"The Natural Philosopher" wrote in message
...
L Reid wrote:



I thought the 'boardy' stuff was a bit more pleasant to work with than
the
rockwool?


Not much :-(

Should I worry about condensation, or should I be OK with a slate
roof with no underfelt? It certainly let water in easily enough last
week
when a slate had moved.


Hmm. Not really sure about rain ingress. Celotex is double foil backed -
you wedge it between the rafters and then use special foil tape to get
it sealed to the rafters - that puts a vapour barrier on the hot side,
and you leave a gap to the slates for air circulation over teh rafter
tops.

Pay a lot of attention to absolute draughtproofing. It makes a HUGE
difference on a cold windy day. I may yet hit my loft with poly foam and
silicone gun to get the last few out...

Underfeltinmg (sarking?) is very useful to cut down the wind level. I'd
definitely say that if budget allows, a roof off, felt and relay is
indicated.

Once the insulation is up, dry lining makes a decent finish.

You should leave the eaves open to allow air to circulate above the
insulation.


Thanks for that. I think I'll be going down the route of putting the
insulation on the loft floor, rather than attaching it to the rafters, and
was wondering if I'd still have to deal with the possibility of condensation
if doing this. The roof is also partially within the bedrooms so I do have
an angled loft-space to take care off. Pic here of a similar building :

http://home.golden.net/~elspeth/images/Colonies021.jpg

Cheers!

Leigh