Dormer roof- what's "unventilated air gap"?

2 Oct 2012
Reaction score
United Kingdom
Hi - please can anyone explain what all this means for a dormer roof 3mx3m (especially the "unventilated air gap" and "TLX Rafter Fix")?
Would the roof be good, durable, energy-efficient if built to specs below?

"3 layers felt on 80 Celotex on 12 ply decking on firrings at 1:60
unventilated air gap ????
TLX Rafter Fix ???? :!: :?:
150 rafters at 400 crs
unventilated air gap
12.5 plasterboard and skim

Cheers as always![/b]
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local