate block. Changes

in the reflectance value caused by application of the waterproofing

materials are tabulated in Table 4. The visual effects of typical

coatings on dense and lightweight aggregate block are illustrated in

Figure 6. The horizontal strip across the middle of each block is an uncoated area for comparison. Often there is a noticeable change in

reflectance and also in gloss. Waterproofing materials 1, 5, 17, 18,

20, 29, 30, 32, 37, 38, 40, 42, 46, 51, 52 and 55 had a glossy appearance

on all three substrates. It is possible that where there are appreciable

differences in reflectance between original substrate and coated substrate, non-uniform application of a coating would produce an unsightly

result . There may be instances where differences in reflectance and in

29
Figure 4. Waterproofed Brick Samples from Efflorescence Test.

A - no evidence of efflorescence, rating 4.

B - no efflorescence on upper surface but accumulation

of salts on sides at upper edges, rating 3.

C - slight efflorescence on upper surface,

rating 2.

30
Figure 5. Brick Samples from Efflorescence Test.

D - waterproofed sample with heavy efflorescence,

rating 1.

E - uncoated brick with no waterproofing

applied, heavy ef f lorescnece, rating 1.

31
Table 4

The Effects of Waterproofing Materials on the Appearance

of Masonry*

Waterproofing Brick Lightweight Dense

Sample Aggregate Block Aggregate Block

1 5.9 8.9 24.9

2 2.4 2.5 6.6

3 2.1 5.5 2.6

4 1.5 3.4 .7

5 4.9 7.5 26.4

6 5.8 10.7 14.9

7 4.4 9.2 11.1

8 5.6 7.7 16.7

9 1.9 4.4 3.4

10 2.9 4.3 6.7

11 5.9 11.1 26.2

12 3.4 3.9 1.7

13 2.9 3.7 .2

14 5.6 9.6 24.7

15 .8 7.0 8.4

16 3.1 4.4 1.4

17 7.4 8.2 14.9

18 6.0 13.3 25.4

19 1.3 4.6 .7 20 6.6 11.9 16.9

21 2.9 5.1 12.9

22 2.8 4.7 13.1

23 3.4 15.8 11.4

24 2.2 5.0 8.2

25 3.2 7.5 17.9

26 4.2 3.4 6.9

27 3.3 1.0 8.6

28 3.0 .8 9.7

29 8.6 13.8 27.1

30 6.6 10.0 25.6

31 5.3 8.3 11.2

32 5.3 9.7 16.1

33 1.4 5.6 5.9

34 4.1 6.6 4.2

35 3.7 8.7 11.7

36 -3.4 -l.E .4 37 4.9 10.5 10.4

38 6.3 10.8 15.4

39 4.7 7.0 13.2

40 6.7 15.1 25.6

41 5.5 10.8 8.4

42 2.3 6.7 7.1

43 5.8 4.6 10.6

44 6.8 8.5 20.6

45 4.5 11.7 18.9

32'
Table 4 (continued)

Waterproofing Brick Lijjhtweight Dense

Sample Aggr<igate Block Aggregate Block

46 2.8 6.2 7.6

47 2.1 6.5 3.6

48 8.9 15.0 23.4

49 1.5 7.3 4.2

50 7.1 16.0 1.6

51 5.6 3.9 18.9

52 3.9 10.2 22.6

53 3.9 3.9 11.9

54 1.7 9.6 -.3

55 2.1 4.9 2.8

* The values in the table represent the differences between the 45°

reflectance of the specimens before and after waterproofing. Each

value represents an average of measurements taken in three locations

on the test specimens. The reflectance values for the untreated

masonry materials were: brick 19.5, lightweight aggregrate block 37.9,

dense aggregrate block 42.4.

33
Figure 6. Masonry units illustrating changes in appearance caused

by waterproofing materials Nos . 1-10. The upper unit is

a lightweight aggregate block while the lower unit is a dense aggregate block. The horizontal strip across the

middle of each block is an uncoated area for comparison.

34
gloss may not be too objectionable, but it would be recommended to coat

a small test area prior to coating any large surface area.

3.3 Second Phase Screening Tests

While the initial performance of any waterproofing material is

important, its ability to protect the substrate over an extended time

period is equally important. The waterproofing coating is expected to

protect the building and contents from water damage, and the coated

surfaces themselves should not introduce a potential maintenance problem.

The objective of the second phase was to measure durability characteristics

of selected coatings that showed good initial performance. The selection

of the fifteen waterproofing coatings for the second phase of the test was based primarily on the water absorption tests on brick, i.e., all were less than 20%. Consideration was also given to the inclusion of as many different generic types of waterproofing materials as possible.

For example, No. 3 was included because it was a water-thinned, modified

silicone.

Other factors involved in the selection were resistance to efflorescence, water vapor transmission, appearance, handling properties, and

solids content. For example, one sample was very caustic, one coating

had a limited pot life of approximately 30 minutes, and some samples

became whitish on exposure to moisture. All of these were excluded.

Some manufacturers produced several products by varying resin content

or solvent. In other cases, similar resins were used by more than one manufacturer as evidenced by similarity of the infrared spectra. The

resins of the following waterproofing materials were judged to be similar: Nos. 6, 7, 8, 33, 34, 35; Nos. 9, 10; Nos. 13, 48, 49; Nos. 20, 50;

Nos. 27, 40; Nos. 30, 38, 53; Nos. 31, 32; Nos. 43, 44. In such cases,

only one example of each resin type was included.

In general, the two-part systems and the water-thinned systems did

not perform well enough to be included in the second phase of the study.

Only the first fifty samples were considered for inclusion in the additional tests since the last five were received too late to complete their

initial screening prior to the start of the second phase. The fifteen

waterproofing materials selected are listed in Table 5.

The resin types contained in these fifteen consisted of five silicones

or modified silicones, two urethanes, two acrylates, one vinyl toluene

acrylate, one aluminum stearate and four resin mixtures. It should be

emphasized that each of these resins was distinct, although they may

have been of the same generic type.

Although there are many important durability characteristics in

materials, three tests, resistance to humidity, accelerated weathering,

and outdoor exposure, were chosen to evaluate the performance of the

fifteen coatings during the second phase of testing.

35
Table 5

15 Waterproofing Materials for the Second

Phase of Testing

Percent Water Absorption*

Waterproofing Resin Components Percent Lightweight Aggregate

Sample Solids Brick** Block**

3 silicone or modified 4.7 19.6 80.9

silicone

10 acrylate, aluminum 6.8 7.1 45.9

stearate, oil

12 silicone or modified 6.2 6.5 9.2

silicone, oil

17 urethane 39.7 11.2 27.9

20 urethane 33.6 10.3 28.1

22 aluminum stearate 4.9 6.0 93.2

24 silicone or modified 5.6 15.9 19.4

silicone, aluminum

stearate, oil

27 silicone or modified 4.6 8.3 32.6

silicone

31 acrylate 16.4 7.6 45.3

33 vinyl toluene acrylate 6.6 9.4 45.8

acrylate 16.4 7.6

vinyl toluene acrylate 6.6 9.4

acrylate 31.1 9.9

silicone or modified 18.2 5.0

38 acrylate 31.1 9.9 36.9

39 silicone or modified 18.2 5.0 33.4

silicone

43 styrene acrylate, chlori- 17.7 13.1 47.3

nated hydrocarbon

47 silicone or modified 9.9 5.6 41.2

silicone

49 silicone or modified 4.7 6.8 17.0

silicone

* The percent water absorption is the ratio of the water absorbed by the coated

test specimen to the water absorbed by the test specimen before it was coated.

** Brick slabs - one coat at 4.90 m^/l (200 ft 2 /gal)

Lightweight aggregate block slabs - 2 coats each at 2.45 rn^/t (100/ft /gal).

36
3.3.1 Resistance to Humidity

This test was intended to evaluate the effects of exposing the

coatings to 100% relative humidity with condensation on the coated

surface at all times. The results of exposure of coated brick slabs

in the Cyclic Environmental Tester are listed in Table 6. It is of

interest that for all but four samples the water absorption decreased

between the original values and the six week exposures. A possible

explanation is that there is some post cure of the resins which improved

their performance. By fourteen weeks exposure, Nos . 3, 33, 38 and 43

had appreciable increases in water absorption. No. 3 was a waterthinned product, while Nos. 33, 38 and 43 had vinyl toluene acrylate,

acrylate, and styrene acrylate mixture, respectively, as resins.

3.3.2 Resistance to Accelerated Weathering

The water absorption results after exposure of the coated brick

slabs in the Weather-Ometer for 500, 1000, 1500, 2000 and 2500 hours are tabulated in Table 7. The original water absorption values are listed

for comparison. Again, an apparent post-cure phenomenon occurred between

the original values and those at 500 hours exposure. As can be seen,

after 2500 hours, Nos. 17, 20, 22, 31, 33, 38 and 43 have had appreciable

increases in water absorption. In addition, Nos. 3, 10 and 39 have

risen slightly above the original values.

These results on the water absorption vs. exposure of the fifteen

samples are also illustrated in Figures 7 and 8. The purpose is threefold: to illustrate an apparent post-cure phenomenon, to show the similarities between silicone-containing waterproofing materials and to

point out the wider range of performance properties (water absorption)

of the other types of waterproofing materials. These figures also

illustrate the generally superior performance of the silicone-containing

waterproofing materials under these conditions. The products that

formed a film on the surface (Nos. 17, 20, 31, 38 and 43) were apparently

more affected by the ultraviolet radiation as evidenced by the greater

changes in water absorption. One high solids material, No. 39, was the

exception to this generality, but it also was a modified silicone and

would be expected to perform as the other silicone-containing waterproofing materials

.

When reflectance measurements were taken, a general slight fading

trend was noted, but the changes did not relate to water absorption

results.

37
Table 6

Water Absorption After Exposure to High

Humidity with Condensation*

Waterproofing Sample

Original

Percent Water Absorption**

6 Weeks 14 Weeks

3

10

12

17

20

22

24

27

31

33

38

39

43

47

49

19.6

7.1

6.5

11.2

10.3

6.0

15.9

8.3

7.6

9.4

9.9

5.0

13.1

5.6

6.8

29.7

4.3

2.4

5.1

4.6

4.7

4.1

2.9

5.2

30.1

9.2

6.3

57.6

3.7

2.6

39.6

1.7

.4

7.1

1.1

7.2

1.9

1.8

8.4

50.5

15.7

3.

2

67.4

3.4

1.6

* The test specimens consisted of brick slabs having one application of

waterproofing material at 4.90 m2 /£ (200 f

t

2 /gal)

.

** The percent water absorption is the ratio of the water absorbed by the

coated test specimen to the water absorbed by the test specimen before

it was coated.

38
Table 7

Water Absorption After Exposure in Weather-Ometer*

Waterproofing Percent Water Absorption**

Sample Original 500 h 1000 h 1500 h 2000 h 2500 h

3 19.6 11.6 13.6 16.7 14.6 20.3

10 7.1 3.5 10.7 10.9 13.2 11.0

12 6.5 5.7 9.7 5.4 6.0 4.8

17 11.2 5.8 12.0 21.4 41.1 62.3

20 10.3 6.3 11.1 17.7 11.2 17.5

22 6.0 6.2 59.1 54.5 53.7 66.7

24 15.9 3.8 8.4 6.6 4.8 4.7

27 8.3 5.8 9.0 5.8 4.9 4.1

31 7.6 7.4 43.1 23.8 20.6 51.0

33 9.4 32.8 93.5 104.9 98.6 100.2

38 9.9 4.4 9.9 7.4 10.2 18.5

39 5.0 5.4 11.3 10.5 8.6 9.9

43 13.1 17.0 86.7 90.7 68.5 101.1

47 5.6 4.3 7.3 7.4 7.0 6.7

49 6.8 4.0 6.5 7,6 4.5 5.2

* The test specimens consisted of brick slabs having one application of

waterproofing material at 4.90 m^/£ (200 f t^/gal)

.

** The percent water absorption is the ratio of the water absorbed by

the coated test specimen to the water absorbed by the test specimen

before it was coated.

39
Figure 7 - Accelerated Weathering Exposure of Waterproofing

Materials Containing No Silicone Resins

100 i

KEY

10 - ACRYLATE,

ALUMINUM

STEARATE.OIL

17- URETHANE

20- URETHANE

22- ALUMINUM

STEARATE

31- ACRYLATE

33- VINYL TOLUENE

ACRYLATE

38- ACRYLATE

43- STYRENE

ACRYLATE,

CHLORINATED

HYDROCARBON

500 1000 1500 2000 2500

HOURS OF EXPOSURE

These are the materials from the second phase of testing which contain

no silicone resins. (The products with silicone resins are in figure

8.) The test specimens were brick slabs with one coat of waterproofing

material applied at 4.90 m2/£ (200 f

t

2 /gal)

.

40
Figure 8 - Accelerated Weathering Exposure of Waterproofing

Materials Containing Silicone Resins

lOO-i

90-

80-

70-

p 60 H

Q.

0COif) CO^0- <ruj

i-i

^ 40-

UJo

oc

us

Q. 30-1

KEY

3 - SILICONE OR MODIFIED SILICONE I2-SILIC0NE OR MODIFIED SILICONE 24- SILICONE OR MODIFIED SILICONE,

ALUMINUM STEARATE.OIL

27- SILICONE OR MODIFIED SILICONE 39- SILICONE OR MODIFIED SILICONE 47- SILICONE OR MODIFIED SILICONE

49- SILICONE OR MODIFIED SILICONE

500 1000 1500 2000

HOURS OF EXPOSURE

2500

These are the materials from the second phase of testing which contain silicone

or modified silicone resins. (The products with no silicone are in figure 7.)

The test specimens were brick slabs with one coat of waterproofing material

applied at 4.90 m2 /l (200 f t2/gal)

.

41
3.3.3 Outdoor Exposure

The 72 hour water absorption was measured on the specimens which

had been exposed to natural weathering for six months. These results

are contained in Table 8. Similar trends were also observed during the

six hour water absorption tests which were performed at one month intervals

to monitor changes in the materials. Waterproofing materials Nos. 17,

20, 22, 33, 38 and 43 all showed appreciable increases in water absorption from the original values. Although the water absorption of No. 3

did not rise above the original, it was high when compared to the other

products. Reflectance measurements were taken, but as with the accelerated weathering exposures, only a general slight fading trend was noted.

Uncoated brick also changed slightly in 5 months exposure.

The outdoor and Weather-Ometer exposures compare favorably. The

fact that there was a good correlation between outdoor and WeatherOmeter exposures justifies the inclusion of an accelerated aging test in

the performance criteria for these clear waterproofing coatings.

3.4 Mortar Joint Evaluations

The purpose of these tests was to evaluate the effectiveness of

different types of products in waterproofing mortar joints.

3.4.1 Resistance to Wind-Driven Rain

This test was a laboratory simulation of wind-driven rain which is one of the main causes of above grade water infiltration into buildings.

Since the wind-driven rain test is severe, dense aggregate block slabs

rather than lightweight aggregate block slabs were chosen as the substrate

for preliminary tests. The slabs were coated with three waterproofing

materials (Nos. 10, 31 and 49) which were chosen to have a variation in

solids content and resin type. No. 10 was an acrylate, aluminum stearate,

oil mixture of 6.8% solids, while No. 31 was an acrylate having a relatively high solids content of 16.4%. No. 49 was a 4.7% silicone conforming to SS-W-110B and was useful for comparison.

The resistance to wind-driven rain of all the test specimens which

2 2 had a single coat of waterproofing material at 4.90 m /l (200 ft /gal) was poor, i.e., pinhole leaks were observed within 15 minutes and,

within an hour, 1/4 to 1/2 of the back surface was wet. Application of

2 2 a second coat at 4.90 m /I (200 ft /gal), improved the resistance to

wind-driven rain, but water still penetrated to the back surface of all

the specimens after five hours.

After the preliminary tests on dense aggregate block slabs were

completed, brick wallettes were coated with three waterproofing materials.

These three materials used in the evaluation on the mortar joints were

42
Table 8

Water Absorption After Exposure Outdoors*

Waterproofing Percent Water Absorption**

Sample Original 6 months

3 19.6 17.1

10 7.1 6.5

12 6.5 4.6

17 11.2 53.3

20 10.3 49.6

22 6.0 11.8

24 15.9 3.9

27 8.3 4.1

31 7.6 8.6

33 9.4 99.8

38 9.9 17.4

39 5.0 6.1

43 13.1 98.9

47 5.6 4.7

49 6.8 5.8

* The test specimens consisted of brick slabs having one application

of waterproofing material at 4.90 m2/£ (200 f t2/gal) . They were

exposed from May to November 1974 at the NBS exposure site in

Gaithersburg, Maryland.

** The percent water absorption is the ratio of the water absorbed

by the test specimen before it was coated.

43
selected on the basis of their good performance after 1500 hours in the

Weather -Ometer and represented a range in solids content and resin type.

Availability of the quantity needed for the applications was also a factor. The waterproofing materials used were: No. 27, a 4.6% silicone;

No. 38, a 31.1% acrylate; and No. 47, a 9.9% modified silicone.

Due to the irregular surface at the joints, the wallettes could not

be sealed successfully on the wind-driven rain apparatus. Since this

testing involved determining the protection a waterproofing material

affords at the brick-mortar interface, the wind-driven rain test was considered impractical for this purpose.

3.4.2 Exposure to Hydrostatic Pressure

This test was set up as an alternative to the wind-driven rain

test. It was designed to measure the water permeability of a coating

exposed to water at a pressure of 1245.5 Pascals or 12.7 cm (5 in) of

water which is equivalent to a wind of 160.9 km/h (100 mph) [21], as in

the wind-driven rain test. It was more convenient than the wind-driven

rain test because the specimens were tested in a horizontal position and

could be more easily sealed to the test apparatus, and because the

specimens could be tested individually rather than in groups of three.

The loss of water with time and the visual examination of the

mortar joints were used to judge the effectiveness of the waterproofing

materials. Visual examination of the mortar joints showed that water

leakage occurred through about half of the joints. After 3 days, few of

the wallettes had any water remaining in the tank. All wallettes coated

with No. 27 permitted all of the water to pass through. One of the test

specimens coated with No. 38 had water remaining, while four of the

wallettes coated with No. 47 retained some water.

When this test was completed on the wallettes having one coat of

waterproofing material, half of the wallettes were dried and an additional

2 2 coat at 2.45 m /£ (100 ft /gal) was applied. After a one week cure

period, the test was repeated. Although there was improvement with the

addition of the third coat of waterproofing material, some water did

penetrate all wallettes even after only six hours. After 24 hours

exposure, wallettes coated with No. 27 had 2.5 cm (1 in), 8 cm (3 1/8

in), and 10 cm (4 in) of water remaining; wallettes coated with No. 38

had 8.3 cm (3 1/4 in), 11 cm (4 1/4 in), and 12.7 cm (5 in) of water

remaining; and wallettes coated with No. 47 had 7.6 cm (3 in), 11 cm (4

1/4 in), and 12.7 cm (5 in) of water remaining. It appears that well44
filled mortar joints can be waterproofed if a sufficient quantity of a good waterproofing material is applied. However, it must be pointed out

that the sealing of the surface may result in a low water vapor transmission

which could introduce new problems. This might include the concentration

of soluble salts in the walls which may crystallize underneath the

surface treated with the waterproofing material and cause the masonry

surface to spall off.

The use of this test did not answer the question of how to test

mortar joints when evaluating a coating. The 12.7 cm (5 in) head of

water is equivalent to about a 160 km/h (100 mph) wind and is too extreme.

In areas that are subjected to hurricane force winds, sealing the joints

to these pressures is imperative. However, in other regions it should

not be necessary. Modifying this test to use hydrostatic pressures

which correlate with more normal wind velocities could make it useful in

evaluating the resistance of coatings to wind-driven rain.

3.5 Methods of Application

These tests were carried out to determine the relative effectiveness of four different methods of application of waterproofing agents to

masonry surfaces. The methods used were brush, roller, conventional air

spray and airless spray. Two waterproofing materials were used, they were No. 6, 19.9% solids and No. 24, 5.6% solids. They were selected

because of their different solids content. The application rate was not

specified, rather the waterproofing materials were applied until the

surface was saturated or flooded. Two coats were applied 24 hours

apart. After a one week cure the waterproofing effectiveness was judged

by submitting brick slabs and lightweight aggregate concrete slabs to a 72 hour water absorption test. These test results are listed in Table

9. In general, brush and roller were more effective than spray application.

'45
Table 9

Water Absorption on Masonry Substrates Having Waterproofing

Materials Applied by Different Application Procedures*

Percent Water Absorption**

No. 6, 20% solids No. 24, 6% solids

Application Brick Lightweight Aggregate Brick Lightweight Aggregate

Method Concrete Block Concrete Block

Brush 7.0

Roll 5.1

Airless

Spray5 """ 53.3

Air Spray*** 18.8

34.8

42.8

42.2

79.8

4.7

5.9

12.5

30.4

11.2

14.0

67.7

81.4

Two flood coats of waterproofing material were applied 24 hours

apart.

The percent water absorption is the ratio of the water absorbed by

the coated test specimen to the water absorbed by the test specimen

before it was coated.

Cobwebbing (a spider web effect caused by premature drying) was encountered with the 20% solids material.

4. FIELD SURVEY

A number of maintenance officials in HUD area and regional offices

were surveyed with respect to their experiences in the field application

and performance of waterproofing treatments. Several points were

evident from these discussions which are reported in Appendix A. Apparently, the eastern and southeastern areas of the United States have

more serious waterproofing problems than other regions. Since some water may enter through paths other than through the walls, the cause of

water infiltration should always be determined prior to waterproofing.

Most successful waterproofing treatments involve the application of more

than one coat of material. Best results seem to be attained by hiring

an experienced commercial firm for the application of the waterproofing

material, and requiring a guarantee of their work.

46
5. RECOMMENDATIONS FOR THE SELECTION AND APPLICATION OF CLEAR WATERPROOFING MATERIALS FOR MASONRY

Based on the literature, the test results reported here, and the

field experiences of HUD area and regional engineers, the following

recommendations concerning the selection and application of clear

waterproofing materials for masonry may be made:

1. The cause of the water infiltration problem should be

determined. The building should be inspected to identify

repairs or improvements which may be necessary before applying

a waterproofing material.

2. Prior to application of any waterproofing product, all

mortar joints should be sealed, and, unless a manufacturer

specifically guarantees that his material will bridge such

imperfections, cracks greater than 0.05 cm (0.02 in) in either

the joints or the masonry units should be filled.

3. If it is impractical to repoint or fill large cracks, the use of surface fillers and pigmented coatings should be con- sidered.

4. Waterproofing materials which meet the performance

criteria given in Appendix C should be used. In general,

solvent-based materials are more likely to meet the criteria

than two-part materials or water-thinned products.

5. The surface should be prepared in accord with the manufacturer's recommendations. The surface on which the waterproofing material is to be applied should be clean and dry.

Dirt, grease, asphalt, stains, efflorescence, or other loose

material should be removed from the surfaces by approved

methods prior to application of the waterproofing material.

6. The method of application should be in accord with the

manufacturer's recommendations. Laboratory tests found that

brush and roller application usually give better results than

spray application, with the airless spray being more effective

than air spray. However, in the field, airless spray has been

found to be a very effective method of application.

7. A minimum of two coats of the waterproofing product

should be applied at spreading rates recommended by the

manufacturer for the specific substrate and method of application.

8. Where appearance is critical, a test panel should be

coated prior to general application of any coating to determine if the appearance of the coated material is acceptable to

the buyer.

47
9. The weather conditions on the day of application should

fall into the range recommended by the manufacturer.

10. Where possible, waterproofing should be done by a com- mercial firm whose specialty is waterproofing and who is

willing to bond or guarantee the work. In any case, experienced personnel should do the work and, if possible, a manufacturer's representative should be present during the application.

6. SUMMARY AND CONCLUSIONS

The fifty-five waterproofing materials obtained for the study were representative of those produced for waterproofing in above ground

application. The resins used for these materials were identified by

infrared analysis and included the following generic types: silicones or modified silicones; acrylates ; styrene acrylates, vinyl toluene acrylates;

urethanes; aluminum stearate mixtures; silicone and other resin mixtures;

polyesters; inorganic; as well as various resin combinations.

A screening process, based upon initial performance of the coatings

on masonry substrates, was used to limit the number of waterproofing

materials to fifteen for the second phase of the testing. The tests

included water absorption, water vapor transmission, resistance to

efflorescence, appearance and handling properties. The second phase

screening was designed to evaluate the durability characteristics of the

fifteen coatings that showed good initial performance. The durability

tests performed were: resistance to humidity, accelerated weathering and

outdoor exposure.

These performance tests were used to develop recommended performance

criteria for the selection of clear waterproofing materials for use on masonry surfaces. The criteria are listed in Appendix C. Table 10

tabulates the results of the screening tests related to the performance

criteria for the fifteen waterproofing materials.

The ability of a waterproofing material to protect the substrate

over an extended period of time is most important. Consequently, the

results of the Weather-Ometer and outdoor exposures are especially

significant. After 2500 hours in the Weather-Ometer and six months

exterior exposure, sample Nos. 10, 12, 24, 27, 39, 47 and 49 have continued to show good performance. No. 39 is no longer available in this

country, although it performed well in these tests. It may be noted

that, of the materials that met all the performance criteria, most

materials contained silicone resins, but only two were analogous to the

silicone water repellent as described in Fed. Spec. SS-W-110C. Also, of

the waterproofing materials used in this study, twenty-one contained

silicone resins. This indicates that the presence of silicone resins is

not always a guarantee of good waterproofing performance.

48
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While the second phase of this study was limited to testing fifteen

materials, other products contained similar resins (see Section 3.3).

Although Nos. 9, 13, 40 and 48 were not tested, they have resins similar

to some of the waterproofing materials mentioned above that have shown

good performance. Similar performance may be expected from these,

provided that the percent solids content is at least equal to the waterproofing material above having an equivalent resin. It should be noted

that Nos. 40 and 48 are intended to be diluted rather than used at the

concentration provided for this study.

The final testing included the performance characteristics of

selected waterproofing materials on exposure to laboratory simulation

of wind-driven rain of 160.9 km/h (100 mph) . Although two and three

coat applications of waterproofing materials were applied, some of the

mortar joints in the brick wallettes continued to leak. Modification of

the test, exposing the test specimens to hydrostatic pressure to more

closely relate it to normal wind velocities, could make this a more useful test for the evaluation of coatings to wind-driven rain.

On the basis of the tests performed, it appeared that the WeatherOmeter results, which related closely to the results of outdoor exposure

at the NBS site can predict failures of the waterproofing materials.

However, this test uses single unit test specimens, e.g. a single brick

slab, while the major waterproofing problem is involved with the overall

masonry system. This system includes cracks and voids in the masonry

substrate, open cracks between mortar and masonry due to loss of bond,

incompletely filled mortar joints, settlement cracks, and the porosity

of the particular materials. The results of tests performed to measure

the ability of certain materials to waterproof mortar joints were

inconclusive. More work should be done on the development of suitable

methods to evaluate water penetration. In addition to modification of

existing tests, another approach to investigating the properties of

waterproofing agents could be through a study of the effects of waterproofing materials on material properties pertaining to liquid penetration. This could include measurement of contact angles, breakthrough

pressures, and pore size distribution. Such an approach is outlined in

Appendix D. Characterization of performance in this manner could be the

starting point to development of test methods of a more basic and general

type.

The methods of application of waterproofing materials were studied.

A list of recommended practices for application was prepared based upon

literature survey, the test results reported, and the survey of field

application and performance experience of HUD area and regional maintenance officials.

50
7. ACKNOWLEDGMENTS

This investigation was supported by the Department of Housing and

Urban Development (HUD). The authors wish to thank George Erickson,

HUD, for his helpful advice, encouragement, and assistance in obtaining

waterproofing materials. We wish to also thank the following people for

their guidance and assistance: Thomas Redmond, National Concrete Masonry

Association, who provided the concrete masonry block; James Gross, NBS,

who aided in selecting the brick; Mildred Post, NBS, for providing the

infrared analyses; Jessie Hairston, NBS, who prepared the brick and block

test specimens and assisted in the screening tests; and Louis Cattaneo,

NBS, who furnished the data on the physical properties of the brick used.

51
8. REFERENCES

[I] Maslow, P. , Waterproofing, Chapter 8, Chemical Materials for

Construction, pp. 433-471 (Structures Publishing Company, Farmington,

Michigan, 1974).

[2] Decorative Waterproofing of Concrete Masonry Walls, NCMA TEK 10, A

Manual of Facts on Concrete Masonry, (National Concrete Masonry

Association, Arlington, Virginia, 1968).

[3] Kessler, D. W. , Exposure Tests on Colorless Waterproofing Materials,

Technologic Papers of the Bureau of Standards, 18, No. 248, 1-33

(Jan. 1924).

[4] Jumper, C. H. , Tests of Integral and Surface Waterproof ings for

Concrete, J. Res. Nat. Bur. Stand. (U.S.) ]_, 1147-1177 (1931).

[5] Fishburn, C. C, Watstein, D., and Parsons, D. E., Effect of Outdoor Exposure on the Water Permeability of Masonry Walls, Nat. Bur.

Stand. (U.S.), Building Materials and Structures Report 76, 21

pages (Aug. 1941).

[6] Anderegg, F. 0., Testing Surface Waterproofers, ASTM Bulletin, pp.

71-77 (Jan. 1949).

[7] Litvin, A., Clear Coatings for Exposed Architectural Concrete, J.

of the Portland Cement Association Research and Development Laboratories, pp. 49-57 (May 1968).

[8] Kanarowski, S. M., Waterproofing Materials for Prevention of Windblown Rain Penetration through Masonry Walls, Technical Report M75, April 1975 (Construction Engineering Research Laboratory, P. 0.

Box 4005, Champaign, Illinois 61820).

[9] Kruger , J. E. and Loubser, P. J., Water Penetration of Buildings,

The South African Builder, 44, 8 (1966).

[10] General Services Administration, Federal Specification SS-W-110C,

Water Repellent, Odorless, Silicone Base, 5 pages (June, 1972).

[II] General Services Administration Federal Specification TT-C-555B,

Coating, Textured (For Interior and Exterior Masonry Surfaces), 8

pages (Feb. 1973)

.

[12] Volatile and Nonvolatile Content, Method 4041.1, Fed. Test Method

Std. No. 141a, Paint, Varnish, Lacquer and Related Materials;

Methods of Inspection, Sampling, and Testing, Superintendent of

Documents, U. S. Government Printing Office, Washington, D.C. 20402

(1965).

j2
[13] Infrared Spectroscopy, Its Use in the Coatings Industry, Chicago

Society for Paint Technology, (Federation of Societies for Paint

Technology, Philadelphia, Pa., 1969).

[14] Concrete Masonry Units, Sampling and Testing, C 140-70, ASTM Book

of Standards, Pt . 16, (American Society for Testing and Materials,

Philadelphia, Pa., 1974).

[15] Brick and Structural Clay Tile, Sampling and Testing, C 67-73, ASTM

Book of Standards, Pt. 16, (American Society for Testing and

Materials, Philadelphia, Pa., 1974).

[16] 45-Degree, O-Degree Directional Reflectance, Method 6121, Fed. Test

Method Std. No. 141a, Paint, Varnish, Lacquer and Related Materials;

Methods of Inspection, Sampling, and Testing, Superintendent of

Documents, U. S. Government Printing Office, Washington, D.C. 20402

(1965).

[17] Specifications for Mortar for Unit Masonry, C 270-73, ASTM Book of

Standards, Part 16, (American Society for Testing and Materials,

Philadelphia, Pa., 1974).

[18] Smith, L. M. , Water Permeability Tests on Concrete Masonry Units,

New Zealand Concrete Construction, 9_, 4, 72-4 (April 1965).

[19] General Services Administration, Federal Specification TT-C-00598C,

Caulking Compound, Oil and Resin Base Type (for Building Construction),

13 pages (June 1970)

.

[20] Paint Operations, Chapter 4, Paint and Protective Coatings Manual,

Army TM-5-618, NAFAC Mo-110, Air Force AFM 85-3, (Superintendent of

Documents, U. S. Government Printing Office, Washington, D.C.

20402, 1969).

[21] Infiltration and Natural Ventilation, Chapter 19, ASHRAE Handbook

of Fundamentals, pp. 33-346, (American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., New York, New York,

1972).

53
APPENDIX A

FIELD SURVEY OF APPLICATION AND PERFORMANCE

OF WATERPROOFING MATERIALS

Al . Background

HUD maintenance engineers in seventeen regional and area offices

throughout the country were contacted to obtain information about maintenance and application problems encountered in the field. The information gathered is summarized in this Appendix. A survey form similar

to the one in Appendix B could be used in establishing a data bank which,

if coordinated with HUD headquarters, could serve as a record of performance and provide data on durability.

A2. Geographical

Some HUD personnel listed water infiltration as a major continuing

maintenance problem, while others had difficulty in recalling more than

one or two specific instances. In general, it appears that is a more

serious problem in the east and southeast than in other regions of the

country. Some areas reported dampness on the interior of a building but

this was due to condensation in areas of high relative humidity rather

than from water leaks from the outside.

A3. Major Problem Areas

Waterproofing problems appear to occur primarily above grade in

both low and high rise apartment buildings. Waterproofing below grade was not considered to be a large problem.

The problems mentioned fell into several categories. A number

related to the original construction of the building. These ranged from

design deficiencies to problems resulting from poor workmanship. An

example of design deficiency is cracks caused by normal building movements as in a large prestressed concrete building erected with no expansion joints to allow for thermal movement. In this case, water infiltration is difficult to halt because, if the cracks are patched, subsequent

movements of the structure may cause the cracks to reopen or cause new

cracks to occur. A similar deficiency exists when expansion joints are omitted from large concrete slabs intended for floors and roofs. Movement of the concrete may cause cracks to form in the exterior mortar

joints. Another example is a structure in which the loads on exterior

brick walls which support the floors cause cracking in the walls.

Contrary to expectation, hollow core walls were cited by several as being more prone to water infiltration than the older type of solid

brick or masonry construction. Sometimes there was concern that the

walls might not have been constructed properly. In such cases, it was

54
considered wise to consult an architect with specific experience with

the type of construction involved. Application of a waterproofing

material may not solve the problem.

Other leakage problems cited were related to water entering through

roofs or in the area of existing openings such as doors and windows.

These problems can usually be eliminated by proper roof flashing or careful application of a good caulking around the doors and windows.

It does not seem that waterproofing problems are confined to buildings of any particular age. Some officials mentioned that their waterproofing problems were primarily limited to buildings twenty or more

years old, while others had major concerns with structures less than

five years old.

A4. Materials

The type of building material which seemed to be most frequently

involved in problem areas was brick. However, prestressed concrete,

cinder block, concrete block, split block and stucco were also mentioned,

This may reflect the frequency of use of these particular materials in

the areas having waterproofing problems. In addition, mortar joints

were almost universally cited as a contributing problem if not the major

one. Joints in the end walls were cited several times as having waterproofing problems.

There are several reasons for water infiltration. Some of the

materials are naturally more porous than others. Certain materials

deteriorate with age and weathering and become more porous, e.g. limesand mortar. In addition, cracks may form and permit the passage of

water through the material. Also, deterioration with age may cause looseness of joints or damage to building materials. Extreme conditions

such as high winds or hurricanes, or abrasion by wind-driven sand, may

accelerate changes in the surface of the material.

A5 . Treatments

Several solutions to problems caused by cracks were mentioned.

With mortar joints, depending on the size of the crack, the mortar may

be tuck-pointed. Others merely repair with new mortar or caulking. In

certain cases of hairline cracks, a waterproofing material is applied

directly to the surface. This should only be done if the manufacturer

says the material can bridge cracks of the size present and can provide

evidence of its ability to do so. Otherwise cracks should be repaired

first.

Since it is often difficult to identify the specific joints that

leak in a wall, it is generally necessary to repair all joints on the

entire wall or in the particular area. Although it cannot be used with

clear waterproofing products, one novel solution to joint crack problems

was reported. It involves painting the joint or crack then immediately

55
placing a 9 cm (3 1/2 in) wide fiber glass strip in the wet paint over

the joint. Later, another coat of paint is applied over the entire

wall. This solution is reported to cost less than half the cost of

replacing the mortar and has continued to be effective for more than 5

years. However, this treatment involves the use of pigmented coatings

and would not be used with clear waterproofing materials. Nevertheless,

some find the use of color coatings makes the buildings more attractive

and provides individuality to buildings in large projects.

A6. Selection of Waterproofing Materials

Once a waterproofing problem has been found, the choice of waterproofing material is important. Most officials related unhappy experiences with materials which were totally inadequate. Those with serious

waterproofing problems agreed that finding a waterproofing product which

would last more than a couple years was difficult. As a result, when

they found a process or product which filled their needs, they used it

exclusively.

A7 . Service Life

Service life with waterproofing materials varied. Silicones have

long been known as waterproofing products, yet many reported they were

able to get only 2 to 3 years of service from one coat of silicone.

Consequently, they switched to other materials which provided a longer

service life. Due to high labor costs, most officials prefer as few

coats as possible and would put on one heavy coat rather than two thinner coats. Some individuals were satisfied with silicone performance

and reported five years and more of service. It was pointed out that a 5% silicone should not be thinned (as is often done on site by applicators), that two or more coats are necessary, and that warm temperatures

during application are important. Failure to follow this advice could

shorten the life expectancy for silicone materials.

A8. Application

Many who had gone to products other than silicone carefully described

the application procedure. Usually, it consisted of careful surface

preparation followed by a multiple coat application of the waterproofing

material under closely supervised conditions. It was pointed out that

waterproofing integrity was best assured when temperatures of 10°C

(50°F) or above are observed during application. In addition, all

waterproofing materials should be manually stirred before and during

application.

In most cases waterproofing jobs were contracted out to commercial

firms with specialized experience. When possible, a guarantee for

minimum expected performance was obtained. While the ultimate in waterproofing is permanent protection, a service life of at least 10 years is

desirable. When HUD maintenance personnel applied the waterproofing

materials, generally they were either experienced or had a manufacturer's

56
representative present to advise. In any case, for optimum results, it was felt that the manufacturer's recommendations must be followed strictly

and, if possible, a manufacturer's representative should be present

during the application. When possible, waterproofing should be accomplished

by a recognized, local, firm that guarantees and certifies its work.

Only minor problems involving incompatibility of new and old waterproofing products have been encountered. One way to handle this is to

delay application by permitting the existing product to weather off. If

time does not permit this, a pressurized detergent wash followed by high

pressure water (3.45 MPa (500 psi)) has been effective in removing

coatings from masonry. With certain products, it may not be possible to

get good adhesion on any building material that has been previously

coated. These could be applied to new construction only.

Conventional air spray seemed to be the most common application

method utilized with waterproof ers. Brushes were also frequently

employed, depending on the substrate, but this was a more labor intensive application method. Airless spray and roller application were used

far less often. Fertilizer spray pumps for small jobs are efficient and

have been quite productive. On two story buildings, telescopic poles

have been used to apply materials.

A9 . Summary

The comments from the HUD maintenance engineers emphasized several

important points. These were:

1. Certain parts of the United States, particularly the east

and southeast, tended to have more serious and frequent water

infiltration problems.

2. Application of a waterproofing material did not solve all

water infiltration problems. The building should first be

inspected to determine the cause of the problem. Certain

repairs or modifications may be needed before applying a waterproofing material. Poor design of a building may permit

water leakage which cannot be corrected with conventional

waterproofing products.

3. Successful waterproofing procedures usually involved

careful surface preparation followed by the application of

several coats of material. Problems with silicones may have

been due to lack of care in surface preparation.

4. Commercial firms which guaranteed their work usually gave

good results.

57
APPENDIX B

PROPOSED WATERPROOFING SURVEY FOR CLEAR WATERPROOFING AGENTS

Name

Title

Number of units

responsible for

1. What type of waterproofing problems do you have?

Above grade Below grade

2. What are the results of waterproofing problems, e.g. interior

damage?

3. In what type of construction do you have problems?

High rise Single family detached

Low rise Single family attached

4. What type of building materials are leaking?

Wood Concrete

Stone Cinder block: dense porous

Brick Mortar joints

Other

5. Are the leaks localized in one wall or at one level?

6. What direction do the leaking walls face?

58
7. Does the water enter only under certain weather conditions or at

certain times of the year?

8. Do you have problems with cracks? How big?

9. Do you know their cause?

10. What products have you used to waterproof?

Brand Name Others

11. Are these clear?

12. How did you choose these products?

13. What are the most effective clear products?

Brand Names

14. What are the least effective clear products?

Brand Names

15. Do you use different waterproofers on different substrates?

16. How often do you have to repeat the treatment? yrs,

17. What problems do you encounter in waterproofing application?

59
18. Problems of compatibility of different products?

19. Is the wall prepared in any way before application of the

waterproofing material?

20. What method of application is used:

Air spray Brush Other

Airless spray Roller

21. How many coats? How long between coats?

22. Do you observe any special precautions during application?

23. Do you use different application methods with different products?

24. Do you have any special application techniques which you use or

know of?

25. Is your waterproofing done by your own maintenance crews or by

employees of a commercial waterproofing company?

60

,
26. Do you require a guarantee?

If so, what does it include?

27. How much money do you spend on waterproofing (cost/year)?

Labor Materials Labor & Materials

61
APPENDIX C

RECOMMENDED TENTATIVE PERFORMANCE CRITERIA FOR THE SELECTION

OF CLEAR WATERPROOFING MATERIALS FOR USE ON MASONRY SURFACES

CI. Introduction

Tentative performance criteria for the selection of clear waterproofing materials for use on masonry surfaces have been developed.

These criteria are based on results of tests conducted on fifty-five

clear waterproofing materials. The tests and criteria are intended to

be used in evaluating the performance of clear waterproofing materials

and they may be more severe than real life situations. The criteria

selected were chosen to reflect performance characteristics which these

waterproofing materials would be expected to show in service; they

include appearance, application, water repellence, water vapor transmission,

resistance to efflorescence, and resistance to accelerated weathering.

A description of the substrate materials, test methods, and conditions of application are included along with the performance criteria in

this Appendix since some people may choose to use these as guidelines

for purchase specifications.

The brick used in the development of these criteria were commercially

available good quality brick for building construction. Since the brick

to be used was cored, face slabs approximately 6 cm x 19 cm x 3 cm

(2 1/4 in x 7 1/2 in x 1 1/4 in) were cut for test specimens. Due to

the variation in water absorption of individual brick slabs, separate

water absorption determinations for each test specimen before coating were necessary. The brick slabs had an average water absorption after

24 hour submersion of 7.1% based on the dry weight of the brick. However, individual slabs were found to vary between 5.7 and 10.2 percent.

These criteria were developed using a one coat application of

waterproofing material on brick face slabs at a spreading rate of 4.90

2 2 m 1 1 (200 ft /gal). The four edges and the uncut face of the test

specimen were coated with waterproofing material for the tests. This

spreading rate was chosen after examining the range of the manufacturers'

recommended spreading rates. It should be noted that this spreading

rate was intended for testing purposes and should not be interpreted as

a recommendation for a spreading rate for field applications.

These criteria may also be applied when examining waterproofing

materials according to the individual manufacturer's recommended rates

of application. Manufacturer's recommendations vary in spreading rate

for different masonry substrates, as well as in the number of coats to

be applied. If either the rate of application, the number of coats or

the substrate materials differ from those used in the development of

62
these criteria, the criteria may not be directly applicable. In such a case, the performance criteria would have to be modified in certain

performance tests. Any variances in the performance requirements should

be agreed upon between purchaser and the manufacturer. This should

include agreement on the rate of application for testing (including

number of coats) and the method of application as well as the substrate

material. The designated rate, method and substrate should then be used

in all tests.

To permit all waterproofing materials to cure equally before being

tested, all test specimens were cured for one week at normal laboratory

conditions (about 25°C and 35% relative humidity) after coating.

C2. Performance Criteria

C2.1 Effect on Appearance of Masonry Surfaces

Requirement

When applied using the designated rate and method to the clean,

dry, masonry surface to be waterproofed, the material should present a uniform appearance and should not change the reflectance of the substrate

appreciably.

Criterion

When applied using the designated rate and method, the reflectance

of the coated masonry should not differ by more than 10 units from that

of the uncoated masonry substrate when examined by directional reflectance

measurements as described in Fed. Test Method Std. No. 141a, Method 6121

[1] . The uncoated masonry substrate should have a directional reflectance

of at least 35.

Commentary

Materials with a resin content higher than 35 percent tended to

form a noticeable glossy film on the surface. While the reflectance

requirement is included to ensure that the original appearance of the

masonry substrate is maintained, there may be instances where agreement

between purchaser and supplier may eliminate this requirement, e.g., the

masonry substrate is dark and reflectance differences would be minimal,

or the darker appearance, if uniform, may be esthetically acceptable.

[1] 45-Degree, 0-Degree Directional Reflectance, Method 6121, Fed. Test

Method Std. No. 141a, Paint, Varnish, Lacquer and Related Materials;

Methods of Inspection, Sampling, and Testing, Superintendent of Documents,

U. S. Government Printing Office, Washington, D.C. 20402 (1965).

63
C2.2 Application Properties

Requirement

The waterproofing material should have good flow, leveling, and

spreading characteristics. The coating should be capable of being

applied by the designated method. The coated surface should be capable

of being recoated within 24 hours.

Criteria

The waterproofing material when applied using the designated rate

and method, should dry to a uniform, smooth appearance with no conspicuous

laps or film on the surface, and no brush, spray, or other similar

characteristic marks.

Commentary

A clear waterproofing material is designed for use where the

original appearance of the masonry is to be retained. Conspicuous laps

or film of waterproofing material on the surface will change the uniformity of appearance. Where more than a one coat application is

desired, it is necessary that the coating be absorbed into the surface

readily. This was a problem with some of the water-thinned materials,

making it extremely difficult to apply a uniform second coat. While the

manufacturer is given wide latitude in the manufacture of the waterproofing material, it should be noted that the two-package catalyzed systems

or aqueous resin dispersions were generally found to be unsuitable

because of limited pot life, gloss imparted to the surface, or the

assumption of a whitish opaque appearance on extended exposure to water.

C2.3 Storage Stability

Requirement

The waterproofing material should be stable in storage.

Criterion

After a 30-day storage in a three-quarters filled, closed container,

the waterproofing material should show no signs of separation or settling

that cannot be readily remixed to a homogeneous stage.

Commentary

The success of a waterproofing treatment depends upon uniform

application to the substrate. If the nonvolatile vehicles have separated

from solution so that they cannot be remixed, this will not be possible

and the material should not be used.

64
C2.4 Resistance to Water Penetration

Requirement

The waterproofing material should produce a surface which is

resistant to water penetration.

Criterion

The brick test specimen, having 5 sides coated using the designated

rate and method, should have a water absorption of less than 20% by

comparison to the untreated test specimen.

The coated slabs shall be weighed then immersed, uncoated side up,

into 1.3 cm (1/2 in) of water. The slabs should be supported off the

base of the container to permit movement of water. At the end of 72

hours, the slabs shall be reweighed. The water absorption is the ratio

of the amount of water absorbed by the coated slab to the amount absorbed

by the original untreated slab. The appearance of the coated brick

should not change noticeably during immersion. After drying, the reflectance of the exposed brick should not differ by more than 5 units from

that of the coated unexposed brick when examined by directional reflectance measurements as described in Fed. Test Method Std. No. 141a, Method

6121 [1].

Commentary

The degree to which a waterproofing material prevents the infiltration of water is very important. Of the 55 materials tested, 27 materials

passed this requirement.

C2.5 Water Vapor Transmission

r Requirement

The waterproofing material should be sufficiently permeable to

water vapor when applied using the designated rate and method, to

prevent accumulation of moisture in the wall.

Criterion

The brick test specimen (coated using the designated rate and

method) should have a moisture loss of not less than 20% when tested in

the following manner.

The test specimens shall be submerged for 24 hours in water. The

slabs shall then be removed and the excess surface water removed by

blotting. The untreated face of the brick slab shall be placed downward

on a piece of aluminum foil slightly larger than the slab. The foil

shall be sealed to the brick slab. The weight of this test specimen

65
shall be recorded prior to placing it in a room at a temperature of 20-

24°C and a relative humidity of 50 ±5 percent with a free circulation

of air. After seven days, the test specimens shall be reweighed. The

difference in the weights is the amount of moisture lost by transmission

through the waterproofing coating. The water vapor transmission is the

ratio of this value to the amount of water absorbed by the original

untreated test specimen.

Commentary

Due to the relative humidity within a building, the usual direction

of moisture movement through masonry walls above grade is interior to

exterior. Thus, the waterproofing coating should have at least a small

permeability to the flow of moisture if accumulation of moisture in the

wall is to be avoided. Of the 55 materials tested, only 11 materials

did not meet this requirement; these were generally, materials of high

resin content.

C2.6 Resistance to Efflorescence

Requirement

The waterproofing material should be resistant to the formation of

efflorescence

.

Criterion

The brick test specimen (coated using the designated rate and

method) should show no visible signs of efflorescence on the coated

surface when tested in the following manner. The test specimen shall be

placed with the uncoated face downward in 1.3 cm (1/2 in) of a 10%

aqueous sodium sulfate solution. The brick slab should be supported off

the base of the container to permit movement of the liquid. After seven

days, the specimens should then be removed, allowed to dry, and examined

for efflorescence.

Commentary

The resistance to efflorescence test is designed to simulate the

movement of water soluble salts in masonry. Of the 55 materials tested,

only 12 materials had moderate or heavy efflorescence as examined

visually. If salts are present in the walls, they may crystallize

beneath the surface treated with waterproofing material and cause the

masonry surface to spall off. For this reason, the resistance to

efflorescence may be an optional crit2rion.

C2.7 Accelerated Weathering

Requirement

The waterproofing material should maintain a surface resistant to

water penetration after long exposure to accelerated weathering.

66
Criterion

The brick test specimen (coated using the designated rate and

method) shall be exposed for 1,500 hours in a Weather-Ometer , single

enclosed carbon arc, to a 102-18 cycle, i.e. 102 minutes light only, 18

minutes light and water spray. The exposed brick specimens should have

a water absorption of less than 15% and reflectance difference of not more than 5 units when tested as described in the criterion of C2.4.

Commentary

The degree to which a waterproofing material prevents and maintains

the prevention of water infiltration when exposed to weathering is

important. Since outdoor weathering takes too long, an accelerated test

is needed. Of the 15 materials tested in the accelerated weathering

test described above, 8 materials had a water absorption of less than

15%. Also, the same 15 materials exposed outdoors at the NBS weathering

site for 6 months had similar water absorption results.

C2.8 Continuous Condensation Exposure

Requirement

The waterproofing material should maintain a waterproofed surface

after exposure to continuous condensation.

Criterion

The coated face of the brick test specimens shall be exposed for

six weeks on a Cyclic Environmental Tester to a continuous condensation

cycle, 38 ± 2°C air temperature. The exposed brick specimens should

have a water absorption of less than 15% and a reflectance difference of

not more than 5 units when tested as described in the criterion of C2.4.

Commentary

The ability of a waterproofing material to continue to prevent

water infiltration when the coated surface is exposed to condensation is

important. While this test may be more than a real life situation,

12 of the 15 materials met this criteria.

67
APPENDIX D

THEORETICAL CONSIDERATIONS OF WATER FLOW

THROUGH A PORE IN A WALL

Dl. Background

A masonry wall consists of masonry units, brick or concrete block,

with a layer of mortar between adjacent units (Figure Dl) . In general,

the units and the mortar are porous on the microscopic scale. There may

be larger visible openings (cracks, flaws) between the mortar and the

units or within the mortar, particularly if the workmanship is not of

the highest quality.

Although the pores and cracks which are the paths for the flow of

water through a wall are of irregular shapes, some insights into factors

affecting water penetration can be gained by considering a model in

which the paths consist of parallel tubes perpendicular to the face of

the wall. The flow of water through the wall under various conditions

can then be described in terms of the total volume of pores and the

distribution of pore diameters. To develop this model, it is first

necessary to consider water flow through a single pore.

D2 . The Breakthrough Pressure

The pressure difference required to force water to advance through

a pore depends on the surface tension (a) of the water, the diameter

(d) of the pore, and the advancing contact angle (6) between water and

the surface of the pore (Figure D2). This pressure, which may be termed

the breakthrough pressure (P ) is given by:

pb-

-4 a cos

(1) [1]

Since P is negative when 8 is less than 90° , water will migrate spontaneously through the pore under these conditions and an opposing pressure would have to be applied to prevent its passage. On the other

Reference

[1] Schwartz, A. M. , Capillarity Theory and Practice, (Proc. Fifth Annual

State of Art Symposium on the Physics and Chemistry of Interfaces,

Washington, D.C. June 11-12, 1968), Book, Chemistry and Physics of

Interfaces - II, Ed. Gushee, D. E., pp. 1-13 (American Chemical Society

Publications, Washington, D. C, 1971).

68
Figure Dl. Model of a Masonry Wall

Paths for passage of water through a masonry

and mortar wall:

A incompletely filled mortar joints

B hairline cracks between mortar and masonry unit

C cracks through mortar

D mortar

E the masonry unit

69
Pore d

Figure D2. Model of a Pore

The breakthrough pressure, P , needed to force

water through a cylindrical pore depends on the

pore diameter, d, and on the advancing contact

angle, 0, between the water and the pore wall.

70
hand, a positive pressure would be required to force the water through

the pore if 6 was greater than 90°. (Certain waterproofing agents, i.e.

water repellent materials, function by increasing the contact angle 6 from less than, to greater than, 90°).

The smaller the pore diameter, the greater the breakthrough pressure.

This can be seen from the curves in Figure D3 in which P, is plotted for

b

various pore diameters and for five values of 6 . These curves were

calculated from equation 1. They show that, if is 120°, only pores

with diameters less than about 0.05 cm (0.02 in) will have breakthrough

pressures greater than 300 Pa (which is equivalent to the pressure of an

80.5 km/h (50 mph) wind-driven rain). Thus, it is unlikely that pores

with diameters greater than 0.05 cm (0.02 in) can be adequately waterproofed against an 80.5 km/h (50 mph) wind-driven rain by waterproofing

materials whose sole function is to increase the contact angle. If larger

pores are present, waterproofing can only be achieved by materials which

are able to, at least partially, fill the pores. Calculations for the

breakthrough pressures and wind forces are contained in Appendix E.

D3. Rate of Flow

The rate of flow of water through a cylindrical pore depends on the

pore diameter d (cm), the applied pressure P (Pascals), the length I

(cm) of the pore, and the viscosity n (Pascal seconds) of the water.

3 The rate of flow Q (cm /s) is given by

Q = * P d

(2 ) [2] ^ 128 n I

K

'

L J

Because of the high power of d in the numerator of equation 2, the rate

of flow at a given pressure increases rapidly with pore diameter. In

addition, the rate of flow over an area increases as the number of

Reference

[2] Dalla Valle, J. M. , Characteristics of Packings, Chapt. 6, Micromeritics, The Technology of Fine Particles, pp. 100-129, (Pitman

Publishing Corporation, New York, New York, 1943)

.

71
600

500 -

400 - BREAKTHROUGH

PRESSURE

R (Pascals)

300 -

200 -

00-

- 2

BREAKTHROUGH

PRESSURE Pb

( inches of water)

0.001 0.01 0.1

DIAMETER OF PORE, d (cm)

Figure D3. The breakthrough pressure, P^, , for water in cylindrical pores

of diameter, d, and its dependence on the contact angle, 6. Pores with

diameter greater than about 0.03 cm (.01 in) will always have breakthrough

pressures less than 500 Pascals (2 in water or 64.4 mph wind) and could

not be satisfactorily waterproofed against wind driven rain with a material acting as water repellent even if 6 was as high as 120°

.

72
2 4e capillaries increase. The number of pores per unit area (cm ) = -2—T

ttcK where is the porosity and d is the diameter (cm) of the pore. The

cm 2 „__ ,_ „, 2 Pd 2 £ rate of flow, Q through a one cm area is Q/cm

32 in

The results of calculations of the rate of flow, Q, through an array

of parallel pores of the same diameter uniformly distributed over the

whole area of a wall of thickness 10 cm (4 in) are given in Figure D4

for various total porosities, ; the pressure used in the calculation is

498.2 Pa (2 in) of water. Appendix E contains these calculations.

Here, it can be seen that, for a given porosity, the greatest rate of

flow is for the wall with the largest pores. This illustrates why

materials with larger pores (e.g. concrete block) are more permeable

than materials with smaller pores (e.g. clay brick), and why large pores

(e.g. cracks or imperfections in a masonry unit or mortar, or at their

interface) may give a disproportionately large contribution to the flow

of water through a wall.

D4. General Considerations

While the pores in a wall are certainly not an array of parallel

tubes as in the model discussed above, useful deductions can be made

from such a model. Thus it may be deduced that:

1. Other factors being equal, the rate of flow of water

under a given pressure will be low if the pore diameters are all small.

2. A small volume of large pores may allow the passage of

more water than a much larger volume of small pores.

3. Waterproofing materials that act as water repellents may

be effective in preventing flow of water from wind-driven rain

through small pores (e.g. less than about 0.05 cm (0.02 in) but

they are much less likely to be effective in preventing flow

through large pores (e.g. greater than about 0.1 cm (0.04 in).

4. To prevent flow through large pores, it is probably

necessary to use a waterproofing material which will effectively reduce the sizes of, or block, the pore openings, and

possibly, also act as a water repellent.

5. If dimensional changes which cause cracking take place in

the wall, a waterproofing material must not crack if it is to

remain effective.

These deductions draw attention to the fact that openings (e.g.

greater than about 0.05 cm (0.02 in) in a wall are those which are most

important and most difficult to deal with in waterproofing against winddriven rain. These include incompletely filled mortar joints, hairline

cracks between mortar and masonry units, larger cracks due to thermal or moisture movement or settlement and, possibly, flaws in the masonry units

73
300 -i

200 -

100 -

€=2

€

=

= 05

= .02

0.001 .003 001 0.03

DIAMETER, d(cm)

Figure D4. Rate of flow of water through a one cm area of a 10 cm thick wall of porosity e at pressure of 498.2 Pa. The

flow is attributable to parallel tubes of diameter, d

,

perpendicular to the wall surface under a pressure of 498.2 Pa

which is equivalent to 2 in of water or a 103.6 km/h (64.4 mph)

wind. For any value of e, the rate of flow increases as the

square of the pore size. The pores of clay brick are generally

in the 0.001 cm diameter range while hairline cracks and larger

visible openings will generally be between about 0.01 and 0.1 cm.

74
APPENDIX E

CALCULATIONS FOR THEORETICAL CONSIDERATION

OF WATER FLOW THROUGH A PORE

Wind Force Equivalents

2 (1) P = 0.000482 V [1] P = wind velocity head, inches water gage

v w v

V = wind velocity, miles per hour w

3 3 Based on air density of 1.2 kg/m (0.075 lb/ft )

1 in water = 2.54 cm = 2.54 g/cm 2 x 98.07 Pa = 249.1 Pa

(g/cm )

1 in water = 249.1 Pa

2 in water = 498.2 Pa

3 in water = 747.3 Pa

4 in water = 996.4 Pa

5 in water = 1245.5 Pa

1 mi = 1.609 km

1 mph = 1.609 km/h

from (1) above

when

w

mph km/h

10 16.1

20 32.2

25 40.2

30 48.2

40 64.4

50 80.5

60 95.6

70 112.7

80 128.7

90 144.8

100 160.9

then Pv

in Pa

0.05 12.0

0.19 48.0

0.30 75.0

0.43 108.1

0.77 192.1

1.21 300.2

1.74 432.2

2.36 588.3

3.08 768.4

3.90 972.5

4.82 1200.6

[1] Infiltration and Natural Ventilation, Chpt. 19, ASHRAE Handbook of

Fundamentals, pp. 333-346, (American Society of Heating and Refrigerating, and Air-Conditioning Engineers, Inc., New York,

New York, 1972) .

75
Breakthrough Pressure of Water Through a Pore

(2) P

b

- -4JLSS-! U ; o = surface tension of water

= 7.2 x 10~4 N/cm

from equation (2) above

8 = contact angle between water and surface

of pore

d = diameter (cm) of pore

P, in Pascals

b

d (cm) = 120° 6 = 110° 9 = 100' 95° 9 = 91'

1.0 14 .4 9. 9 5.0 2.5 .5

0.32 45 .4 31. 1 15.8 7.9 1.6

0.1 144 98. 5 50.0 25.1 5

0.5 287 197 99.8 50.1 10

0.03 455 311 158 79.4 15.9

0.01 1440 985 500 251 50.3

0.003 4554 3115 1581 794 159

0.001 14400 9850 5001 2510 503

[2] Schwartz, A. M. , Capillarity Theory and Practice, (Proc. Fifth

Annual State of Art Symposium on the Physics and Chemistry of

Interfaces, Washington, D.C., June 11-12, 1968), Book, Chemistry

and Physics of Interfaces - II, Ed. Gushee, D. E., pp. 1-13

(American Chemical Society Publications, Washington, D.C. 1971).

76
Diameter Equivalents

d (cm) d (in)

1.0 0.39

0.32 0.13

0.1 0.04

0.5 0.02

0.03 0.01

0.01 0.004

0.003 0.001

0.001 0.0004

Flow Through Capillaries

Water Flow Through a Tube:

4

(3) V = —

[3] V = volume delivered (cm ) 128 I n

P = pressure (Pa)

d = diameter of tube (cm)

t = time (s)

t = length of tube (cm) n = viscosity of liquid (Pa.s)

[3] Dalla Valle, J., Characteristics of Packings, Chpt. 6, Micromeritics

the Technology of Fine Particles, pp. 100-129, (Pitman Publishing

Corporation, New York, New York, 1943).

77
/ p (4) No. of capillaries/cm = —tj" [3]

e = porosity

d = diameter of capillary (cm)

rt\ w i a ^ a I 2 uP d4 g 4e P d

2 et

(5) Volume delxvered/cm = 128 l - x -pr - 32 a „

_3

For water at 15 C, n = 1.1 x 10 Pa-s

For a 10 cm long capillary, P = 498.2 Pa (2 in water) = 64.4 mph wind

from equation (5) above

3 2 V (cm Is) through a 1 cm area

d (cm) 0.2 (hi 0.05 0.002

2.8 x 10*1

2.8 x 10 _ 8.95 x 10

2.8 x 10

8.95 x 10

2.8 x 10_^

2.8 x 10*

2.8 x 10

„ „ , ~+2 , ~+2 , ~+l

1.0 2.8 x 10 1.4 x 10 7.1 x io r 0.1 2.8 1.4 7.1 x 10 7 -1 -1 -1

0.06 8.95 x 10.-1 4.5 x 10-17 2.2 x 10-2; 0.03 2.8 x 10 „ 1.4 x io ; 7.1 x 10

* -2 -2 -2

0.02 8.95 x 10 % 4.5 x 10 ; 2.2 x 10 t -2 -2 -3

0.01 2.83 x 10.-3 1.4 x 10 Z 7.1 x 10 , -3 -4

0.003 2.8 x 10 f 1.4 x 10 7 7.1 x 10

* -4 -4 -5

0.001 2.8 x 10 1.4 x 10 7.1 x 10

78
NBS-114A (REV. 7-73)

U".S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBS TN-8832. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE 5. Publication Date October 1975

Waterproofing Materials for Masonry 6. Performing Organization Code

7. AUTHOR(S) 8. Performing Organ. Report No. Elizabeth J. Clark, Paul G. Campbell. Geoffrey Frohnsdorff

V. PERFORMING ORGANIZATION" NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4615443

11. Contract/Grant No. IAA-H-37-72, Task 210

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Office of Policy Development and Research

Department of Housing and Urban Development

Washington, D.C. 20410

13. Type of Repor*- fk Period Covered Final 1/74 - 1/75

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

The initial effectiveness and durability characteristics of fifty-five clear masonry

waterproofing materials were evaluated using laboratory tests. This report contains

the results of initial performance tests including water absorption, water vapor

transmission, resistance to efflorescence and change in appearance. Durability tests,

including periodic measurement of water absorption after exposures to accelerated

weathering and outdoor exposures, were also conducted. Based on test results,

performance criteria for clear waterproofing materials were developed. In addition,

recommendations for the application of waterproofing materials were formulated. Finally,

the report contains a summary of a survey concerning field experiences with waterproofing and a brief theoretical discussion of water flow.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Accelerated weathering; durability of waterproofing materials; masonry; performance

criteria; waterproofing materials; water repellent materials.

18. AVAILABILITY gj Unlimited

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