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Category: Sealants (Caulking) Product: Polyurethane Caulking / Sealant
Temperature Limitations: Above + 5 C (+40 F)
Rain Limitations: No rain for 1 hour
Wind Limitations: n/a
Humidity Limitations: Mist caulking after application if extremely dry to create a skin.
Continuous Conditions: 24 hours no freeze
Comments: Polyurethane Sealants are the Cadillacs of caulkings (more elastic and longer lasting), although slightly more difficult to work with than thermal plastics. They cannot be applied below freezing temperatures. They cure by reaction to moisture so higher moisture levels actually speed up curing -- hence very light misting when humidity is below 30% RH can speed up skinning to avoid dust collection. Can be applied to a moist surface but must be worked into the surface -- under water good surface contact is difficult to obtain. Can be painted after 7 days. Special roofing and flashing formulations are made for adhesion to asphalt roofing products.
Weather limitations on most renovation products can be located on the WEATHER tab above.
APPLICATION / INSTALLATION DETAILS
Polyurethane Sealants are the Cadillacs of outdoor caulkings (more elastic and longer lasting), although slightly more difficult to work with than thermal plastics.
The colour of dark and grey polyurethane caulking is little affected by UV, although some white Polyurethane caulking can shift to beige under direct sunlight. For colour stability good quality silicone sealants (good quality acetoxy systems and two part structural glazine silicone sealants) are regarded as having the best colour stability. MS (Modified Silicone -- silyl terminated polyethers) sealants come a very close second. Acrylics also have good colour stability.
There is a lot of information on caulking and caulking techniques on this web site; this will get you to most of it. First, what is a Sealant and what is a Caulking? Click here for Vocabulary. Then a brief overview might help with Which Caulking Should I Use? Click here for the right technique in using a caulking gun. Here is more for caulking in cold weather and keeping the product warm. And click here for more than you ever wanted to know about caulking .