Watching Holmes on Homes tuesday evening on a Shed channel
he was fixing some freezing plumbing which had been half insulated
with what he called 'half pound foam'
(which I guess is the expanding foam we get here in cans).
He said in cold weather it shrinks and creates gap through which cold
air can flow.
He coated it with a blue foam, which he called 'Two pound foam'.
What is this stuff?

http://wiki.diyfaq.org.uk/index.php?...Expanding_Foam
does not help.

[g]