cause of damp patch

johnniepk · Posted: Sun Sep 23, 2007 2:22 pm

I have a \\\'marley\\\' tiled roof. A dormer juts out. In the bedroom a damp patch has appeared about a foot back from the join of the dormer and roof. In the loft space there is no sign of water getting in. Outside the flat roof looks fine. However to my suprise I found this strange \\\'valley\\\' thing that goes right from the dormer to the ridge tiles, about an inch across.It has a corrugated piece of material underlapping the tiles, under that is roofing felt.Is this normal roofing work or the answer found by someone who could not make the tiles meet each other? Roof is about 10 years old. I cannot see how the rain is getting in but it is ONLY when it buckets down.I can only assume the \\\'gap\\\' has something to do with it.Could I just tile over this gap or even fill it in with sand and cement?thanks, I shall now try to figure out how to do piccys.!

johnniepk · Posted: Mon Sep 24, 2007 5:24 pm

Having lay down in all the muck up there (previous roofer deemed to leave tons of cement etc lying on rafters!)I can see wood (3x1?)coming out from under the dormer roof into the loft space. Two of these are soaking and dripping onto the ceiling. No sign of it coming down the roof to these so must be coming from the flat roof. I see a small piece of felt on the side has come loose, but this is about 3 feet away.Still trying to do pictures.Thanks

johnniepk · Posted: Mon Sep 24, 2007 5:31 pm

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=flatroof.jpg

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=valley.jpg

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=gap.jpg

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=ridgetiles.jpg

Hope this workd...

greengrass · Posted: Wed Sep 26, 2007 8:07 pm

I've looked at the pictures and I am quite amazed!!!!. I've never seen this before and I've worked on a few rooves [retired] with Redland 49's interlocking tiles which I'm sure that's what they are.

However before getting the gap closed first go to your local planning office with the photo of the gap [3rd posted] and ask if there is any reason for this gap.

If your findinga at the planning office say it should not be there then close the gap.

If you look at tiles on the right hand side of the gap they've been cut the edge that receives the next tile has been cut off. If your ok on a roof, which I assume you are if you took the pictures, then take off one of the cut tiles on the right and one full tile from the left and try fitting the full tile on the right and lock it's left edge under the tile next row up and see if it closes the gap. bear in mind there is no support batten across the gap. If it fits then join them count the rows up and add 5 to the total number [tiles required] you've got two broken ones to replace which might be the cause of the leak.

My guess at the moment is 'Cowboys' who couldn't tile to save their lives, but I might be wrong, they had one working from the left and one from the right came to the middle and hey presto a gap. How do we fill this we can't move the rows they're nailed. So it seems a trip to Wickes while the others were sawing off the battens crossing the gap. At Wicks the cowboy spots the corrogated bitumen sheet and thinks 'An Ideal bodge coming up'............. and it's back to your roof nail in the corrogated sheet bodge done. Because IF this was a proper job and that gap has to be there, although don't know why, that gap would comprise what is called a 'hidden gutter' in grade 6 lead and it has to be done properly with timber risers left and right to support the gutter upstand and on the rafters an under support board all the way to the ridge closing under the ridge tile. Or even made as a narrow 'valley'

And from the decription of removing the muck from the rafters says to me in big letters 'COWBOY'S' pity the Indians didn't get them.

Did you have this roof and dormer done ? If done by previous owner then you might have a case against the firm who surveyed it on your and or building society's behalf and should have picked this up.

johnniepk · Posted: Wed Sep 26, 2007 8:40 pm

Thanks for the reply.A lot to digest.I think I need to reread agin but I think you confirm the gap is a 'oh ooh' what do we do now? fix.

Roofer · Posted: Thu Sep 27, 2007 8:15 am

I disagree with greengrass' assumption that this was done by 'cowboys'. A cowboy could never bed a ridge as neatly and cleanly as that.

I think the tiles are Marley Ludlow Majors and although forming a detail like that in the middle of a roof is highly unusual the actual method used is spot on. The 'corrugated piece of material' under the join is almost certainly a GRP Bonding Gutter and is used when two separate roofs meet.

The only reason I can think of for forming this detail is if your roof is so out of square that the tiles needed to be cut somewhere and rather than do it on the edges of the roof (the verges) the tiler has laid full tiles on the verge and formed this detail above the dormer where it is not visible. Do you have tiles below the dormer? Do they have a join like this as well?

Unfortunately none of this gives a clue to why your rooof is leaking but don't assume that the join is the cause

masona · Posted: Thu Sep 27, 2007 9:06 am

Is the gap on your roof or between you and your neighbour?

johnniepk · Posted: Thu Sep 27, 2007 1:42 pm

There is no gutter at the front end of the dormer, those tiles meet and overlap perfectly.
The gap is almost right in the middle of the dormer to the ridge tiles and not the join between my neighbour and I.
My neighbour had their roof tiled last year and I got on well with the lads doing it and they surely would have spotted it and made comment.

masona · Posted: Fri Sep 28, 2007 9:06 am

Can you take another photo further back so we can see the whole roof?

johnniepk · Posted: Fri Sep 28, 2007 10:46 am

Yes will do later if light enough. From nowhere on the ground can you see this gulley, its hidden by the dormer.

johnniepk · Posted: Fri Sep 28, 2007 10:53 am

My house is a semi built in 1917.

johnniepk · Posted: Fri Sep 28, 2007 4:54 pm

More pictures!! Note the loose felt.Obviously needs fixing back.Is this a clout nail job? Would the felt on the flat roof let water under because it is not 'tight'?

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=mybsack.jpg

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=bsckright.jpg

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=back.jpg

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=loosefelt.jpg

js.roofing · Posted: Fri Sep 28, 2007 8:23 pm

I also disagree with greengrass.
no way would cowboys use a grp bonding gutter, cut the tiles nice and straight, and bed ridge neatly. Wickes would'nt sell this grp valley anyway, it is the correct material for the job, and it is fitted correctly-as roofer pointed out. Irrelevant of weather or not it should or shouldn't be there, the actual problem if you expand the pic of your flat roof, is if you look closely the felt has perished in places, it certainly looks like its seen better days, my money would be on the replacing the flat roof. Why not get a reputable roofer to come and give an opinion.

bikerm4 · Posted: Fri Sep 28, 2007 8:42 pm

The tiles on the left of the grp gutter look to be a couple of inches lower than the ones on the right. seems to me the roofers have lost guage on the laths on the right hand side as they lathted up the sides of the dormer, when they get above the dormer the laths dont meet up so they have fitted the gutter to get over the problem.

johnniepk · Posted: Sat Sep 29, 2007 10:45 am

Thanks This is all very useful and exactly what I need. I will of course take all advice and follow it.
I have been worried the recommendations of a local firm would be very expensive and the more knowledge I have the better I am able to know what is required and hopefully keep the price down.
The felt roof is just on 10 years old, which from what I have read on here is 'getting on a bit'.
Would refelting this need scaffolding?