Stone Joint Sealant depends on its ability to maintain the properties needed to function in the joint

A sealant’s longevity depends on its ability to maintain the properties needed to function in the joint. Those properties include adhesion, cohesive strength and modulus.

There are many factors to consider when choosing a sealant for a specific joint design. First, does the movement capability of the sealant match up with the design requirements for the installed conditions? Then, there are the physical and chemical properties of the sealant such as modulus of elasticity, stress/strain recovery, tear strength, fatigue resistance and more.

In order to perform as intended, sealants must be able to deform and stay in place while the building moves. The design must include tests and specifications that establish the ability of the sealant to handle movement and not experience adhesive or cohesive failure for an acceptable amount of time.

Generally, the shape factor (mean width versus mean depth) of the sealant plays an important role in this capability. Sealants with wider and shallower profiles tend to stretch more readily when subjected to movement and may be expected to have longer service lives than narrower and deeper sealant configurations.

Proper surface preparation is essential for maximizing the bond between the sealant and concrete masonry. Following the sealant manufacturer's recommendations for cleaning and/or priming can minimize adhesion failures.

Most stone and masonry installations are subject to movement, either from thermal expansion and contraction or structural movements within the wall. A wide range of materials are available to help control this movement. The selection of the proper joint sealant for a particular application requires consideration of the specifics of the project.

Some factors to consider include the ability of the sealant to resist abrasion, corrosion, water penetration and chemical exposure. Specifiers may also want to consider the fire rating or acoustical rating of the sealant, availability of different colors, or ease of clean up after installation.