Hi

My house needs some lead work at an abutment. The wall is stone (random rubble), so it's undulating rather than flat. Also, the wall is rather banana shaped. As such, I imagine the slates won't sit tight up to the wall and there will in fact be various size gaps between the slates and the wall, and these gaps will expose parts of the soakers beneath. I hope that all makes sense!

In all I've seen and read, flashing - when with soakers - tends to be just vertical. In my head it would make more sense to have an L shaped flashing given what I tried to describe above. If it was just vertical, it would almost encourage water into the gaps on onto the soakers. I appreciate that's what they are there for. But with an L shaped flashing, the horizontal section would direct water away from the gaps at the intersections, and onto the slates.

Just wondered what people's thoughts are on this please? As it's not commonly done like that, I just wanted to check I'm not overlooking something.

Many thanks

Hi @fostertom

No need for a diagram, I understand what you are saying. But I'm talking about the possibility of the flashing being L shaped, not the soakers - which I know need to be L shaped.

Yes, they are your typical old Welsh slates.

I/we will try to get the slates as close as possible, but in some sections the stone may not be flat faced and so will sit a little proud of the pointing. And the wall undulates. On one side the slates are 2 foot long, so when butted up to the undulating wall with sticky-out stone, the abutment will be quite uneven and there are likely to be gaps as a result. That's why I thought to go belts and braces with the cover flashing being not just vertical, but horizontal to cover these gaps and direct water onto the slates.

Many thanks for your reply

Thanks tony. I understand how that's the standard way of doing it. But if more water is getting to the soakers than normal/preferable - on account of the gaps I've described above - could it be that the water travels sideways as well as down? And if so, could it travel sideways enough to reach the side end of the soakers? If that makes sense?!!

Over here the soakers are one long strip placed under the tiles at the end of the rows. The edge under the tiles is turned back on itself (upwards) to stop water flowing over the edge.

I love em

On anything other than brickwork, which has convenient mortar lines at frequent intervals, to use to tuck the flashing into, there's no point in creating a stepped flashing - a single sloping cut just high enough is neater and leaves less exposed lead - wibbly wobbly wall doesn't change that.

One of the plusses of secret gutters, is that that sloping cut can be even lower down the wall - just the requisite height above the gutter floor, which is usually in the rafter-top plane. So you see the tiling/slating unmolested by leadwork, stopping say 50mm away from the wall, then a nice shadow-gap between tile edge and wall, and minimal lead area visible on the wall face. It's especially good when you have say a side-window of a dormer, with sloping cill, which can be brought very low down, just requisite flashing height above the gutter floor - almost to the tile-top plane.

"there's no point in creating a stepped flashing"

One advantage is that it doesn't suffer from thermal expansion related side effects as much as a continuous strip does

Posted By: GreenPaddythen down the wall vertically, then horiz onto the roof timbers, with slates added after

That sounds totally leaky! What's to stop water running down the wall and the vertical flashing face and it's already inside, under the slates and will spread sideways off the lower horizontal face of the 'sort of "Z"'. It would be fine if that lower horizontal face were formed into a secret gutter. However, whatever you do, it shouldn't all be all in one section - need lower piece(s) and an upper piece lapping down over the lower.

I missed that. A rolled-back edge could easily be overcome by wind pressure; a tilting fillet begins to sound like a proper secret gutter, not less than 25mm high I'd say, i.e. secret gutter floor flush with rafter tops or preferably a bit lower than, requires careful rafter planning.

Thanks for all this - it's very much appreciated.

And thanks for the alternative ideas @GreenPaddy and @WillInAberdeen. But I think I'm going to stick with the previous suggestions in the thread.

So here's what I'm aiming for:

- Individual soakers beneath the slates, with 75mm upstands and 150mm horizontals.
- Slate and a halfs for every other slate, instead of using thinner cut slates.
- Flashing in lengths of 1100mm, with 150mm overlaps (so the actual exposed lengths will be 950mm; 4 of which fit the length of the roof perfectly.
- Flashing in upstand only, with NO horizontal pieces on top of the lead. I'll use 150mm width lead for that. So with 25-50mm in the chase, the remainder will be enough to cover the upstand of the soakers. And I won't be stepping the flashing - just straight lines parallel to the roof.

Does that all sound ok?


I think perhaps I was overthinking and over-engineering with my idea to have the Z shaped flashing so that a horizontal section could cover the slates. So I'll do without that, based on what was said above. But for peace of mind I'll use slate and a halfs, and 150mm on the soakers (had originally planned for 100mm). That should keep water from reaching the end of the soakers and creeping in beneath them... Hopefully!

Many thanks

"That should keep water from reaching the end of the soakers and creeping in beneath them..."

If it could do that on a soaker it could do it on a slate.
Underneath a soaker, is a slate

That is what any all flashings are there to prevent (they don’t always succeed)