Silicone sealants for structural glazing and weatherproofing
Dow Corning is one of the longest-established names in construction silicone. Following the company's full merger into Dow, the construction silicone range was rebranded DOWSIL — so specifications, older drawings and product literature may refer to either name, and in most cases they mean the same materials.
Silicone matters more in glazing work than most people outside the trade expect. It is what holds structurally glazed glass to its frame, what seals the joint between a window and the wall, and what has to stay flexible through twenty years of thermal movement without cracking, hardening or pulling away.
The two roles are quite different. Structural silicone carries load — it bonds glass to metal and must be engineered, with joint dimensions calculated rather than estimated. Weatherseal silicone does not carry load, but it has to accommodate movement and remain watertight and UV-stable in full exposure.
Structural silicone is the material that holds glass to a building when there is no frame in front of it, and the sealant a specification names when the warranty depends on it. We use DOWSIL structural silicones (795, 995) for structurally glazed curtain wall and butt-glazed storefront, DOWSIL weatherproofing sealants (790, 791) for the perimeter joints on curtain wall and storefront, and the glazing and insulating-glass sealants where an IGU or a shower specification calls for them. The two-storey structurally glazed front at 24 Frost Street and the curtain wall at 300 East 50th Street are DOWSIL structural-silicone work.
Structural silicone carries load: it is applied in a controlled joint size, cured for days before the glass is loaded, and tested for adhesion on the actual substrates. Weather silicone keeps water out of a moving joint and is chosen for movement capability and colour. Using a weather sealant as a structural one is the failure mode of cheap structural glazing, and it is why we buy the named product and log the batch. See structural glazing and waterproofing.
We supply DOWSIL products with our installations and to contractors who need the specified material; tell us the product number, colour and quantity.
Yes: after Dow Corning merged into Dow, the construction silicone range was rebranded DOWSIL. Older specifications and drawings use either name for the same products.
Structural glazing: bonding glass to the frame in curtain wall and butt-glazed storefront where no exterior frame holds the glass. 995 is the higher-strength structural grade.
Weatherproofing sealants for the perimeter and expansion joints on curtain wall, storefront and windows, chosen for movement capability.
Weather seals and some structural joints yes, with cure time before loading; most structural glazing is done in the shop under controlled conditions and installed after cure.
Yes, with our installations and to contractors who need the specified product.
