In article ,
Grunff writes:
fred wrote:

Also it's not a closed cell foam so it will soak up moisture like a sponge
which could lead to rot problems in the future. I'm very careful where I use
it.

I've heard this said quite a few times, but I'm really not sure. Think
about how it's formed - lots of bubbles of propellant expanding away in
a PU matrix. I'd say it is largely closed cell, with only a few through
paths. Its moisture absorbance is quite low.

I used it as replacement insulation on bottom of a freezer after
the initial fibre matting became waterlogged (or rather, ice logged).
I also assumed it was closed cell and wouldn't need any further
surface sealing, but I was wrong, although it did take about 3
years before it became completely water/ice-logged.

--
Andrew Gabriel