Putting in spot/down lights into insulated plasterboard

roosterman71

I've insulated plasterboard in the house and am putting in spot/down lights. Take these for example - https://www.astrolighting.com/products/1249017-minima-round-fixed-ip65

If I make the hole in the plasterboard, is it safe to put these in? The distance above the insulated plasterboard is sufficient and a bit extra to hold them before hitting the air tightness membrane. I'm worried about the actual insulation on the plasterboard being too close to the fitting.

In other places I don't have the same height and can put in pots into the membrane and the light has room above then. But would still have the same issue near the insulated plasterboard.

10-10-20

https://www.boards.ie/discussion/2058333486/putting-in-spot-down-lights-into-insulated-plasterboard

If they are LED (which all fitting are now) then there is little to worry about in terms of overheating. LED only gives off around 5W, so a lot less than the 50W of some halogen bulbs of old.

But I will caution you that by cutting into the insulated plasterboard, you're creating a hole in the (hopefully) well-sealed insulation envelope. I'd be avoiding that at all cost as the leakage of any warm air is going to lead to inefficiencies, as will removing the insulation at that spot.

Gusser09

Agree with the above. Possible cold bridge issues. Have you looked at surface mounted options?

roosterman71

Of course I don't want to cut the plasterboard insulation. I'm wondering if it being close to the fitting is a fire risk and if the electrician is likely to say no to it. The places where, if I'd have to cut it will, still leave me with ~300mm above the air tightness membrane.

https://www.boards.ie/discussion/comment/121682361#Comment_121682361

Yeah I have and will add them in a couple of places, but others places is not really possible on the sloped ceiling to have those sticking out. 100% be hitting your head by times

MicktheMan

If I make the hole in the plasterboard, is it safe to put these in? The distance above the insulated plasterboard is sufficient and a bit extra to hold them before hitting the air tightness membrane. I'm worried about the actual insulation on the plasterboard being too close to the fitting.

@roosterman71

Can you describe in detail the makeup of the construction that you are installing the lights into from inside to outside please.

roosterman71

https://www.boards.ie/discussion/comment/121683291#Comment_121683291

Of course.

Area 1: 62mm insulated plasterboard, 37mm cross batton, air tightness membrane, 220mm omnifit (this is a vaulted ceiling with truss construction)

Area 2: 12mm plasterboard, 37mm cross batton, air tightness membrane, 200mm rockwool, (this is a flat roof with 150mm (or 130) kingspan rigidboard over the internal ply)

Area 3: 44mm insulated plasterboard, 37mm cross batton, air tightness membrane, 200mm knauf, 50mm rigidboard (this is over bedrooms with attic space)