Sealant

Sealant is a substance used to block the passage of fluids through openings in materials,[1] a type of mechanical seal.

In building construction sealant is sometimes synonymous with caulk (especially if acrylic latex or polyurethane based)[2] and also serve the purposes of blocking dust, sound and heat transmission.

They seal top structures to the substrate, and are particularly effective in waterproofing processes by keeping moisture out (or in) the components in which they are used.

A sealant may be viscous material that has little or no flow characteristics and which stay where they are applied; or they can be thin and runny so as to allow it to penetrate the substrate by means of capillary action.

Typically, sealants are used to close small openings that are difficult to shut with other materials, such as concrete, drywall, etc.

Types of sealants fall between the higher-strength, adhesive-derived sealers and coatings at one end, and extremely low-strength putties, waxes, and caulks at the other.

Sealants generally contain inert filler material and are usually formulated with an elastomer to give the required flexibility and elongation.