Leaking roof - help!

[Chris Hill]

Hello,

Hoping for a bit of help with a roof problem I've just become aware of. Any comments gratefully received...

Went up into the loft this morning to do some clearing out (bored with Xmas). Was disturbed to see that some of the roofing felt had started to fall apart in small patches and that there was evidence of damp on some of the rafters, purlins, and other woodwork. In one or two places lumps of felt had come away completely meaning I could actually touch the rear sides of the slates. No idea how long it has been like this as I don't go up there very often, but (touch wood) there has been no evidence of staining or damp on the ceilings below. I live in an exposed part of the North of England, and we've been hit pretty hard by the storms recently, so maybe it hasn't been like this for very long. I've looked at theroof from the outside from ground level, but I can't see any missing or damaged tiles, but then I am looking from a long way away. Have managed to get a roofer/builder to come out on Tuesday 29th, but before he comes I'd like to get a few things straight in my own mind so I've some idea of what is going on:

1) My understading is that the main waterproofing of a roof comes from the tiles, not the felt. Is this right?

2) If 1) is right, then the roofer should be looking at why water has got in rather than just patching up the felt - true?

3) The house is a mid-terrace dating from the 1850s, so the presence of roofing felt means it must have been re-roofed some time in the last few decades? When I say "felt", by the way, the stuff that I've seen this morning seems to have a plastic or similar backing to it.

4) The roofer who is coming to take a look on Tuesday is on the local council Trusted Trader list and is a member of the Chartered Institute of Building. Are either of these any real indicator of quality?

As you can probably tell I don't know a lot about roofs or roofing (although I probably know more now than I did at 9am today!) so any comments or observations would be very welcome.

Thanks...


Chris.

 

[Chris Hill]

Also found these two videos which helped me understand the principle of how a roof "works":

 

[terrypin]

The felt perishes over time, this is nothing more or less than any other roof with the same felt.

The felt cannot be repaired(properly) from the inside.

Felt is purely a secondary barrier in case the first(tile/slate)fails.

Are you sure it's water ingress and not condensation?

 

[Chris Hill]

Thanks Terry, for your reply. I had heard that this stuff doesn't last forever and that the only way to replace it is to re-roof the whole thing (£££). Had also read that the purpose of felt is not primarily to prevent water ingress, so thanks again for confirming that.

Is it condensation? Well, that is an interesting question and I cannot say definitely "no". After all, it has been ridiculously damp for the time of year. On the other hand, if it is condensation then there is a hell of a lot of it! On the other, other hand, the loft space is very draughty, which I understand is a good thing and helps to dispel condensation. So I think which I'm trying to say is "Haven't a clue, mate". I'm hoping that the roofer will get up on his ladder, find some knackered slates and that'll be the end of it. If only life could be that simple!

 

[terrypin]

9 times out of 10 it's obvious(broken tile/slate)and an easy repair.