This roof type will require a breathable membrane like kingspan nilvent to be.
How to install insulation between roof rafters.
Garages built without attics are.
As this requires fitting insulation above the rafters the roof covering will have to be removed in order to fit the insulation.
Fit the cut quinn therm qr insulation boards tightly between the rafters with the quinn therm branded side facing into the building.
Apply insulation between rafters when finishing an attic into a heated room or when building a cathedral ceiling in the home.
Measure the space between the rafters where the insulation will be placed and cut the insulation boards marginally wider than the space to ensure a friction fit upon installation.
Modern u value targets mean installing insulation between rafters only is rarely a viable option.
We would always recommend having a breathable membrane in place between the tiles and the rafters too to allow the roof to breathe.
How to install rafter insulation.
When you use solid insulation board to create a warm loft the key thing to remember is ventilation you must keep a 50mm gap between the roof and the rigid insulation board.
Then blow another layer on top of the roof rafters.
It allows insulation to be installed in a watertight roof either after the roof covering has been fixed on a new build or without disturbing an otherwise sound existing roof covering as part of a renovation.