Page 269 - Construction Waterproofing Handbook

5.28 CHAPTER FIVE
TABLE 5.4 Acrylic Sealant Properties

Advantages Disadvantages
No primers required Long cure stage
Good UV resistance Low-movement capability
Minimal surface preparation Poor impact resistance

Although butyls have low-movement and recovery characteristics, they have excellent adhe-
sion performance. They bond tenaciously to most substrates and have excellent weathering
characteristics. Butyls should not be used on water-immersed joints or joints subject to traffic.
Butyl sealants are used in metal curtain wall construction because of their ability to
function in very thin applications. As long as movement is within the capability of a butyl,
materials will function properly in metal wall construction splice joints.
Butyls are relatively easy to install, available in one-component packaging, and easily
gunable or workable. They require no priming and are paintable. (See Table 5.5.)

TABLE 5.5 Butyl Sealant Properties
Advantages Disadvantages
No primers required Low-movement capability
Excellent weathering High shrinkage rate
Little surface preparation Poor recovery

Latex
Latex sealants are typically acrylic emulsions or polyvinyl acetate derivatives. Latex mate-
rials have very limited usage for exterior applications. They are typically used for interior
applications when a fast cure time is desired for painting. Latex sealants have an initial set
of tackfree time of less than 1 hour, fastest of all sealant materials.
Latex materials have very low movement capability, high shrinkage rates, and only fair
weathering and adhesion properties. Their exterior use is limited to window or door
perimeters where it is desired that the sealant match the frame color opening. Latex mate-
rials should not be used in areas subject to water immersion or traffic. (See Table 5.6.)

Polysulfides
Polysulfide materials are produced from synthetic polymers of polysulfide rubbers.
Polysulfides make excellent performing sealants for most joint use. However, urethanes
and silicones frequently have become specified and used due to their excellent recovery
ability and joint movement capability.

TABLE 5.6 Latex Sealant Properties

Advantages Disadvantages
Past cure stage Low-movement capability
Paintable High shrinkage rate
One component Poor weathering