How much space to leave around the down light in kings

[compact]

Quick one, the electrician pulled out all the kingspan, mentioned something about need to leave space and can put some back in, but is obviously leaving to the plasterers, whose job it isn't. So down to me how much space should I leave around the spot? I have read 4 inches and 6 inches.
We've a good amount of , a joists are 130mm plus 70mm for the extra spur. Width joists 230 and spurs 320.
Cheers

 

[chivers67]

I'd push this back to your Electrician, he's the one installing the lights. What type and size have you got?

 

[compact]

We haven't chosen the spots yet, so on us to . They will most likely be average size, .

 

[Notch7]

I cant tell if thats a warm roof or cold.....

Cold roofs arr no good for downlights.

I always do a warm roof, leave void on inside. Our electrician always uses those shallow downlighters that are only 60mm or so.

 

[chivers67]

http://enlitelighting.com/gb/ProductDetail/EN-DE82 < I'd recommend something like this have a look at the pdf data sheet which suggests they can be covered by upto 300 mm of fibre based insulation. You could also make at least one an emergency light if you wish. The bezels are extra btw.

 

[compact]

Cheers the look nice

We do like these
https://www.astrolighting.com/products/5739-minima-round-adjustable-fire-rated

As they are very minimal, hence the name.
But am unsure about distance to insulation
"Not Suitable for mounting
on flammable materials.
Not suitable for covering
with thermal insulation"

 

[chivers67]

The recess depth is 152 on the Astros and 92mm cut out compared to the Enlites 100 and 80mm cut out.

 

[Lectrician]

I wouldn't be making ANY holes in the insulation. It's there for a reason. With a roof structure like that (and other flat roofs etc), this will lead to a cold spot. You will get condensation around the light, the ceiling can go mouldy in that area, and the light itself, if metal, could rust. I have seen this several times in installations, although mainly in bathrooms/kitchens. DON'T go breaking the effectiveness of the insulation - You will regret it.

 

[bobsuerita]

I wouldn't be making ANY holes in the insulation. It's there for a reason. With a roof structure like that (and other flat roofs etc), this will lead to a cold spot. You will get condensation around the light, the ceiling can go mouldy in that area, and the light itself, if metal, could rust. I have seen this several times in installations, although mainly in bathrooms/kitchens. DON'T go breaking the effectiveness of the insulation - You will regret it.

as above

 

[bobsuerita]

https://talk.electricianforum.co.uk/uploads/monthly_12_2014/post-16173-0-69004200-1417990017.png

try and achive this you have the depth

 

[compact]

The electrician said that you need to leave space around and above due to heat and then there is the air gap between the felt and insulation. Thus if and when we put it back in, he said we would need 6inch holes through to the felt.
I agree that insulation is important, just not sure of the fire risk from down lights and kingspan

 

[compact]

Just seen the link to the image, cheers.
If looks like we could achieve a 20mm air flow gap, 30mm insulation and then the 150mm for the light plus all the other insulation around it.
Thanks

 

[Taylortwocities]

If Building control spot that, they will jump on it big time. It will greatly reduce the thermal characteristics of the roof construction.

 

[Lectrician]

You need to maintain airflow behind the insulation too. There are times you need to stand back and say “sorry, downlights are not possible”. Alternatives are the LED panels, they are the thickness of the plasterboard, but do need a little room from a driver behind. They come in various diameters, but don’t look like traditional downlights.

Another alternative is to drop the ceiling. Collingwood LED H2pro downlights are low profile, and dropping by counterbattening 50mm would likely be fine.

 

[studentspark]

I know its quite late in the build, but do you really want spotlights in that location.
Shining right in your eyes, I would be tempted to find another way to light the room, before the plasterboard goes up.