Trapped moisture causing roof timber rot
Why it happens here
Spray foam seals the roof, preventing air circulation. In Chelston's older slate roofs, this traps condensation against the rafters. Over time, the timber stays wet and rot sets in. The problem is worse on north-facing roofs that get less sun.
Our approach
We remove the foam, dry the timbers, and treat any rot with a fungicidal treatment. We then check the ventilation and recommend breathable insulation that allows the roof to breathe. We provide a report so you can show your surveyor or lender.