In article , fred writes
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.

Yes, logic suggest this, but embarrassing stories win over logic every time:

Chum decides to make boat dock pontoon out of fibreglass and, to guard
against flooding in case of damage, fills it (them actually) with expanding
foam. Inevitable damage does occur and pontoon sinks faster than you can
say impervious steam liner :-)

On reflection (this was a while ago), I think it was wave action breaking
over the pontoons, rather than damage, that ended up with them
waterlogging, but they definitely ended up sinking.

But (back on topic) I agree that short term exposure, of a matter of weeks,
will do no harm
--
fred