Caulking
Background
Sealants (caulking) are required at numerous locations in a variety of wall systems and the associated components. This is a critical step in creating and maintaining a weather resistant barrier to air and moisture infiltration at the exterior building envelope. Commonly, sealants are used on curtain wall systems, control joints for concrete and masonry wall assemblies, structural glazing, and perimeter or termination joints at rough openings.
Failure
There are many types of sealant failure, but the most common are adhesive failure, which is characterized by a loss of bond between the sealant and the substrate, and cohesive failure, which is recognizable by rips or tears within the sealant, often oriented parallel to the joint. Other common sealant defects include crazing and chalking of the surface. Exposure to sunlight can cause UV degradation in the material and may result in a network of cracks in the exterior face of the sealant, usually a strong indicator that the sealant performance is diminished and nearing the end of its service life. This exposure to UV can also lead to a chemical breakdown of the sealant, resulting in chalking – where a powder forms on the face of the sealant.
Contractor Selection
In view of the typically high costs associated with safe access on high rise buildings, and the labour-intensive nature of sealant removal & replacement relative to the limited cost differences between sealant materials, it is important that building owners and managers understand how long-term costs and ongoing maintenance can be reduced by selecting a more costly, but superior, sealant material now, and awarding the work to an experienced sealant installer.
Even with a comprehensive evaluation of sealant selection, the long-term performance of a caulked joint is ultimately dependent on the workmanship.
Location
701 3 Ave SW, Calgary, AB T2P 5R3, Canada