Dunc Posted Monday at 12:26 Posted Monday at 12:26 Can anyone advise on how to tidy up the membranes at sole plate level on a timber frame? I will have a 10mm render applied to the block work under the sole plate. DPC & radon barrier flapping over this. Breather membrane covers the external board (Medite Vent board) of the timber frame. This external board overhangs the sole plate by it's own thickness (12.5mm). Architect suggested folding DPC up under the breather membrane then bringing the breather membrane behind the render to tie it down. Feels like a mechanism to allow water between the blockwork and render? Any risks with folding the DPC upwards? Frame will be timber clad with vertical counder battens then horizontal battens. Obviously the vertical battens will pin the breather membrane at the bottom of the external board, but not to the sole plate, unless I pack that out...wondering if that might be a good idea? any advice greatly appreciated
saveasteading Posted Monday at 12:41 Posted Monday at 12:41 Stanley knife or scissors and cut flush outside. Inside OK left alone to overlap with the internal dpm. 1
Mr Punter Posted Monday at 12:55 Posted Monday at 12:55 I would fold the dpc down or cut it flush with the sole plate. You can drop the battens down to cover the sole plate as long as the cladding is at least 225mm above ground level. 1
Dunc Posted Monday at 13:13 Author Posted Monday at 13:13 So you'd just leave the sole plate exposed, other than the cladding?
saveasteading Posted Monday at 13:25 Posted Monday at 13:25 11 minutes ago, Dunc said: sole plate exposed Good point. I'd assumed this showed the current condition. Cladding with dpm must cover the sole plate.
Dunc Posted Monday at 14:18 Author Posted Monday at 14:18 Yes, photo is current condition: dpm under sole plate. Flap of breather membremane above. So if I cut the dpm fush, the breather membremane can flap over the sole plate. Maybe taped to the render?
JamesP Posted Monday at 14:20 Posted Monday at 14:20 (edited) Enclosed a drawing of sole plate detail on my build, not a builder but I brought the 40mm pavatherm flush with the sole plate and lapped the dpc under. Then batten, counter batten and Cedar. I would not leave it exposed. Would bring the medite board level with block and sole plate. Others will have ideas. Edited Monday at 14:20 by JamesP
Dunc Posted Monday at 14:48 Author Posted Monday at 14:48 thanks @JamesP so you took the DMP up behind the external insulation? No option on dropping the medite vent board - that's how it came from the factory. I might be able to put a fillet over the sole plate, but that's a lot of mucking about if it's not going to do anything beneficial. Option A: bring the breather membrane down to render level & ahere it (and the dpm?) to the render. Cladding over the top. Unsure what adhesive might work. If adhesive fails sole plate could become exposed to splash. Option B: take the DMP up behind the breather membrane. Breather membrane cut off at render level. If breather membrane fails or there is condensation behind it, this could run behind the dpm and affect the sole plate. But with the DMP lapped upwards, no risk of splash of the sole plate. In both cases unless I put a fillet of something over the sole plate, the membranes will have a bit (38x12mm) of free space to flap in.
JamesP Posted Monday at 18:31 Posted Monday at 18:31 (edited) Have had a quick look and the dpm is mostly cut short next to bottom of sole plate. I would just try and protect soleplate from water splashes, also fitted rodent stainless steel mesh behind cladding. I wrapped the breather membrane underneath the 40mm pavatherm, green. I extended the Cedar 50mm below batten to protect the sole plate. Once board, 2 x batten and cladding fitted probably 75mm proud of render face. Dodgy drawing enclosed. I would not create a pocket where damp could remain in B. Edited Monday at 18:32 by JamesP 1
gavztheouch Posted 4 hours ago Posted 4 hours ago My architect detail has the membrane taped to my foundation which is an insulated raft. It is taped with a tape that can be rendered over so it covered with the concrete render that covers the raft insulation. I’m not sure of the idea of taping the membrane to the raft as any water that gets behind it will be stuck. 1
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