We've recently had our roof re-felted with a breathable membrane and slated. Upon completion we discovered a significant quantity of debris trapped between the slate and the new roofing felt in a couple of places. This is mostly around the valley area on a hipped roof, so I've come to the conclusion that the roofer has been sitting on the ridge, cutting the slates to shape, and any debris has been falling into the gap between the felt and the slate, where it has collected where it has met the rafters. There are a few places where the debris is at least a few centimetres thick.

I am concerned that over time it will gather moisture (condensation?) and rot through the felt (in places the felt is under such strain that it has already ripped slightly).

Is this normal?

Should I leave it as is, or demand that it is sorted out?

I'm concerned that fixing the issue would result in more problems due to having to lift slates/cut the felt.

Any suggestions most welcome! Thanks in advance.

You could do with getting an independent survey to back you up on this as I too think you may need to have the job completely re-done. The felt should not be tight, and it should definitely not have any holes in it. Slate shards are sharp and will work their way through the felt so he should have been careful to keep them off the felt and it makes me wonder what else they may have done wrong.

Thanks very much for your replies on this. Not the answers I was hoping for, but worth knowing

A few comments:

thescruff wrote on Jan 3^rd, 2014, 2:00pm:

Unfortunately, yes, I have paid already

woodsmith wrote on Jan 4^th, 2014, 8:42am:

To clarify, the felt isn't pulled particularly tight. Where I said that it was "under such strain that it has already ripped slightly" I was referring to the places where the debris had collected. Sorry I wasn't clear initially.

There is the odd place where nails (I assume from battens?) have gone through the felt, but I assumed that the odd nail here and there shouldn't be too much of an issue - there was no felt on the roof before and it didn't leak. Am I missing something with this?

woodsmith wrote on Jan 4^th, 2014, 8:42am:

TIMBA-WOLF wrote on Jan 4^th, 2014, 9:46pm:

By independent survey, who do you think should do this? Do you mean pay(?) an independent roofer to have a look, or is there some other building standards organisation that would be better?

I have asked our building inspector (building regs) what he thinks to the issue, and he said that although the debris shouldn't be there, it shouldn't be too much of an issue, and if it was his house he'd just forget about it. However, our building inspector has been rather.. relaxed.. about certain other things, so I just wanted a second opinion.

Thanks again all.

EDIT: Just another thought, even if the entire roof does need need re-doing, I assume I can still continue to fit PUR/PIR board and plasterboard the interior. Apologies for the rookie question(s)!