Sealants - their properties and performance.

Caulks and sealants are used to fill and seal joints, in order to prevent draughts and the intrusion of rain and dust. There are two types of joints; non-working joints in which there is little or no movement of the joined parts, and working joints which are designed to allow movement. Discusses for each type of joint, factors to consider when selecting a sealant and suitable types of material. Notes that for working joints sealants are classified by federal specification according to the amount of movement they can tolerate.< Part 2 of the article discusses different types of sealant:- solvent-type acrylics; polysulfides; polyurethanes; silicone sealants; high, low and medium modulus silicones. Describes the application for which each type of sealant issuitable. Summarises characteristics of sealants.