Insulation board and downlights

[SIman]

I am about to install 2 downlights (GU10s) in a pitched roof/ceiling that is almost fully filled with Kingspan insulation board. How far back should the insulation board be cut for a GU10 fixture? Obviously it's a trade off between thermal performance of the ceiling and the amount of space needed to cool the fixture. Anyone know any figures for this? The ceiling is plasterboard/40mm Kingspan over rafters/90mm Kingspan between rafters/50mm air gap/felt/clay tiles. I actually only want to fit energy saving GU10s, but I guess I'll have to make the fixture ok for 50W GU10s to satisfy Mr Building Inspector!

 

[2face]

i am sure the distance is 110 mm from anything.. this figure is in my mind .
to close and the bulbs fizzle to nothing .

 

[Adam_151]

I am about to install 2 downlights (GU10s) in a pitched roof/ceiling that is almost fully filled with Kingspan insulation board. How far back should the insulation board be cut for a GU10 fixture?

You should consult the manufacters instructions, if you can not locate this information, you should contact the manufacters themselvees

Obviously it's a trade off between thermal performance of the ceiling and the amount of space needed to cool the fixture.

Therefore it would also be prudent to speak to buildings control at the council as well

Anyone know any figures for this? The ceiling is plasterboard/40mm Kingspan over rafters/90mm Kingspan between rafters/50mm air gap/felt/clay tiles.

Try approved document L, otherwise ask the building inspector

I actually only want to fit energy saving GU10s, but I guess I'll have to make the fixture ok for 50W GU10s to satisfy Mr Building Inspector!

I'm not sure (although I'd hope so) , but it would certainly be very much common sense to do so