Hi

old polycarb conservatory (two external walls, two using existing walls/edge of house), replaced with modern upvc etc. As part of the join to the house there is an L shaped box gutter fitted between house/cons(so tiled house roof drains into box from 2 aspects). We have a leak at one of the join edges – the cons builder is saying not his prob as the issue is the existing house roof felt being degraded/cracked etc(substantiated with photos and house is 50 yrs old and I’ve seen it and I do keep my eye on other roof parts via attic and don’t disagree with the roof felt status report).

Old cons leaked at door and windows but did not leak at house/cons join. There has been a bit of a leak saga during the build – initially built with blown/frozen mortar) so we got a leak into the bedroom (now fixed), then the box gutter leaked and it took 4 visits to fix this, on the last visit they replaced the lowest layer of roofing felt and did more work on box join. Now the box join now appears fixed but we have a new leak in a new place and this is the one that’s being put down to existing felt issues.

Any opinions/suggestions.