Im building a timber chalet
Roof will be uni pitch pent roof at 5 degrees
Im layinng metal roofing sheets on top of 12 mm ply on top of 170 mm joists
Plasterboard on bottom of koists
100 mm kingspan insulation on top of plasterboard
Do I need an air flow over the top of the insulation
This could be a problem as I have noggings running acroos the support timbers
Thx