Rendered over lead flashing.

[LeeDowner]

Hello. I just had the back of my house rendered last week.

There was flaky old paint on the bricks so to save scraping it all off I had 20mm insulation boards fitted followed by an undercoat and then a white rendered finish (pictured)

There's a single story extension with a pitched slate roof which has lead flashing chopped into the brickwork, never had any problems.

The rendering guys put a white plastic bead over the top of that flashing and then rendered onto it so as far as I can see the render and the lead are not touching.

In the first picture with the drainpipe you can see how dark the wall is in the corner, that's just a sand and cement mixture I had put on a few years ago which will now be coming off anyway. The other pictures show how the lead flashing, the plastic bead and the guttering all interact (or don't, as that is the issue!)

I couldn't get my phone in to picture it but it looks like the lead hasn't been moved at all, it disappears behind the plastic bead and I suppose rainwater disappears with it as it did last night.

 

[LeeDowner]

The last picture shows a piece of lead under the tiles but there's nothing to stop rainwater filling up in that corner, doesn't seem to be any kind of sealant between the plastic and the lead so it's obviously going behind the wall.

 

[stevethespreader]

It's always best to go round lead flashing it don't look like a neat job not sure what they was trying to achieve putting a bead over it is it cement render? Think the best person on here to ask is roy c as he's a builder as well

 

[LeeDowner]

I posted this in the roofing forum too as it involves rendering and roofing, there's pictures of the bodge that was done.

The flashing behind it is stepped, suppose that would've been tricky to go around and would've left the sides of the render exposed to water. The plastic bead holds the insulation boards and then it's all covered with the render.

 

[stevethespreader]

I forgot about the boards just thought it was render I've never done that type of boarding on the outside so can't comment much more but you don't make it clear in your post about what your concerns are? Water getting behind the render or flashing?

 

[LeeDowner]

In the second picture I posted you can see down into the little pocket where the white render/plastic bead meets the lead flashing.

There was nothing between them! So rain would run straight behind the render. I think they should've fitted another soaker at the bottom first and then bent it around the new render, running the new soaker into the gutter.

Here's a picture of the bodge he did yesterday....

It's just flash band patched over the top which does plug the gap between flashing and render but the edges of the flash band are exposed and just a matter of time before rainwater fetches it off.

Ooh tradesmen... Bish bash bosh, get paid onto the next.

 

[roy c]

When slating a roof like yours every slate has a "lead soaker"up the abutting wall underneath then starting off with lead soaker under the first slate and stretching over the facia board so the rain runs down the roof and the lead under the first slate kicks it into the gutter.They are usually turned up the wall about 4 inches and every one over laps each slate as they go up the roof.Then a lead cover flashing goes up the wall and over laps the upstand of the soakers.The lead flashing is not made of one piece of lead, it might be four or more sections of flashing and they are over lapped (about 4-6 inches or more) before the flashings have been put on, it it must be decided wether it is "chased" into the wall.That means there must be a chase cut into the wall and the flashings must have a "lip"bent over (I used to bend them over about an inch). After grinding a chase down the wall at the height you want them to go into (Not forgetting the chase has to be double the size of the lead you use as when each lip of the flashing are put into the chase each one over laps the one below).We used to tap them into the wall and make lead wedges to tap into the groove where the lead fits and and knock them in with a thin chisel to knock them home.After they were all in then you use non silicon mastic and run a line of it up the gap where the edges of the flashings are. Any rendering or beads put on the wall starts above mastic joint, so if in future if a slate or slates have to be replaced all you do is fold the lead up and no bother (also having the flashings done in sections it helps to lift them when you need to. It looks like they did the right thing about keeping the height of their work above the flashing but instead of returning their work a bit further down below the gutter line has caused the problem of not letting the water get away as it runs down the roof and gets trapped in that little corner!!! They should of let the gutter run through and dressed lead under the last slate to run the water off into the gutter. I don't think they thought or couldn't think that one out. So get them back and make them cut that bottom right hand side area out so the water coming down that edge goes into the gutter!!! Shouldn't be too hard and that would sort the problem out...One last question did they put new lead down the wall before cladding it? If so you will have problems if you ever need to change a broken slate in that area.P,S. Never use silicon on lead!!!

 

[roy c]

Hope you can understand what I have put up you might have to read it a few times to get the jist of it

 

[stevethespreader]

When slating a roof like yours every slate has a "lead soaker"up the abutting wall underneath then starting off with lead soaker under the first slate and stretching over the facia board so the rain runs down the roof and the lead under the first slate kicks it into the gutter.They are usually turned up the wall about 4 inches and every one over laps each slate as they go up the roof.Then a lead cover flashing goes up the wall and over laps the upstand of the soakers.The lead flashing is not made of one piece of lead, it might be four or more sections of flashing and they are over lapped (about 4-6 inches or more) before the flashings have been put on, it it must be decided wether it is "chased" into the wall.That means there must be a chase cut into the wall and the flashings must have a "lip"bent over (I used to bend them over about an inch). After grinding a chase down the wall at the height you want them to go into (Not forgetting the chase has to be double the size of the lead you use as when each lip of the flashing are put into the chase each one over laps the one below).We used to tap them into the wall and make lead wedges to tap into the groove where the lead fits and and knock them in with a thin chisel to knock them home.After they were all in then you use non silicon mastic and run a line of it up the gap where the edges of the flashings are. Any rendering or beads put on the wall starts above mastic joint, so if in future if a slate or slates have to be replaced all you do is fold the lead up and no bother (also having the flashings done in sections it helps to lift them when you need to. It looks like they did the right thing about keeping the height of their work above the flashing but instead of returning their work a bit further down below the gutter line has caused the problem of not letting the water get away as it runs down the roof and gets trapped in that little corner!!! They should of let the gutter run through and dressed lead under the last slate to run the water off into the gutter. I don't think they thought or couldn't think that one out. So get them back and make them cut that bottom right hand side area out so the water coming down that edge goes into the gutter!!! Shouldn't be too hard and that would sort the problem out...One last question did they put new lead down the wall before cladding it? If so you will have problems if you ever need to change a broken slate in that area.P,S. Never use silicon on lead!!!

Very informative roy nice post

 

[LeeDowner]

Thanks Roy. He's coming back later today.

He said he only does rendering so maybe his roofing knowledge is very basic although rendering does sometimes involve altering bits of roof work so he should know better.

But then the silicone on lead, maybe he doesn't know better or he's trying to fob me off with a bodge.

Anyway I'll ask for money off what I owe him already and put that towards getting a roofer onto it, I don't trust him to put it right.