Glazing Materials

Glazing materials such as gaskets, sealants and tapes are used to provide a seal, glass cushion and thermal isolation between the glazing material and the framing system. The function of the glazing material is to keep air, water and other items from entering the frame/sash area that can cause deterioration of the insulating glass, the building interior along with other parts of the building wall system. Three common glazing materials are discussed.

Gaskets can be made of solid or foam sections and be of neoprene, EPDM, vinyl silicone, and other rubber type materials. Gaskets will need to be resistant to the elements and be able to maintain their elastic and hardness properties to properly seal and cushion the glass used in the system. Gaskets can be keyed or wedge type depending on the system and design requirements. Many systems use an interior and exterior gasket with the thickness, hardness and profile engineered to apply a proper pressure on the glass with consideration given to tolerance of the glass, frame material, and gasket dimensions.

Sealants can be used individually or in combination with gaskets or tapes. Materials commonly used are silicones, polysulfides, polyurethanes, butyls, acrylics and other materials that are gunnable and can be tooled to provide a designed shape. The proper choice of sealant will depend on such items as the joint size, expansion/contraction expectations , materials joined/sealed, and the environmental conditions that the material may encounter. Many sealant types come with various capabilities that require careful consideration to make certain that breakdown, loss of adhesion, improper support or lack of proper isolation do not occur. Close attention to the performance characteristics and material compatibilities with various surfaces such as metal finishes, painted substrates, and other gasket/tapes must be considered for proper design of sealants used in a building wall system.
 
Tapes are commonly used in the design of a window system and provide similar functions as sealants and gaskets. Tapes are provided in solid and foam materials usually having a rectangular cross section. Tapes can be supplied with adhesive backing on one or two faces and can also be obtained in a butyl form with or without a sham. The design of a window system using tapes will require the tape to meet the pressure conditions expected as well as environmental and compatibility requirements of the building. Many designs utilize tapes as a back-up to a sealant application, a temporary cushioning material while sealants are curing or to provide a holding method prior to applying a final gasket.

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