Leaking after new roof (about a year old)

[Nozzle]

Evening all,
I have spotted a leak in the roof near a chimney breast; the roof was entirely replaced about a year ago as a part of an extension project (incorporating raising by about 4" so new and old roof heights match). The builder has been over and seen the job, a whilst it was dried when he saw it, it did suggest one of two places how the water might be getting in, and what he was going to do to solve it. All credit to him for coming back and offering a solution. The basis for my post is to put the question out there to roofers to find out what is the very best way of solving this so it doesn't leak (the builder is a builder, not a roofer, if you get my gist?).

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• Nozzle
• 19 Nov 2013
• 1

Image shows what was an existing dormer that had been converted from a flat roof to pitched - hence why it is so close to a chimney with insufficient space for a guttering that goes all the way back to the valley/main roof.

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• Nozzle
• 19 Nov 2013
• 1

Shows a close up of the interface between the chimney and the roof, with what could be "excessive" flashing, but is it correctly seated/sealed against the chimney?

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• Nozzle
• 19 Nov 2013
• 1

Shows a different view, and the problem with the pitched roof and lack of space to have a gutter all the way back

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• Nozzle
• 19 Nov 2013
• 1

Shows the trusses that are damp/were wet - there's evidence that both were wet, but when I saw it only the middle one of these three in the photo was wet - this is the one that runs right next to the chimney, which is just off the photo to the right.

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• Nozzle
• 19 Nov 2013
• 1

This photo has the chimney to the right and is looking upwards towards the ridge. To the left is the dormer, both of the trusses are original part of the house. Ahead of the photographer is just the rear-side of the internal dwarf walls.

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• Nozzle
• 19 Nov 2013
• 1

this image shows the old dormer and roof, just for reference really.

The builder is suggesting they construct some sort of leaded valley in there under the tiles across to to the chimney side, though I'm not sure how this will finish front and rear, i.e if the water will just cascade off onto roof or be managed some better way.

So my question to the roofers out there: how would you re-do this to make it better long-term? Many thanks.

Nozzle

 

[freddiemercurystwin]

On your second photo the flashing doesn't look like its even been cut into the brickwork, it looks like its just resting there. Or is there an existing flashing underneath that is flashed in?

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• freddiemercurystwin
• 19 Nov 2013
• 1

And what's going on above the dormer tiles where it meets the chimney, is there actually a gap? And where is that downpipe?

 

[Nozzle]

Ah, that's probably half the problem then, if the flashing is supposed to be cut into the brickwork. I'm no roofer or builder so until you pointed it out I didn't know that's how it should be done. I'm not sure if it is cut in anywhere around the chimney, I'll check. Access to that side is difficult as the dormer side is right in the way. Should they be raking out the mortar at that level, bending the lead in and re-pointing?

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• Nozzle
• 19 Nov 2013
• 1

This is the only image I have of how the tiles are cut, they have been shortened a little from a full length one, and there is no space for any guttering below them, so any run off just falls between the gap that is left over and onto the main roof. (As I can see it, there's no alternative to this). I do have the downpipe section, it fell off and I intend to refit with a bracket or two.

 

[catlad]

It would have been better to drop the chimney and put a stainless steel terminal on flexable liner for your gas fire.

 

[palaceray]

Your builder is right, you need to strip out the first 2 courses of tiles from the side by the chimney and form a lead box gutter , At the front the lead gutter would dress into the plastic gutter and at the rear it would discharge over a lead cheek on to the roof and chimney gutter.

The lead back gutter behind the chimney should be discharging the water to the side away from the dormer,

Generally it looks like a nice job.

The lead work will need to be done by a proper leadworker who can lead burn.

 

[Nozzle]

It would have been better to drop the chimney and put a stainless steel terminal on flexable liner for your gas fire.

The house already has another matching chimney, so to knock it down would be a shame... not only that, it's a wood burner (now fitted with liner and terminal unlike on that photo) so having it vent right next to a window might be seen as a school boy error.

That said, would sure have solved a problem or two to get rid of it!

Nozzle

 

[Nozzle]

Your builder is right, you need to strip out the first 2 courses of tiles from the side by the chimney and form a lead box gutter , At the front the lead gutter would dress into the plastic gutter and at the rear it would discharge over a lead cheek on to the roof and chimney gutter.

The lead back gutter behind the chimney should be discharging the water to the side away from the dormer,

Generally it looks like a nice job.

The lead work will need to be done by a proper leadworker who can lead burn.

Thanks for this info, I guess when you say strip out the first two courses and form a lead box... you intend that none of the tiles once stripped out are replaced on top of the box? I don't think either of them are proper leadworkers, but they are pretty handy guys nevertheless. Do you have an image (or maybe a stock image from google) of what this should look like? Or what search term should I use, is there a trade name for it?

Nozzle

 

[palaceray]

The bog gutter should have a flat sole of approx. 150mm an upstamd up the brickworkof 100 mm minimum and cover flashing chased into a brick course. On the roof side it should extend a minimum 0f 250mm up the roof slope on a ply board and the tiles are replaced ending aprox 75mm up from the sole.

If you go to Calder Lead site you should find pictures and drawings.

 

[Nozzle]

Thanks for the responses everyone, I think they came over today and did some rectification, but because good old winter is on the way I can't see for toffee. Hopefully I can post a meaningful update tomorrow.

Nozzle

 

[Nozzle]

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• Nozzle
• 23 Nov 2013
• 1

Well, today I went on a little trip to the roof, yessiree.

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• Nozzle
• 23 Nov 2013
• 1

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• Nozzle
• 23 Nov 2013
• 1

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• Nozzle
• 23 Nov 2013
• 1

This is the repair made, looking from being sat on top of the ridge of the dormer window to side of chimney. It's not exactly going to stop the water that is already running down the side of the chimney, but at least all the water that is collected from the tiles will get directed elsewhere

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• Nozzle
• 23 Nov 2013
• 1

The other side looks like a neater job.

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• Nozzle
• 23 Nov 2013
• 1

While I was up there I noticed this, in the foreground is the pitch of the dormer or which I'm sat on the ridge, the middle ground has one of the glassfibre valleys. There's a lot of cracking in the mortar everywhere, I assume this is to be expected. What I didn't expect to see was moss/slime/water coming OUT of one of the cracks?!? There is no sign of leakage inside the house, I hope it's not a sign of things to come.

Nozzle

 

[palaceray]

Good luck with the repair.

He certainly has not formed a box gutter and I can only see future leaks occurring around that area

 

[Nozzle]

Oh dear! Perhaps I should think twice about employing them for another part of an extension that is planned.

Nozzle

 

[freddiemercurystwin]

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• Nozzle
• 23 Nov 2013
• 1

Holy Cow that flashing is just resting against the brickwork isn't it?

 

[Nozzle]

yes, it looks that way! Shame really, the guys did a reasonable job everywhere else and were to budget. Looking over the other photos of the roof on this thread, how would you rate the roof job?

Nozzle

 

[shane12345]

They should give up with lead work! The rest of it seems ok.


That green stain in the lead valley looks like its to do with the water struggling to get out due to that bump / poorly dressed bit creating a channel.