Source: ARCHITECT Magazine
Publication date: February 1, 2007
By Susan McClendon
Modern commercial structures rely heavily on joint sealants to prevent water damage to buildings and their contents. While residential buildings use water-shedding techniques such as sloped roofs, lap siding, and overlapping flashings, many commercial designs don't; if a joint sealant fails, there is little or no barrier to leakage. Unfortunately, in today's building environment, there are many points in the design and construction process where bad judgment or bad behavior results in sealant failure. Read the following for tips on how best to avoid these situations.
Common UsesJoint sealers are used to close open joints to keep water and air out (both exterior and interior); for appearance and cleanability (in interior surfaces where water resistance is not an issue); and to reduce sound transmission through cracks (usually interior and internal to composite assemblies). If none of the above considerations is applicable, joint sealers are probably not necessary. Although there are many types of joint sealers, this review covers joint sealants only—pourable or gunnable material of mastic consistency that sticks to each side of a joint.
Exterior. Most modern homogeneous rigid exterior substrates are purposely jointed, to allow movement without damage to the material. The two principal causes of movement are thermal expansion and contraction and seismic movement.
Some substrate...
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