maxdavie

Sorry! I designed it, but I'm not showing all the info in the detail, ie, its cropped and I've removed annotations. So your suspicion is totally understandable. For various reasons on this project I have to have a level threshold, hence the timber frame sitting below the ground level. The rectangle to the left of the red board is a french drain and runs the perimeter of the building.

Hello, Does anyone know what is typically used for the element highlighted in red in the detail below? Pretty much all the details I've found online just say 'protective board'. Whatever it is it will have to be able to accept paint as it will be visible beneath the timber cladding. The detail shows: - a plywood timber 'cassette' - non-combustible Muliti-pro exterior lining - a timber rainscreen (battens, counter battens and Larch board-on-board cladding) There is a breather membrane over the Muilti-pro board and a DPM but I'm not showing it for drawing legibility. I imagine what I'm looking for is some sort of waterproof render carrier board that I can adhere to the slab edge and the 'cassette'. Then I'd apply sand/cement render to the small section of exposed surface and paint it. But, if anyone with experience/knowledge can steer me toward a particular product or key words/phrases to aid my google search or even correct my faulty assumptions that would be very helpful! Thanks

Thanks for the additional advice and comments Iceverge

Hi Iceverge, Thanks so much for the advice and your keen eye - this is a massive help! Yes, in essence, my system is very similar to that one shown on Grand Designs. I've attached a screenshot preview of the system as it will look behind the membranes and rainscreen in case you're curious. Okay, I've had a re-think of this detail based on your advice. I'll use some rigid insulation with greater compressive strength like Compacfoam which I can bond to the slab and raise the threshold cill piece and shuffle it over to drip into the slot drain channel. The ply and insulation edges can then slide back behind the Compacfoam into the warm interior. I'm not sure how to totally eliminate the cold bridge of the threshold cill piece. I haven't seen any thermally broken threshold cill pieces on the market. Maybe I can just find a thinner one. Re airtightness between door and floor - I'm planning on using the Proctor Wraptite Airtightness Barrier over the walls and behind the rainscreen in conjunction with the DPM (which is also airtight, though not vapour permeable) to complete the airtight seal under the threshold cill piece. See images - I'll first fold the DPM (in dark blue) over the top of the Compacfoam (light blue) and fix down. Then, I'll bring the airtight membrane down to lap over the DPM by say 100mm and fold it back over the DPM at the threshold with tapes. Then, sit the threshold cill piece over. See final detail. Any further comments of course welcome and greatly appreciated. Thanks again for the advice - I imagine I might be returning to seek the sage advice from fellow builders/architects/self builders in the future!

Hello, I was wondering whether anyone could offer any thoughts or advice about the following threshold detail. I'm actually an architect myself and am working solo, so I don't get the benefit of second opinions. I've always worked on larger schemes at the earlier 'conceptual' stage of projects so my practical knowledge of construction details is a little rusty now. This spring, I'm piloting a digitally-enabled kit-of-parts construction system assembled from cnc-cut plywood or OSB that I've been in the process of developing over the last year. Its just a small garden room, so I'm not too concerned about U-values, but I am trying to achieve airtightness to test out how all the details work before I self build our family home next year. I'll then have it tested to see how airtight it is. So, on to the detail - see image attached. Here's the floor build up from top to bottom: 50mm brick pavers, 10mm mortar bed, 18mm T&G Wisa Ply floated floor, 60mm Rigid insulation, RC slab. I'm thinking I can just secure the concrete threshold piece into a bed of mortar over the floated ply substrate - just like the brick. The DPM coming up the slab edge can fold over and tuck under the threshold piece protecting the exposed edges of ply and insulation. An additional waterproof board will go over the DMP too. The only reason I'm questioning it is because I haven't found many examples of how it is done online and so am relying purely on my knowledge/research and common sense. Anyway, any thoughts greatly appreciated. Thanks