Page 133 - Construction Waterproofing Handbook

3.22 CHAPTER THREE
for integral waterproofing or water repellency. An integral bonding agent is added to the
dry mix, or a separate bonding agent liquid is provided to add to the dry packaged mater-
ial during mixing. The cementitious composition allows use in both above- and below-
grade applications. See Fig. 3.7, for a typical above-grade cementitious application.
Since these products are water-resistant, they are highly resistant to freeze–thaw cycles;
they eliminate water penetration that might freeze and cause spalling. Cementitious coat-
ings have excellent color retention and become part of the substrate. They are also non-
chalking in nature.
Color selections, such as white, that require the used of white Portland cement, increase
material cost. Being cementitious, the product requires job-site mixing, which should be
carefully monitored to ensure proper in-place performance characteristics of coatings.
Also, different mixing quotients will affect the dried finish coloring, and if each batch is
not mixed uniformly, different finish colors will occur.

Cementitious properties
Cementitious coatings have excellent compressive strength, ranging from 4000 to 6000 lb/in 2
after curing (when tested according to ASTM C-109). Water absorption rates of cementitious
materials are usually slightly higher than elastomeric coatings. Rates are acceptable for water-
proofing, and range from 3 to 5 percent maximum water absorption by weight (ASTM C-67).

FIGURE 3.7 Spray application of cementitious waterproofing. (Courtesy of Vandex)