I'm using scissor trusses to create a vaulted ceiling in a new bedroom im building above garage.
The drawings detail 150mm celotex between 1st floor joists and 50mm under the joists. This seperates the garage from bedroom.
The original plans were for a standard ceiling, but I've managed to convince the BCO to let me use scissor trusses..... ie the original drawings don't deal with the insulation detail for a vaulted ceiling.
Do you think 100mm celotex between rafters and 50 mm under them followed by 12.5mm foil backed plasterboard and skim would suffice? Do I need to leave 50mm airgap between the celotex and the roofing membrane?
The drawings detail 150mm celotex between 1st floor joists and 50mm under the joists. This seperates the garage from bedroom.
The original plans were for a standard ceiling, but I've managed to convince the BCO to let me use scissor trusses..... ie the original drawings don't deal with the insulation detail for a vaulted ceiling.
Do you think 100mm celotex between rafters and 50 mm under them followed by 12.5mm foil backed plasterboard and skim would suffice? Do I need to leave 50mm airgap between the celotex and the roofing membrane?