http://photos.dionic.net/v/public/bu..._0003.jpg.html

Next year sometime, I'll be wanting to insulate the above wall and serveral
others like it (dormer) with celotex.

I can arrange for facia vents on the front of bother dormer roofs, fiddly
but quite possible.

Now, those timbers in that photo are 3x3". Notionally plenty of air space if
I just cover over with say 75mm celotex.

The fly in the ointment are those noggins and similarly the windows.

Even if I cheat and batten out to allow only a 25mm airflow over the top of
the timbers, that's taking 4 inches off the room, whereas if it weren't for
all that, I could stick 25mm celotex between the wood and 50 over losing
only 2 inches. As these extra 2 (maybe 3) inches apply to all walls, I'm
losing space fast trying to insulate better. And I really out to be aiming
for 100mm celotex, although 75mm will be twice as good as the miserable bit
of glass wool that used to be there.

Other than reroofing with Tyvec or turning it into a cold roof (the roof is
fine - this is not really a practical proposition expense wise), any ideas
on how to maintain air flow?

Could I maybe drill some holes though the noggins (though that leaves the
problem of the windows)?


Cheers

Tim

--
Tim Watts

This space intentionally left blank...