I'm planning to install recessed lighting (GU - 50W, 8 of them) in the ceiling of a flat roof extension (the ceiling is 12'x18' approx,
200mm joists). The ceiling is to be insulated with Celotex (140mm), but I'm told by Celotex that you should not install recessed lights in a ceiling insulated with Celotex ! The main reasons they give are that it compromises the U value of the roof, since you have to cut holes in the celotex to accomodate the recessed fitting.I looked at fire-caps to sit over the recessed lights - they help with heat loss and noise, and of course stop potential fires getting into the ceiling too quickly - but again the fire-cap people suggest not to put recessed lights into a Celotex insulated ceiling.
Help ! I see plenty of programs/articles where people have recessed lights in flat roof ceilings - how do they do it ? Do they use Celotex ? How big are the holes they cut in the Celotex ? Do they use something else to insulate the ceiling ? Do you use fire-caps ?
Any ideas much appreciated.
Steve...