crispy_wafer Posted June 18, 2021 Share Posted June 18, 2021 Anybody have recommendations for choice of membrane to use when employing the Tony tray method of maintaining airtightness around first floor joists. Many thanks. Link to comment Share on other sites More sharing options...
ProDave Posted June 18, 2021 Share Posted June 18, 2021 The best (and probably most expensive) is Intello. Second best and cheaper but not as tough is Proteck Barriar 1 Link to comment Share on other sites More sharing options...
CC45 Posted June 18, 2021 Share Posted June 18, 2021 I would make sure it does have some degree of breathability if you are using timber. Dont want anything rotting. Link to comment Share on other sites More sharing options...
Thorfun Posted June 18, 2021 Share Posted June 18, 2021 Don’t most manufacturers do their own version? e.g DuPont/Tyvek, Proctor, SIGA, ProClima, Protect, Gerband etc. with so many options it’s hard to know where to start but (as well as the recommendations above) you could check the Passiv House Institute? https://database.passivehouse.com/en/components/list/airtightness_system 1 Link to comment Share on other sites More sharing options...
Thorfun Posted June 18, 2021 Share Posted June 18, 2021 2 hours ago, CC45 said: I would make sure it does have some degree of breathability if you are using timber. Dont want anything rotting. So that would be one of the ‘smart’ membranes? Like the Intello Plus? Link to comment Share on other sites More sharing options...
crispy_wafer Posted June 19, 2021 Author Share Posted June 19, 2021 Thanks for the suggestions above, ought to mention it's a brick and block construction, airtightness isn't going to be up there with the best, but I'm striving to do the best I can. We did look at Manthorpe joist seals, but my pozi's are quite beefy at 122 by 300@400, told the manufacturer I didn't want any bounce, so these are probably overkill... The joist seals are 120. They will do special's if you ask, and was quoted about 680 for 48 from the BM, but my builder has everyone lined up on a conveyer and the joists are being installed next week, so not much time to act. My fault really for not communicating effectively and expecting stuff to be available off the shelf so to speak. Link to comment Share on other sites More sharing options...
jfb Posted June 19, 2021 Share Posted June 19, 2021 11 hours ago, crispy_wafer said: Thanks for the suggestions above, ought to mention it's a brick and block construction, airtightness isn't going to be up there with the best, but I'm striving to do the best I can Are you planning on a parge coat? No reason why block construction can’t be airtight - just needs attention to detail where different materials meet (as you are considering with the Tony tray) and some sort of render/parge coat on the blocks. Standard builder dot and dab won’t be airtight unless real care is taken by the builders (which is unlikely). 1 Link to comment Share on other sites More sharing options...
tonyshouse Posted June 19, 2021 Share Posted June 19, 2021 I used a breather membrane and hermetically sealed it to the blockwork by stapling an expanded metal lath over the edge and wet plastering over it 1 Link to comment Share on other sites More sharing options...
crispy_wafer Posted June 20, 2021 Author Share Posted June 20, 2021 21 hours ago, jfb said: Are you planning on a parge coat? No reason why block construction can’t be airtight - just needs attention to detail where different materials meet (as you are considering with the Tony tray) and some sort of render/parge coat on the blocks. Standard builder dot and dab won’t be airtight unless real care is taken by the builders (which is unlikely). Yes and no to the parge coat. Not fully decided... I need to look in more detail, if it something that I can DIY or am I gonna create a big mess then require a pro to come and sort me out. I'm confident enough to give stuff a go it's just biting the bullet and going for it. I've seen products like blowerproof and passive purple, but does this stuff actually work and provide longevity or will it just dry up and end up cracking and splitting a mastic would in a few years, i'd like to think it does work, but there be sharks out there, selling stuff to the uninitiated. Spoke to the builder about the tony tray idea, he liked the idea, however, I'm not going to end up in a world of hurt later with rotten joists by doing this am I? I guess that's where the breather membrane comes into it's own? But if something can breathe how can it keep draughts out? I guess all this has been done to death in the past - I'm a newbie and love to ask how and why... Link to comment Share on other sites More sharing options...
tonyshouse Posted June 20, 2021 Share Posted June 20, 2021 It is weird but breathable in this context means vapour open, ie let’s water molecules in and out but NOT wind! so long as joist ends are inside your insulation barrier they won’t gather condensation or get damp and rot, but beware of plumbing leaks Link to comment Share on other sites More sharing options...
jfb Posted June 21, 2021 Share Posted June 21, 2021 15 hours ago, crispy_wafer said: Yes and no to the parge coat. Not fully decided... I need to look in more detail, if it something that I can DIY I’m not an expert on parging but I believe it is pretty diy friendly. I think you can make up a wet slurry and then broom it on to the walls. Someone with more experience might be able to chip in. Link to comment Share on other sites More sharing options...
markc Posted June 21, 2021 Share Posted June 21, 2021 Parge coat is a great way to have a go or start to learn plastering, can be brushed or roller but quicker and more fun to use a float Link to comment Share on other sites More sharing options...
CC45 Posted June 21, 2021 Share Posted June 21, 2021 (edited) On 18/06/2021 at 23:25, Thorfun said: So that would be one of the ‘smart’ membranes? Like the Intello Plus? I just rung one of the various companies and asked - I wanted air tight but was told that it was a bad idea - just needed to be vapor permeable but air tight. This was 6 years ago now & I've forgotten which one I used. Give them a bell. Edited June 21, 2021 by CC45 correction Link to comment Share on other sites More sharing options...
Thorfun Posted June 21, 2021 Share Posted June 21, 2021 1 hour ago, CC45 said: I just rung one of the various companies and asked - I wanted air tight but was told that it was a bad idea - just needed to be vapor permeable but air tight. This was 6 years ago now & I've forgotten which one I used. Give them a bell. that's interesting as I thought the inner layer was a vapour control layer to stop vapour leaving the building? I know the smart ones let vapour in during the summer but wasn't sure that was entirely necessary in our climate. Link to comment Share on other sites More sharing options...
WWilts Posted November 17, 2021 Share Posted November 17, 2021 Any harm using just plain polythene around the joist ends and at the perimeter of the first floor void? The timber joists will breathe into the internal air space (room air). Looking for budget options. Link to comment Share on other sites More sharing options...
A_L Posted November 17, 2021 Share Posted November 17, 2021 5 minutes ago, WWilts said: Any harm using just plain polythene around the joist ends and at the perimeter of the first floor void? Assuming insulation outside the polythene then no. For longevity use heaviest gauge polythene you can get (DPM). 1 Link to comment Share on other sites More sharing options...
WWilts Posted December 2, 2021 Share Posted December 2, 2021 On 17/11/2021 at 11:17, WWilts said: just plain polythene around the joist ends and at the perimeter of the first floor void? The timber joists will breathe into the internal air space (room air). Looking for budget options. Budget option that works: Tyvek Housewrap. Airtight, vapour permeable. Link to comment Share on other sites More sharing options...
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