How To Insulate Roof Rafters With Celotex

We used kingspan thermapitch tp10 zero odp which is a 100mm thick rigid board.

How to insulate roof rafters with celotex.

Being lightweight they do not impose significant additional loads on existing structures. Install the insulation flush with the bottom of the rafters making sure that it does not fill the entire rafter depth. Ensure that the insulation boards fit tightly between the rafters. There will also be kooltherm k7 pitched roof board between the rafters image credit.

Where the benefits of over rafter insulation want to be enjoyed while still creating a useable room in the roof space it s possible to insulate over and between the rafters. I wish to use celotex 50mm between the rafters 70 x 150mm up to the 2m height. Kingspan with a warm roof the usual process is to split the insulation into two layers. Alternatively battens can be secured to the underside of the.

The saint gobain insulation uk u value calculator gives you instant access to calculating a proposed insulation thickness and product options or giving an indicative calculation on a proposed construction detail. For example if the space beneath the rafters is going to be used for a living area then you will need to insulate the roof rafters. Insulate the flat roof 75mm celotex fixing plasterboards to the cross supports creating a ceiling. Depending on the specifics of the roof it may be possible to fully fill the rafter depth or in most cases leave a 25mm or 50mm air gap between the top face of the insulation and the.

Not insulating between the rafters above this space thus creating a huge air space. Rigid polyisocyanurate pir foam insulation boards from celotex are among the most thermally efficient commonly available insulation materials on the market. Cut the insulation boards to size using a sharp knife or fin toothed saw. Celotex polyisocyanurate pir foam insulation boards are easy to cut and handle.

If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of. Due to the thermal bridging effect of the timbers the overall thickness of insulation used to achieve a low u value is not as efficient as over rafter insulation only.