Downlighters in a "Cold Roof"

[Athelstan]

A plasterboard ceiling as been taken down in a flat roof kitchen extension, to reveal old fibreglass insulation, which is to be replaced with foam 100mm sheets. The joist depth is 150mm or 6" and is an existing "cold roof" extension so a 50mm air gap must be maintained for ventilating condensation. I have seleted an Aurora light fitting which is 230v, fire protected and compact in design, only 110 in depth, of which some will be taken up by skim and the 12.8mm plasterboard. My questions are this,
1. Because it is a cold flat roof extension and considering the depth of lighting and insulation depth there is no point in insulating above the fitment if only to maintain the 50mm air gap?
2. How much insulation out of the foam board boards should be cut out cosidering there is a "free air" gap above the downlighter?
Any thought will be appreciated

 

[SirKit Breaker]

Follow the manufacturers instructions for these things. They will give you the minimum clearances. I have used the ones you mention and they are really good in tight places, but they can and will cause problems with overheating if not installed correctly. If you dont fit them properly, then you are going against, the building regs, wiring regs, and the manufacturers instructions. I will let you work out for yourself where the brown stuff will land if something goes pete tong.
Cheers...........Howard

 

[Penance]

Looked at downlights for a kitchen extension with a cold roof as you describe.
In reality it is nigh on impossible to install them with the required clearance and still maintain the required insulation level and moisture barrier, happy to be shown otherwise!

It may be possible but I went with surface mounted lighting.

 

[bugsy]

Aurora Sola range you can insulate over the top

 

[Athelstan]

Thanks bugsy. i didn't know about the new Sola range from aurora, think they could be the answer. Thanks.

 

[telectrix]

or go with LEDs

 

[Athelstan]

Too dear telectrix, the sola range works out at £19 a pop, which is enough. Couldn't contemplate the cost of LEDs! Think the Sola range has sorted the problem out.