Q.: Can you explain the difference between a sealer and a sealant?

A.: There is confusion about sealers and sealants due to inconsistent descriptions of these materials in articles and in some manufacturers' literature.

Sealers are products applied to surfaces, usually to reduce the penetration of undesirable materials, such as water or chlorides. Sealers may penetrate into the surface or form a very thin surface layer (typically less than 3 mils). Thicker surface treatments usually are called coatings.

Sealants, sometimes called caulks, are used for filling voids, gaps, cracks, and joints. A variety of sealants are available for different applications and types of construction. Sealants may be rigid or flexible, and nonsagging or self-leveling, depending on performance requirements. A related term, seal, describes a gasket, strip, or gland, usually between panels or at isolation or expansion joints. Most seals are prefabricated, but some are field-molded.