The Natural Philosopher wrote:
: LJMeek wrote:

: Personally I think this fashion for howling draughts in yer loft is so
: much bunkum.

: It arose I suspect when people started felting..no natural draught
: through the tiles or slates. And then adding ceiling loft insulation
: made the loft a very cold place indeed..and condensation then rears its
: ugly head.

: So we were then told to fit vapour barriers between the habitable space
: and the loft, but they still kept these massive ventilation requirements.

: Frankly I feel that a couple of vents at each end of a gable roof is by
: far and away all you need. But the regs say otherwise.

I've also heard that when replacing old wooden soffit boards with
modern plastic ones the vents are required because the wood was
'breathable' while the plastic effectively makes a seal. I found that
after the installation of plastic soffit boards with vents on a house
with rooms built into the loft and not much insulation between the
loft-rooms floors and second floor ceilings (the loft extension was
done in the late 60's), a cold wind really chills those rooms.

Tom.

--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T.Crane at rhul dot ac dot uk
Fax: +44 (0) 1784 472794