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Installing recessed lighting in a Celotex insulated flat roof
In article ,
(SteveRoche) writes:
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.
Well, it's rather a strange thing you seem to be doing. On one hand,
trying to insulate your house to conserve energy, and on the other
hand using such inefficient lighting you've got loads of waste energy
to dump through your house insulation ;-).
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 ?
Some of them burn down their houses -- seriously. Celotex may not
burn well itself, but in a fire I suspect it will give off loads of
cyanide, pretty much guaranteeing you won't get out. I would want
a good fireproof/heatproof barrier between any cellotex and possible
ignition sources. I wouldn't dream of putting recessed 50W spotlamps
anywhere near the stuff. If you do, at least make sure you use GU10's,
(aluminised) and not GZ10's (dichroic -- cool beam -- which will dump
even more heat into the ceiling). I would have suggested low voltage,
but I don't think aluminised LV reflector lamps are available any more;
I only see dichroic ones. Personally, I wouldn't dream of using large
numbers of downlights for general lighting. They are more appropriate
to task and accent lighting.
--
Andrew Gabriel
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