I was considering spray foam but i ve done some research and it seems the underside of the slate tiles need to breathe to get rid of moisture that would otherwise accumulate in the rafters and cause rot.
Slate roof no insulation.
Roofing felt was introduced primarily to act as a secondary barrier against wind driven snow and rain but its use also causes a reduction in air movement within the roof space particularly if the roofing felt is impervious and this effect is often compounded by the introduction of insulation.
Roof is the original slate from 1930 on boards.
It had no insulation whatsoever between the plaster and the outside roof.
Then you will require insulation that is safe from the elements.
There s no insulation under there currently just the rafters and wood plank sheathing.
The space between the rafters is a bit haphazard because of the age and shape of the roof.
Answered 14th jan 2013 like 2.
Duct work is r4 2 flex off of insulated main fixed duct.
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.
Duct work sitting on the floor.
I am left with from the outside inwards slates nailed onto planks about a foot wide and half inch thick nailed onto the rafters which are about 10 inches by 3 inches.
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.
A well ventilated roof space is good this stops your timbers rotting.
Wet heating coil is fed from a basement boiler.
Gable windows at at each end summer open winter closed.
Foamglas offers complete safety and peace of mind.
If you want to insulate the sloping roof you definitely don t want to install spray foam against the back side of the slates.
Rafters have no insulation under slate.