Sealing Lead Flashing to Concrete Roof Tile
Discussion
The recent heavy rain and wind has resulted in a damp patch on the ceiling in the garage. I can see that water is leaking in at the interface of the house wall to the pitched carport roof. The end joist that is fixed to the wall is wet.
Just over a year ago the house was re-rendered and at that time new lead flashing was installed. The wall interface has the lead fitted into and behind the render. The carport roof is pitched at roughly 10-15 degrees, running at 90 degrees to the wall and is the old school concrete interlocking tiles with the lead pressed against the tiles with mortar filling the small triangular gaps as the leads steps down each tile.
As far as I can see there is only two ways in which the water is getting passed the flashing:
1. Wicking upwards behind the render bead then up and over the lead and running down the back.
2. Getting blown and/or running under the lead at its interface to the tile. The width of the horizontal section of lead is only about 60mm which doesn't seem a lot.
So any suggestions on the best way to seal the lead to the tiles?
I have picked up a tube of lead sealant from screwfix this morning and also have some Blackjack liquid DPM however both of these feel like more of a bodge rather than a fix.
Just over a year ago the house was re-rendered and at that time new lead flashing was installed. The wall interface has the lead fitted into and behind the render. The carport roof is pitched at roughly 10-15 degrees, running at 90 degrees to the wall and is the old school concrete interlocking tiles with the lead pressed against the tiles with mortar filling the small triangular gaps as the leads steps down each tile.
As far as I can see there is only two ways in which the water is getting passed the flashing:
1. Wicking upwards behind the render bead then up and over the lead and running down the back.
2. Getting blown and/or running under the lead at its interface to the tile. The width of the horizontal section of lead is only about 60mm which doesn't seem a lot.
So any suggestions on the best way to seal the lead to the tiles?
I have picked up a tube of lead sealant from screwfix this morning and also have some Blackjack liquid DPM however both of these feel like more of a bodge rather than a fix.
Edited by K is King on Tuesday 1st October 10:49
From what you’ve said it’s bodge time I’m afraid. The lead that sits on the roof tiles should be 150mm at a bare minimum NOT 60mm! Also the lead should be dressed down to follow the contours of the tile, not pointed up with mortar. Ideally it wants new lead up behind the render and a decent lap on the tiles but I’m guessing disturbing the render is not an option. For a better class of bodge than painting blackjack on, pry up, the existing lead as much as possible and slide in some of this Lead free flashing, try and turn it up the wall as much as possible. This product is ‘reasonably’ malleable to follow the contours of the tile and will stick down to prevent wind uplift: it’s also a bit more diy friendly than lead.
wolfracesonic said:
From what you’ve said it’s bodge time I’m afraid. The lead that sits on the roof tiles should be 150mm at a bare minimum NOT 60mm! Also the lead should be dressed down to follow the contours of the tile, not pointed up with mortar. Ideally it wants new lead up behind the render and a decent lap on the tiles but I’m guessing disturbing the render is not an option. For a better class of bodge than painting blackjack on, pry up, the existing lead as much as possible and slide in some of this Lead free flashing, try and turn it up the wall as much as possible. This product is ‘reasonably’ malleable to follow the contours of the tile and will stick down to prevent wind uplift: it’s also a bit more diy friendly than lead.
I do also have a roll of the 150mm lead that was left over from when it was originally installed so I could as you say pry up the existing lead and slide this underneath with a small turn up against the wall. I assume I would then need to run some of the lead sealer between the two layers of lead to seal that interface and then hope that the extended run of flashing is sufficient to prevent water getting underneath........still got the issue of dressing down the lead to follow the contours.....Aluminati said:
Make a lead soaker and run it under the tile. Pic would help.
I think this is going to be the best course of action. Having had a better look at how the roof meets the wall its clear there arn't any soakers present and the whole thing is relying on the overlap of the lead flashing on top of the tiles.Seems straight forward enough to have a go myself.
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