The use of sealants in facades became more widespread in the 1950s and 1960s with the increasing use of curtain wall construction. While most sealants specified for new construction today are silicone or urethane-based, older buildings may contain polysulfide and acrylic-based sealants.
For investigators trying to identify sealants used on older buildings, it is often useful to know which sealants were in common use when the building was constructed, or when the building was repaired. This paper briefly discusses and reviews the history of the use of commonly used building sealants over the last fifty years, detailing when specific sealant types were first developed, when they came into widespread use, or fell out of favor.
Historically, sealant selection has depended upon many factors such as the type of substrate, movement requirements, prior sealants used, cost and aesthetics. Improvements in performance capabilities of sealants and innovations such as structural glazing are discussed.
Some sealants have been found to contain hazardous substances. For example, some polysulfide sealants applied during the 1960s contain polychlorinated biphenyls (PCBs). Issues related to hazardous materials in sealants will be discussed as well as the performance consequences of the current change to sealant products to make them less harmful to the environment.