Triassic Posted February 23, 2019 Share Posted February 23, 2019 (edited) I have a single story roof section that abuts a gable wall. The roof with by covered with slates and the gable wall covered with render board and K Render. The question is, what sort of detailing is required at the junction of the wall and the slates to ensure rainwater running down the rendered boards is channelled away down the slate roof? Edited February 23, 2019 by Triassic Link to comment Share on other sites More sharing options...
makie Posted February 23, 2019 Share Posted February 23, 2019 I've used lead, GRP or zinc whenever I have done it Link to comment Share on other sites More sharing options...
Triassic Posted February 23, 2019 Author Share Posted February 23, 2019 To which element did you fasten it, the wall as shown above, or did you fasten it to the render board, if so now? Link to comment Share on other sites More sharing options...
Cpd Posted February 23, 2019 Share Posted February 23, 2019 I have not done this on a modern build...... but I used lead. I made lead gullies and lapped them into a cut line on the stone wall. I must say that I am not very pleased with the gullies as they can get leaves and moss stuck in them and the water can track back onto the roof membrane. was I doing it again I would use soakers. So to answer your question (non expert) i would use high quality (probably not lead) soakers and attach them to the wall and then Use some sort of cover strip that you render down to to get a clean crisp edge. Your fixing points are all covered and sealed and it will look great. I look forward to hearing how it’s “properly done “ ! Link to comment Share on other sites More sharing options...
dpmiller Posted February 23, 2019 Share Posted February 23, 2019 I'm just in the process of doing this, and used an aluminium soaker http://www.kytun.com/p/continuous-aluminium-soaker-24m-blue_black/c14bb just need to stop the battens a bit short for it. Link to comment Share on other sites More sharing options...
PeterW Posted February 23, 2019 Share Posted February 23, 2019 You can create a hidden valley with lead and then lap this up behind the render board. As @Cpd says though, they can get blocked so its best to leave them where they can be cleaned. Lead soakers are another option but you will need to leave your render board higher up and won't look as crisp Link to comment Share on other sites More sharing options...
Cpd Posted February 23, 2019 Share Posted February 23, 2019 2 hours ago, dpmiller said: I'm just in the process of doing this, and used an aluminium soaker http://www.kytun.com/p/continuous-aluminium-soaker-24m-blue_black/c14bb just need to stop the battens a bit short for it. Thie link you show is what I would call a valley not a soaker....... but This would be an improvement on a home made lead valley and used with modern slates would, I think work well. If your In a woodland environment or an area prone to leaf build up I would make sure you have looked at all options as soakers on each slate would not be susceptible to getting g blocked. I used soakers around my chimney breast and dressed a piece if lead down over the top and it worked really well. Uses a lot more lead...... but modern aluminium soakers and cover plate could look crisp if done well. Link to comment Share on other sites More sharing options...
dpmiller Posted February 23, 2019 Share Posted February 23, 2019 no trees nearby for us and a good 30mm of an open gully, the way the tiles worked out. If that gets blocked I'll be very surprised! 1 Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 24, 2019 Share Posted February 24, 2019 Should there not be a 150mm upstanding to the roof before any render board to allow for rain bounce not sure on current regs but a lead upstand always had to be that high, just the same as distance from ground to damp course. Link to comment Share on other sites More sharing options...
Triassic Posted February 24, 2019 Author Share Posted February 24, 2019 (edited) Thanks for all the pointers. You learn something new everyday, apparently the feature I have is called a step wall 14 hours ago, Cpd said: I’m thinking I’ll use the aluminium stepped flashing, no hidden valley as we have loads of trees around. I just need to work out the detailing around the render board finish that is to be applied to the step wall, as it will project from the wall around 50mm. Edited February 24, 2019 by Triassic Link to comment Share on other sites More sharing options...
Ed Davies Posted February 24, 2019 Share Posted February 24, 2019 11 hours ago, Cpd said: Thie link you show is what I would call a valley not a soaker....... Ugger, just looked at that link to find out what a soaker is. So, what's a soaker, then? Link to comment Share on other sites More sharing options...
Cpd Posted February 24, 2019 Share Posted February 24, 2019 What I call soakers..... are single L shaped pieces of thin metal that slot under each slate and go up the wall, they then have a cover strip over them to prevent water ingress from above. This is my chimney where I used lead as I needed to mould it round the tradional slates as you can see the piece under the lead extends quite a way so even if you got a moss or leaf build up in the corner water would not be able to back up and cause any problems, Link to comment Share on other sites More sharing options...
PeterW Posted February 24, 2019 Share Posted February 24, 2019 I know these as soakers too - detail here https://leadsheet-autocad.co.uk/downloads/abutment-with-soakers-and-step-flashings-slates-2f/ Link to comment Share on other sites More sharing options...
makie Posted February 24, 2019 Share Posted February 24, 2019 16 hours ago, Cpd said: Thie link you show is what I would call a valley not a soaker....... but This would be an improvement on a home made lead valley and used with modern slates would, I think work well. If your In a woodland environment or an area prone to leaf build up I would make sure you have looked at all options as soakers on each slate would not be susceptible to getting g blocked. I used soakers around my chimney breast and dressed a piece if lead down over the top and it worked really well. Uses a lot more lead...... but modern aluminium soakers and cover plate could look crisp if done well. Just pointing out that this is a watergate not a valley. Link to comment Share on other sites More sharing options...
dpmiller Posted February 24, 2019 Share Posted February 24, 2019 7 hours ago, Russell griffiths said: Should there not be a 150mm upstanding to the roof before any render board to allow for rain bounce not sure on current regs but a lead upstand always had to be that high, just the same as distance from ground to damp course. Dunno, looks like 65mm here? https://leadsheet-autocad.co.uk/downloads/abutment-flashing-with-secret-gutter-5f/ Link to comment Share on other sites More sharing options...
makie Posted February 24, 2019 Share Posted February 24, 2019 1 minute ago, dpmiller said: Dunno, looks like 65mm here? https://leadsheet-autocad.co.uk/downloads/abutment-flashing-with-secret-gutter-5f/ 100mm is the standard for a cover flashing up-stand in my area and 125mm for it to be raggled into the wall Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 24, 2019 Share Posted February 24, 2019 I think bc turn a blind eye to the upstand height, but be aware of the render discolouration if you have it to close to your roof, as rain bounce will splash up on to it. Link to comment Share on other sites More sharing options...
Ed Davies Posted February 24, 2019 Share Posted February 24, 2019 7 hours ago, Cpd said: What I call soakers..... are single L shaped pieces of thin metal that slot under each slate and go up the wall, Thanks @Cpd, very useful description. I guess the key is that the metal is mailable enough to conform reasonably well to the bottom of the slate so provide enough of a seal that water does run under the slates much? Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 24, 2019 Share Posted February 24, 2019 2 minutes ago, Ed Davies said: Thanks @Cpd, very useful description. I guess the key is that the metal is mailable enough to conform reasonably well to the bottom of the slate so provide enough of a seal that water does run under the slates much? They don’t really work like that they don’t need to conform to the slate at all. What thay basically do is put a right angle on your slate. Imagine you where hand forming fake slates out of tin, you would bend a right angle in the ones that sat against the wall to prevent water running down the gap, well that’s what the soaker does it sits on top of the slate to make a right angle, the next slate sits on top so the soaker is not visible, you then place another soaker, they are laid in a bond type configuration just like your eaves slates, by having one below another you create a bond pattern and remove the straight gap that you would have hope that made sense. 1 Link to comment Share on other sites More sharing options...
Cpd Posted February 24, 2019 Share Posted February 24, 2019 23 minutes ago, Ed Davies said: Thanks @Cpd, very useful description. I guess the key is that the metal is mailable enough to conform reasonably well to the bottom of the slate so provide enough of a seal that water does run under the slates much? Russell’s description is right. However because I am using very traditional slates they can be up to 15mm or more thick and when you’ve got them all overlapping it can soon add up to a thick layer of stone.... I also live in a very windy location and if I did not have a malleable material there would be a big old gap below each soaker and therefore I use lead as I can form it up and around the slates and then run it under the slate to beyond the next slate joint or wherever I feel is appropriate. The Lower part of lead you see in my photo is the chimney breast skirt as shown in the photo below. I like using lead as it’s fun to work with, I have learnt to solder it with very good results, clean joints that have not failed in 6 years so far. On a modern build I really don’t think you would need it as there are great alternatives that and cleaner and will give a much more crisp finish. 1 Link to comment Share on other sites More sharing options...
Pete Posted February 25, 2019 Share Posted February 25, 2019 17 hours ago, Russell griffiths said: I think bc turn a blind eye to the upstand height, but be aware of the render discolouration if you have it to close to your roof, as rain bounce will splash up on to it. We have used a Parex render system and we have applied Paragard to seal the render, it is a silicone based liquid that is just a milky liquid that dries clear. You can see the rain just runs off it and does not soak the render and it has PVC render beads at the bottom so hopefully this should overcome the rain bounce. (we hope) Link to comment Share on other sites More sharing options...
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