Hi
Bit of advice and guidance needed - if you don't mind.
The top floor of our 19th Century house is freezing cold. It has a cathedral ceiling and a slate tiled roof. Having inspected the insulation and roof from within the house - i.e. removed a bit of the spray foam insulation; it would appear that someone has applied insulation spray foam directly on the slate tiles - but has left the underside of the rafters exposed. Currently, the roof does not leak.
To increase the warmth of the room, I have thought about overboarding the spray foam insulation with additional board insulation, i.e. fixing it to the exposed rafters. It seems such action could end in disaster, i.e. build of moisture leading to rotting timbers, resulting in needing new roof timbers - in other words a whole new roof. Is this true or have I misunderstood overboarding spray foam insulation?
If I'm correct, i.e. overboarding spray insulation is a recipe for disaster, then I guess the task ahead of me is to remove all of the spray foam insulation, remove roof slates, fit sark, fit batons and re-fix slates. Then insulate room by fixing insulation boards between rafters. Is this correct?
Thanks