What exactly is a sealant?
A sealant is an elastomeric material with adhesive properties that is applied between building materials to provide a barrier to the outside environment and enhance the aesthetics of the transition. Sealants contain an inert filler material and an elastomer to deliver both flexibility and elongation. When applied, they have a paste-like consistency, and as it cures, the sealant will solidify to a pre-determined hardness. Sealant products either shrink or maintain their body during the curing process. This variance will depend on the exact formulation and the type of technology used.
Sealants are extremely versatile. And while they contain many similar properties of adhesives, caulks, and putties, they remain very different. Typically, sealants have lower adhesive strength but higher flexibility than adhesives. They also serve more uses than caulks and putties, which are only intended to fill small voids. Regardless of application, sealants have three basic functions:
- To improve the appearance of joints by filling gaps between substrates
- To provide a barrier against water, moisture, air, dust, dirt, chemicals, noise and vibration. And in some cases, to provide electrical or thermal insulation.
- To maintain a seal for the expected lifetime, service conditions and environments.
Installers must prioritize a number of application and performance needs when choosing a sealant. The decision takes into consideration 1) the type of material the sealant will be applied to, 2) the joint dimension, 3) joint construction, and the 4) sealant’s performance characteristics. Let’s look at each of these in more detail.