Insulating a flat roof

14 Nov 2006
Reaction score
United Kingdom
My bathroom has a flat roof. I have removed the old ceiling and would like to install the new ceiling with some sort of insulation. There are 6'' joists supporting the roof, is it possible to fit say 2'' of insulation directly above the new ceiling thus leaving a 4'' void or am I at risk of condensation forming?
Sponsored Links
You can use 4" insulation leaving 2" air gap, if there's no ventilation via soffit area, then best to put some in, screwfix sell the circulation fascia/soffit vents with the hole cutter drill bit. You may also find it easier to use insulation slabs instead of roll type in between ceiling joists. Sliver foil backing plasterboards helps to reflect heat loss and moisture resistance above
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local