Hi, i have bought an old house approx 1907 built, it has had the loft converted on it in the 1970s by the previous owner with limited insuation in place.
I'm in the process of renovating the entire house and have removed all of the old plasterboard and insulation.
The rafters are 75mm x 50mm i want to use Celotex or similar insulation but the manufacturers instructions advise that there needs to be an air gap of 50mm minimum. I only have 75mm to play with so this would leave only 25mm for insulation, i am limited to how much insulation i can place under the rafters as the bedroom door will hit the plasterboard.
Is it possible to leave a minimum air gap of 25mm and insulate with Celotex then insulated plasterboard under the rafters to the depth access will allow or is the 50mm air gap an absolute must have?
I'm in the process of renovating the entire house and have removed all of the old plasterboard and insulation.
The rafters are 75mm x 50mm i want to use Celotex or similar insulation but the manufacturers instructions advise that there needs to be an air gap of 50mm minimum. I only have 75mm to play with so this would leave only 25mm for insulation, i am limited to how much insulation i can place under the rafters as the bedroom door will hit the plasterboard.
Is it possible to leave a minimum air gap of 25mm and insulate with Celotex then insulated plasterboard under the rafters to the depth access will allow or is the 50mm air gap an absolute must have?