A sealant is a substance used to stop fluids from passing through a seam or opening in a surface or material and is a type of mechanical seal. In building construction, sealants are sometimes synonymous with caulking and are also used to block the transfer of dust, sound and heat. Sealants can be weak or strong, flexible or rigid or temporary. Sealants are not adhesives, but some have adhesive properties and are called adhesive sealants or structural sealants.
Although not very strong, sealants have many properties. They seal the top structure to the substrate and are particularly effective during waterproofing by keeping moisture out of (or in) the components that use them. They provide thermal and acoustic insulation and can be used as a fire barrier. They may also have electrical properties. Sealant can also be used for simple smoothing or filling. They are usually required to perform several of these functions at a time.
A caulk sealant has three basic functions: it fills the gaps between two or more substrates; it forms a barrier through the physical properties of the sealant itself and its adhesion to the substrates. And it maintains hermetic properties over the life expectancy, usage conditions and environment. Sealants perform these functions through the correct formulation to achieve specific application and performance characteristics. However, aside from adhesives, there are few other functions that can replace the sealing process.
