Sloping roof
- Thread starter 46philh
- Start date
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These days a roof as described will usually have great big blocks of polystyrene insulation (often called by the trade name Kingspan) filling the space between the roof timbers and between the tiles and the plasterboard. This makes fitting downlights a real headache and increases problems with heat retention. It also degrades the insulation properties of the polystyrene, so I reckon you'd be better off looking for another lighting solution.
pj
pj
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I expect that your proposed extension will have the involvement of Building Control?
He/she will mandate, nay insist, that you do not make a swiss cheese out of all of that insulation that is DESIGNED to keep you warm.
In any event, downlights make a poor job of lighting up a work area so (IMO) consideration of another lighting solution is your best bet.
He/she will mandate, nay insist, that you do not make a swiss cheese out of all of that insulation that is DESIGNED to keep you warm.
In any event, downlights make a poor job of lighting up a work area so (IMO) consideration of another lighting solution is your best bet.
Just finished first fixing a job like this. large lean-to extension with 21 down lights!! Wouldn't be my choice of lighting but the customer is always right eh!
150mm roof timbers to be filled with 125mm insulation spec'd by building inspector. customer suggested running cables, insulating over and getting it checked by building control. then coming back and cutting holes through the insulation. I wasn't too pleased with this and suggested creating an insulated box around each light. Customer had already luckily bought 30mm and 100mm celotex instead of 125 solid as it was cheaper so we are going to run the 30mm at 100mm depth right through the extension over the top of the lights then cut the 100mm to create an air gap around each light. so we will have a 100mm deep x200mm square hole to sit the light in. so no cold bridge and a nice air gap. building inspector was happy with it as long I was so all good!
You could also consider using multi foil insulation above the roof timbers leaving more space in the void for lights. Depends what stage your build is at!
Hope that helps.
150mm roof timbers to be filled with 125mm insulation spec'd by building inspector. customer suggested running cables, insulating over and getting it checked by building control. then coming back and cutting holes through the insulation. I wasn't too pleased with this and suggested creating an insulated box around each light. Customer had already luckily bought 30mm and 100mm celotex instead of 125 solid as it was cheaper so we are going to run the 30mm at 100mm depth right through the extension over the top of the lights then cut the 100mm to create an air gap around each light. so we will have a 100mm deep x200mm square hole to sit the light in. so no cold bridge and a nice air gap. building inspector was happy with it as long I was so all good!
You could also consider using multi foil insulation above the roof timbers leaving more space in the void for lights. Depends what stage your build is at!
Hope that helps.
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