Page 287 - Construction Waterproofing Handbook

SEALANTS 5.45

FIGURE 5.42 Proper tooling of joint ensures that material adheres to sides of joint.
(Courtesy of SWRI)

Applying sealants in the hottest part of
the season in a particular locale (when the
joint is completely contracted or in its
smallest width stage) is more likely to cre-
ate material failures. This is because the
joint will always be in an expansion mode,
constantly pulling at the sealant material as
shown in Fig. 5.47.
Cold-weather sealing, therefore, offers
advantages over hot or mild weather, and it
is advantageous to seal when the joint is in
its most contracted stage. Thus, sealing
should not be completed when the condi-
tions are likely to put the joint in a complete
expanded mode, when the sun and temper-
FIGURE 5.43 Sealant material applied too thickly
will result in cohesive failure. (Material cannot ature are at their peak. Therefore, sealant
stretch sufficiently, and splits apart) applications should keep ahead of the sun
around a building, working in the shade as
much as possible. Applications should be completely avoided on west elevations at the
day’s peak temperatures around midafternoon.

Cold-weather sealing
Of the many problems that might occur in sealing joints in temperatures below freezing,
the most serious is joint contamination by ice. In freezing temperatures, a joint surface can