How To Insulate An Old Slate Roof

Answered 14th jan 2013 like 2.

How to insulate an old slate roof.

With an assumed pre existing u value of 2 23w m the best options are as follows. To insulate the roof itself you either use spray foam or retrofit with it with rigid foam board. The best way is to insulate the attic floor. If you want to avoid internal changes you can do so by insulating externally.

U value 0 38w m. Check the depth between your trusses and the slates then install the correct thickness of kingspan in the gaps allowing for a 25mm air gap between the kingspan and the slates. An advantage of spray foam is it s quick whereas foam board needs to be cut and measured which can be a chore. A well ventilated roof space is good this stops your timbers rotting.

Plasterboard 50mm pur insulation in 50mm timber stud with 50mm vented cavity to the existing wall. You would first have to create a vent channel under the slates by installing 1x1 sticks at the top of each rafter bay followed by stiff material like rigid foam or plywood. The materials used to insulate under the roof include batts of mineral or glass wool insulation held in place by battens of wood attached to and across the rafters. With a warm roof the usual process is to split the insulation into two layers.