Foam sprayed directly onto roof felt with no ventilation gap
Why it happens here
This is the single most common mistake in Southwark's Victorian terraces. Foam goes straight onto the felt, blocking airflow, and condensation builds up behind it. Within a few years the timbers are wet and rot starts.
Our approach
We remove the foam, check the timbers for rot, and make sure the roof can breathe again before anything new goes in. If a ventilation gap is missing, we tell you and explain what needs to change.