Tue, 19 Dec 2023 08:31:15 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301761#Comment_301761 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301761#Comment_301761 Fri, 02 Jun 2023 11:21:01 +0100 greenfinger
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]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301763#Comment_301763 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301763#Comment_301763 Fri, 02 Jun 2023 13:54:20 +0100 fostertom
You say 'slates' - confirm you mean thin flat double-lapped? Can't they be cut to fit say 15mm clear of the undulating wall face?

Each soaker is the length of the hidden part of each slate - i.e. over half of each slate's length. Its horizontal bit sits on top of its slate and its vertical bit upstands against the wall, all draining downward over the next soaker-covered slate below. So the slates are visible right up to the wall, no visible lead covering over them (except where hidden under the next slate up). A separate long (edit - delete *soaker*) flashing turns down over the series of upstands.

Anyone got a diagram handy?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301765#Comment_301765 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301765#Comment_301765 Fri, 02 Jun 2023 14:36:31 +0100 greenfinger
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]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301768#Comment_301768 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301768#Comment_301768 Fri, 02 Jun 2023 16:21:16 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301770#Comment_301770 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301770#Comment_301770 Fri, 02 Jun 2023 16:34:57 +0100 greenfinger http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301771#Comment_301771 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301771#Comment_301771 Fri, 02 Jun 2023 17:06:29 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301775#Comment_301775 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301775#Comment_301775 Fri, 02 Jun 2023 20:35:45 +0100 Peter_in_Hungary http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301777#Comment_301777 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301777#Comment_301777 Fri, 02 Jun 2023 21:42:33 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301778#Comment_301778 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301778#Comment_301778 Fri, 02 Jun 2023 22:10:31 +0100 fostertom http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301779#Comment_301779 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301779#Comment_301779 Sat, 03 Jun 2023 05:58:25 +0100 cjard
"but I'm talking about the flashing being L shaped"

It won't help, unless you make it super wide and generally flashing that splurges over roof covering like that looks a mess

---

If it helps, in your mind, think of soakers as "slates that bend". Each soaker sheds water onto the slate below it, just like each slate does

See page 15 of https://www.calderlead.co.uk/uploads/documentsearch/id4/Calder-GTGLW-210213.pdf

Consider using a grinder to profile your slates to your wibbly wobbly wall, soakers underneath to requisite width. Due to the unevenness of the wall, you might prefer an individually stepped flashing work up rather than a long sheet with triangles cut out]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301780#Comment_301780 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301780#Comment_301780 Sat, 03 Jun 2023 10:01:39 +0100 fostertom
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.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301798#Comment_301798 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301798#Comment_301798 Sat, 03 Jun 2023 17:39:21 +0100 tony http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301800#Comment_301800 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301800#Comment_301800 Sat, 03 Jun 2023 20:35:36 +0100 cjard
One advantage is that it doesn't suffer from thermal expansion related side effects as much as a continuous strip does]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301805#Comment_301805 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301805#Comment_301805 Sun, 04 Jun 2023 11:24:03 +0100 GreenPaddy
- continuous cut into the random stone, say 75mm above the finished slate line, about 10-15mm high cut and about 50mm deep.
- lead flashing which is sort of "Z" shaped, inserts into the stone cut slot, then down the wall vertically, then horiz onto the roof timbers, with slates added after.
- the lead would normally be say 1200mm long (get 5 from a 6m roll). There are guidance docs about lead length max runs for expansion and tearing.
- the edge of the lead under the slates is either rolled back on itself, or has a tilting fillet.
- folded lead off-cuts to wedge the lead into the cut stone slot. A filler of your choice to close the cut slot above the lead. I use lead mate for ease, but I'm sure a cunning lime mix with linseed oil might be suggested by others (I only use that around windows.

Def would not do soakers in a random stone wall. Not sure what the issue is with seeing the horiz part of the flashing, in the gap between slate edge and vert wall. It will vary following the randomness of the stone. Pre-bend the lead into the "Z" shape before fitting, so get nice crisp corners, which contrasts the stone visually. Choose the point where the stone sticks out furthest, and set that as the line for the top edge of the first lead fold.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301807#Comment_301807 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301807#Comment_301807 Sun, 04 Jun 2023 11:54:18 +0100 fostertom Posted By: GreenPaddythen down the wall vertically, then horiz onto the roof timbers, with slates added afterThat 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.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301809#Comment_301809 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301809#Comment_301809 Sun, 04 Jun 2023 12:34:51 +0100 djh Posted By: fostertomwill 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.He did say the edge should be rolled back to form a lip, presumably to stop run-off.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301812#Comment_301812 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301812#Comment_301812 Sun, 04 Jun 2023 13:06:00 +0100 fostertom http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301813#Comment_301813 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301813#Comment_301813 Sun, 04 Jun 2023 13:14:07 +0100 WillInAberdeen
Leadwork was reserved for only the highest status buildings with straight faced masonry.

(Image from random building on street view, not my slates!)]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301840#Comment_301840 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301840#Comment_301840 Tue, 06 Jun 2023 12:29:11 +0100 greenfinger
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]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301844#Comment_301844 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301844#Comment_301844 Tue, 06 Jun 2023 13:07:45 +0100 fostertom http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301938#Comment_301938 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301938#Comment_301938 Sat, 10 Jun 2023 20:26:34 +0100 cjard
If it could do that on a soaker it could do it on a slate.
Underneath a soaker, is a slate]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301942#Comment_301942 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301942#Comment_301942 Sat, 10 Jun 2023 22:20:59 +0100 greenfinger
My original idea of the Z shaped flashing was to add another layer of defence to the above scenario by preventing most of the water getting to the soakers in the first place.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301950#Comment_301950 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17853&Focus=301950#Comment_301950 Sun, 11 Jun 2023 08:22:37 +0100 tony