Expert: Ted Barnhill (Principal, Design45 LLC) - 12/16/2008

Question
Some replacement windows we ordered have arrived and the contractor wants
to install them soon.  We live in Wisconsin and was wondering if it is wise to
install these windows if temperatures are very cold.  I was mainly concerned if
caulking would not work well below a certain temperature.  I know he
wouldn't want to do it if it was below zero, but he saw no problem with doing
it later this month or in January. Is there a point where it would be too cold
for caulking to seal properly?

Answer
Gregory,

You are correct to ask the question, as many common exterior sealants will fail if applied when air or surface temperatures are too low (below 40 F).  However, there are several sealants that can be successfully applied in very cold temps.  100% silicone can be used, but is not paintable.  A better, newer choice is synthetic rubber caulk, which is paintable and can be applied in winter.  The drawback is that it has high VOCs (read: it is stinky and bad for air quality), so don't use it indoors.

Ask your contractor what sealant(s) he intends to use before he begins; if you are concerned he should have no problem showing you the packaging that specifies the application temps and paintability.  Enjoy your new windows!  -Ted