When moisture has worked its way past the membrane and into the substrate, the wood underneath has to come out. We cut out rotted decking and replace it properly before sealing the roof back up.
The membrane on your roof is just the waterproof layer. Underneath it is a plywood or OSB decking that gives the roof its structure. Once water gets past a failed seal or seam, that decking starts to rot — and a new membrane laid over rotted wood won't hold up.
This is usually the most expensive repair we do, because it means undoing the roof down to the structure. We don't recommend it unless it's actually needed — that's what the inspection is for.
This work has to be done in person. Decking repair requires removing sections of the roof membrane and structure — it cannot be done reliably in the field. Schedule an inspection →
An inspection tells you for sure, before you commit to anything.