Hello,
We had a larger flat roof dormer extension built a couple of years ago. The ceiling and roof is made up of plasterboard - timbers- celotex - osb - rubber. They key fact for this topic being that the celotex insulation is above the timbers making it a warm roof.
At the back of the dormer's flat roof it meets the old pitched roof, which is a cold roof with the insulation sitting between the joists on top of the ceiling plasterboard.
I was about to top up the old loft insulation when I noticed that the two roofs are open to each other. Because no insulation is above the plasterboard in the flat roof, cold air from the loft in the old cold roof area can just flow into the space above the new ceiling in the dormer, bypassing the celotex insulation. Diagram below.
What's the appropriate way to deal with this situation? I don't want to make a condensation problem by putting insulation in the wrong place.
Thanks in advance!
We had a larger flat roof dormer extension built a couple of years ago. The ceiling and roof is made up of plasterboard - timbers- celotex - osb - rubber. They key fact for this topic being that the celotex insulation is above the timbers making it a warm roof.
At the back of the dormer's flat roof it meets the old pitched roof, which is a cold roof with the insulation sitting between the joists on top of the ceiling plasterboard.
I was about to top up the old loft insulation when I noticed that the two roofs are open to each other. Because no insulation is above the plasterboard in the flat roof, cold air from the loft in the old cold roof area can just flow into the space above the new ceiling in the dormer, bypassing the celotex insulation. Diagram below.
What's the appropriate way to deal with this situation? I don't want to make a condensation problem by putting insulation in the wrong place.
Thanks in advance!
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