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?
does not help.
On Tue, 22 Dec 2009 23:21:31 +0000, "george [dicegeorge]"
The two most commonly used spray foam products are low-density,
open-cell SPF (nominally referred to as 1/2 pound) and
medium-density, closed-cell foam (2 pound). Foametix offers both
types of SPF, dubbed Blue Max 050 Open-cell and Blue Max 200
Open cell foam will absorb moisture from the air whenever the pipe is
at the dew point, which will then freeze should the opportunity arise.
Closed cell foam by its nature will not.
Armaflex is a preformed pipe insulation which is closed-cell.
Armaflex is also neoprene, so that the cells flex if they do happen to
be wet and frozen. Stiffer foams (PU, PIR) will tend to crumble
gradually over the years.
One of my favourite things in the workshop ever is a roll of "Armaflex
gaffer tape", 3mm sticky-backed neoprene. It makes non-slip pads under
furniture, anti-vibration handle wrappings on power tools, draught
excluders on windows, the works.
2 days ago i filled the gaps at the top of an exterior wall with foam,
was going to cap it with a thin layer of concrete,
(before the slates go back on).
But the foam may move with heat variations,
the concrete may crack,
and water seep in,
so i guess that to do a long-lasting job
when the snow's gone i'll have to clear it all out
and use concrete to infill.
there were huge gaps in the top of the wall (north facing)
filled with straw from decades of birds.
It will take perhaps 20 buckets of cocrete lugged up the ladder,
and a few hour removing the foam,
but i think i'd better do it
as the foam wouldnt last many decades.
today i started ripping the interior foam from the top of the wall
where I put it last week,
and i've ordered this:
Smallest of the Touch 'N Foam Kits -
(15ft2 or 1m2 at 1 inch or 25mm)
which I hope is the correct kind of exterior closed cell foam
for using where water might dribble in.
george [dicegeorge] wrote:
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