What type of roof is this? plus a leak in valley

[Mikefromlondon]

I have a problem of water leak when it rains, and I got up on the roof to see what was going on,
and I can see where the problem is, and logically a valley cannot be formed at this joint because of the nature of the "plane" of two roofs meeting, even though it has a shallow valley made of lead sheet, it cannot cope with heavy rain so spills over and water then lands under the tiles of the side roof, from where it has been leaking through poor condition of the felt.

Tiles of the roof are in very good condition, could last another 20 to 30 years, beyond my life, so what can be done to remedy the situation?

will I have to get a roofer to take down tiles and relay a new roofing felt and re-construct another valley a little more deep if it can be done though I can't see how they can make this valley more deep due to the nature of the planes the two roofs meet at.

any other suggestions? like can it be cemented so that water from main roof can only run on top of the side roof as a temporary fix.

Please see a small model i made to demonstrate how the two roofs meet, and so i am not sure what this configuration is known as, all help will be appreciated much, Thanks in advance

 

[catlad]

Does the existing lead valley have a welt at the edge to stop the water from overshooting?
another option if you are using tiles is a grp dry valley with a raised centre.

 

[Mikefromlondon]

Thanks for your reply, yes it seems to have this welt about an inch and not sharply angled so the water fall from the main roof just climbs straight across this welt and ends up under the side roof tiles, I guess it has always been like that since the roof was retiled god knows by who, we bought that house in 2001, and only during the last year or so some water has found its way through the ceiling and is dripping down from holes it made in the ceiling. I guess the under felt has gone rotten!

I went up this side roof which is shallow and so felt fairly comfortable, and wanted to check if any tiles were dislodged or cracked, but none were, and I could see the problem is the valley, I turned the welt inwards to create a sharper angle so that water would curl back, but this doesn't help in torrential rain, the rain water flow or the water fall from the main roof is really fast flowing, due to steepness of main roof, overcomes this welt. I did lift some tiles up from the side roof and tried to raise the welt as high as I can before replacing the tile down again, but the weight of the tile pushes the welt down again, I also saw the condition of the felt is really bad, it will need replacing, it has many perforations in it.

Do the roofing companies undertake re-felting work and reuse the same old tiles or would they not be interested in such roof repairs and so they might as well quote for a new roof?

 

[^woody^]

It's a valley, like any other valley, and if it leaks it needs a repair or has not been constructed properly with tilting filets and mortar.

 

[Mikefromlondon]

Thanks woody, I could not see any fillets or mortar, just a bit of cement, under the gaps of the side roof tiles, most of which has cracked away, the valley is hand constructed with badly formed welt, (If I understand correctly the welt means the edge of the leaded valley, is not smooth and in straight line and runs like zig zag railway lines due to expansion from heat and no gaps in those rails. The height of this welt (wall) is no higher than about an inch.

So really I would need a proper roofing company to look at it and quote for a new felt, a new valley and so on.

 

[Mikefromlondon]

Second question, my wife owns this top floor flat, and someone else owns the ground floor flat, I understand the roof work is a joint responsibility, so i should be able to get the owner of the flat below to chip in on cost of repairs, or new felt, and I also wanted to know if such work is covered by building insurance? (although i doubt if wear and tear is covered under any building insurance policy)

 

[Mikefromlondon]

I have booked a local roofing company to come over and provide me with a report and quote for a new valley and under felt and see what the other owner downstairs says about it.

 

[catlad]

Well mike what you are describing is the reason you don't construct like that
are you sure its not just a dodgy extension?

 

[Mikefromlondon]

No Catlad, this is the old 1930s construction, and upper level that she owns, used to be one time a 3 bed house and then got converted to two seperate 2 bedroom flats. However the roof is not original as original roofs were all slates and now uses conc tiles, and I suppose roofers used substandard cheaper felt.

 

[datarebal]

there is no reason why this cannot work, provided the lead is wide enough with tilting fillets and the standard welted edge.

 

[Mikefromlondon]

Assuming the valley could be fixed, with a proper channel with welted edges, and cementing any gaps under the tiles, this should stop torrential rain water seeping across overcoming the welted edges and penetrate under the side roof tiles, what do you say about the rotten felt under? would it not need replacing?

Wouldn't replacing the felt mean taking down all the tiles and rebuilding the roof all over requiring scaffolding and what not, so the cost would be almost like the cost of a new roof.