Leaking Roof Dormer Flashing Advice

[ant192]

Hi all, first time poster but long time beneficiary of the advice given on here.
My roof has a leak which I have narrowed down to being an issue with the lead flashing between the pitched room and dormer cheek. I have been let down by three roofers now and been waiting 2 months, so considering tackling this myself.
Interested to get opinion on where you would start with this and what the best course of action is. Thanks

 

[ant192]

To add, using a hose I have confirmed the leak to be in the area with the green circle

 

[datarebal]

lift the lead up and check tiles

 

[feynman]

This is a coincidence - I have a very similar issue.

Yours looks to me as if it has been incorrectly applied; the flashing should turn vertically upwards behind the vertical tiles for a few inches otherwise the rainwater will simply drain down the gap between those and the pitched roof. The flashing obviously should form a gutter to channel the water down and away but not allow it to run down the join between the vertical and roof tiles and enter the roof inside. Hard to make this out from the photo.

As suggested, you might have to remove some of the vertical tiles to see if the flashing has cracks in the corner, or does not turn up behind the tiles.

My roof - very similar to yours, except no tiles on the vertical wall - has "lead" flashing correctly cut, jointed and mortared into the brickwork. However, I was up there yesterday and the flashing has cracked completely through in about four or five places where the flashing has been bent to follow the profile of the roof tiles. There are gaps a couple of millimetres wide - allowing rain to flow down into the roof and behind the plasterboard wall, wetting the floor and then soaking the carpet from underneath.

Looking closely at the flashing, it looks like lead, but I don't think it is - it does not bend or feel like lead, and there are places where the lead seems to have weathered off revealing what looks like copper underneath.

And the cracking through - I have not seen lead crack like that. Is lead plated copper flashing an actual thing?

 

[Deluks]

That drainpipe further up should be extended into the gutter below, in heavy rain that will be chucking loads of water down onto your flashing.

Second bloke: you might have zinc or galvanised (your copper could be rust)

 

[bbjc]

Out of interest how would you extend it without it moving with the weather bud.

No where to really clip it to. Could glue it but big ask to hold it in place. Is there a better way.

 

[Deluks]

Don't know how to secure it, (maybe a section of metal banding tucked under the tiles and screwed to a the nearest batten?), but you'd need to replace the shoe with an elbow and adjust to suit the roof angle. Self tapping screw into each joint so it doesn't fall apart.

 

[catlad]

As Deluxs
Move the down pipe and you might find the problem disappears!
bbjc I have fashioned plenty of round down pipe brackets out of 10mm coper pipe and then attached them to batons. A bit of black bitumin paint after.

 

[bbjc]

Cheers catlad. Just seen this much appreciated tho. Will give it a go for the next time.

 

[tell80]

OP,
You have (bossed) profiled lead cover flashing over profiled tiles - thats correct.
However, does the cover flashing have a min 75mm upstand that goes up & under the wall hung plain tiles?
Also do the overlaps between lengths of cover flashing overlap at, say, 100mm - 150mm?

We dont know if the RWP is picking up a gutter and a dormer valley or is simply an outlet for a gutter only?
If its for a gutter only then the gutter falls and outlet can be re-arranged to drop near the front of the dormer - that re-arrangement would eliminate the rainwater flow down the cover flashing.

You could also look into pipe fixing clips for vertical hung tiles eg. Dreadnaught Tiles etc.
Using clips you could run the RWP along the cheek of the dormer above the cover flashing.

 

[Nige F]

This is a coincidence - I have a very similar issue

My roof - very similar to yours, except no tiles on the vertical wall - has "lead" flashing correctly cut, jointed and mortared into the brickwork. However, I was up there yesterday and the flashing has cracked completely through in about four or five places where the flashing has been bent to follow the profile of the roof tiles. There are gaps a couple of millimetres wide - allowing rain to flow down into the roof and behind the plasterboard wall, wetting the floor and then soaking the carpet from underneath.

Looking closely at the flashing, it looks like lead, but I don't think it is - it does not bend or feel like lead, and there are places where the lead seems to have weathered off revealing what looks like copper underneath.

And the cracking through - I have not seen lead crack like that. Is lead plated copper flashing an actual thing?

Can you post a new thread with a picture of the cracks and the strange weathered lead ?

 

[feynman]

I would, but it was a bit of a palaver ratchet-strapping three ladders together to get up there, and I have taken that all apart now. If I remember I will take a pic of some other flashing that looks similar from ground level, and I will also scratch the surface a bit to see what metal it actually is. Looks like lead, but doesn't feel or bend like lead. Don't think it is zinc.

 

[tell80]

feynman,
why not move your post to a new thread - ask the mods?

 

[catlad]

Cheers catlad. Just seen this much appreciated tho. Will give it a go for the next time.

Forgot to add, if you are bending small copper pipe to fashion a bracket for a round down pipe, you will need to thread some electric cable or similar through the pipe to stop it kinking when bending it.