Roof rot from trapped moisture
Why it happens here
Foam sprayed directly onto roof felt or tiles seals the roof space and stops it breathing. In West Croydon's wet winters, moisture condenses behind the foam and soaks into battens and rafters. By the time it shows as a ceiling stain, the timber underneath is often already soft.
Our approach
We remove the foam in sections, check every rafter with a moisture meter, and treat or replace anything that has started to decay. A vapour barrier and proper ventilation go back in so the roof can dry out and stay dry.