Page 136 - Construction Waterproofing Handbook

ABOVE-GRADE WATERPROOFING 3.25
to exposed joints, then cured. Tape is then removed from the masonry units, leaving behind
a repaired joint surface with no change in wall facade color.
The thickness of coating added to mortar joints is variable but is greater when joints are
recessed. This system is applicable only to substrates in which the masonry units them-
selves, such as brick, are nondeteriorated and watertight, requiring no restoration.
Texture is easily added to a cementitious coating, either by coarseness of aggregate added
to the original mix or by application methods. The same cementitious mix applied by roller,
brush, spray, hopper gun, sponge, or trowel results in many different texture finishes. This
provides an owner or designer with many texture selections while maintaining adequate
waterproofing characteristics. A summary of the major advantages and disadvantages of
cementitious coatings are given in Table 3.12.
In certain instances, such as floor–wall
junctions, it is desirable first to apply the
cementitious coating to a substrate, and then to
fill the joint with sealant material in a color that
matches the cementitious coating. The coating
will fully adhere to the substrate and is com-
patible with sealant materials. It is also possible
first to apply cementitious coating to sub-
strates, then to apply a sealant to expansion
joints, door, and window penetrations, and
other joints. This is not possible with clear seal-
ers nor recommended with elastomeric coat-
ings, due to bonding problems.
Cementitious coatings are a better choice
over certain substrates, particularly concrete
or masonry, than clear sealers or elastomeric
coatings. This is because cementitious coat-
ings have better bonding strength, a longer
life cycle, lower maintenance, and less attrac-
tion of airborne contaminants. Provided that
adequate means are incorporated for thermal
FIGURE 3.10 Waterproofing concrete block and structural movement, cementitious coat-
envelope with cementitious coating. (Courtesy of ings will function satisfactorily for above-
Xypex)
and below-grade waterproofing applications.

TABLE 3.12 Cementitious Coating Properties
Advantages Disadvantages
Excellent bonding capability No movement capability
Applicable to both above-and Difficult to control uniform color and texture
below-grade installations
Excellent weathering capabilities High degree of expertise required for installation
Numerous textures and colors available Not resistant to acid rain and other contaminants
Can eliminate need for tuck-pointing Not applicable over wood or metal substrates