andrew wrote:
This cold weather has really shown up a problem with an unheated
converted agricultural implement shed. The building is used to store
generators, lights and small tools and has had a plasterboard ceiling
added, to stop dust and bird crap spoiling the kit.

The gable ends are ventilated and the roof is simple 4 by 2 rafters
with corrugated iron, the corrugations vent at the eaves and the
ridge capping.

This roof is plainly a good radiator on cold nights and vapour from
ambient air is condensing, and sometimes freezing, on the inside then
dripping onto the plasterboard below.

I'm considering stapling tyvek in between the rafters or even full
length under them but worry about the effect this will have on old
untreated roof timbers?

AJH

Not sure what tyvek is but it sounds expensive.
Why not use normal breathable roofing felt? - it's cheap and can be stapled
to the joists just the same and will also cut down the amount of
condensation reaching the tin sheeting, with the added bonus of allowing the
old timbers to breathe.

--
Phil L
RSRL Tipster Of The Year 2008