BotusBuild Posted February 14, 2022 Share Posted February 14, 2022 As you may have seen from my blogs, we are progressing well and getting ready for second floor of Nudura ICF construction, but we've hit a snag. I am looking for a sanity check and/or suggestions for alternative approach. Normally, at this stage, the floor joists and sheet flooring would go in, then the ICF can be put in place with the bracing for this floor being in place on the newly installed wood sheet floor. This was our plan, until my original waterproofing scheme was rejected and we have a new one that demands a 50mm screed be poured onto which the internal stud walls that support the floor joists will rest. The screed pouring companies say they will not pour until the house is weathertight (roof, walls, windows), but I can't achieve that until my second floor walls are in place. Got the picture? I am in a chicken and egg situation. So the plan I have come up with is: construct the partition wall frames that are necessary to support the joists and floor that I need to support the bracing for the second floor Nudura build-up, packing those partition panels out to keep the floor level-ish while we work. (note the frames, joists and floor sheeting will be the actual final items) Once the Nudura walls are up and concrete poured, we can then get the roof on, any window openings can be temporarily sealed Remove floor that needs to be removed to allow... screed poured and other waterproofing items completed Floor re-installed permanently I know that installing, removing and re-installing sounds crazy, but the joists will be there anyway, and I have to make the partition frames anyway. Any other suggestions I should consider (apart from wringing the neck of the person who came up the original waterproofing plan)? Link to comment Share on other sites More sharing options...
BotusBuild Posted February 15, 2022 Author Share Posted February 15, 2022 Any comments? Link to comment Share on other sites More sharing options...
Omnibuswoman Posted February 15, 2022 Share Posted February 15, 2022 I don’t have any sage advice unfortunately but I wonder if there are any structural engineers that specialise in ICF that could give you the benefit of their experience? I’m happy to ask our SE if she knows anyone with relevant expertise if you’d like? m Link to comment Share on other sites More sharing options...
ToughButterCup Posted February 15, 2022 Share Posted February 15, 2022 Ask Nudura to put you in touch with their SE Link to comment Share on other sites More sharing options...
Conor Posted February 15, 2022 Share Posted February 15, 2022 Other than changing to precast concrete floor slabs, the only option I can see is build the required stud walls.dorectly off your floor slab, lay floor joists at 1st floor level and screw down 22mm OSB boards around the perimeter to allow the bracing to be fixed to. Pour the walls, get your roof on pronto, then you can remove the temporary floor sheets and put your final 1st floor boards down when water tight. It'll cost you a few hundred in OSB and extra guarding, but I don't see any other options. Link to comment Share on other sites More sharing options...
BotusBuild Posted February 15, 2022 Author Share Posted February 15, 2022 7 hours ago, ToughButterCup said: Ask Nudura to put you in touch with their SE Thicko question and maybe I have missed something - how is an SE going to provide advice on how to build it? The problem I have is not to do with how strong it needs to be (I have all that info already), it is with the change of waterproofing system and how that impacts on how to construct. Link to comment Share on other sites More sharing options...
BotusBuild Posted February 15, 2022 Author Share Posted February 15, 2022 5 hours ago, Conor said: Other than changing to precast concrete floor slabs, the only option I can see is build the required stud walls.dorectly off your floor slab, lay floor joists at 1st floor level and screw down 22mm OSB boards around the perimeter to allow the bracing to be fixed to. Pour the walls, get your roof on pronto, then you can remove the temporary floor sheets and put your final 1st floor boards down when water tight. It'll cost you a few hundred in OSB and extra guarding, but I don't see any other options. Sort of similar, but at some point I have to pour the 50mm screed and the stud walls need to sit on that (in the final configuration) Link to comment Share on other sites More sharing options...
BotusBuild Posted February 15, 2022 Author Share Posted February 15, 2022 @Conor - thanks for reminding me they are called stud walls (and not partition panels as in my original post - it was written after a bad day at work and my brain was skewered) Link to comment Share on other sites More sharing options...
BotusBuild Posted February 15, 2022 Author Share Posted February 15, 2022 7 hours ago, Omnibuswoman said: I’m happy to ask our SE Thanks, but as I said to Ian above, not sure how an SE will help Link to comment Share on other sites More sharing options...
Nickfromwales Posted February 15, 2022 Share Posted February 15, 2022 Why can your ground floor stud walls be built atop a course of engineering bricks? They can then stay, and the screed gets poured / laid around them. What am I missing re what the stud walls will sit on? Link to comment Share on other sites More sharing options...
Conor Posted February 16, 2022 Share Posted February 16, 2022 12 hours ago, BotusBuild said: Sort of similar, but at some point I have to pour the 50mm screed and the stud walls need to sit on that (in the final configuration) Why this way? Why not on the slab or a course of aerated blocks? That's the way I did it. Link to comment Share on other sites More sharing options...
BotusBuild Posted February 16, 2022 Author Share Posted February 16, 2022 (edited) 12 hours ago, Nickfromwales said: What am I missing re what the stud walls will sit on? You're missing a detail that I missed out in the OP ? Apologies. The new waterproofing scheme dictates: On top of the existing concrete foundation slab a layer of waterproof cementitious slurry, a screed layer in order to form a drainage channel around the exterior of the floors, then a drainage membrane on top of that, on top of which will sit the stud walls @Conor - see above to your question "Why this way?" Edited February 16, 2022 by BotusBuild 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted February 16, 2022 Share Posted February 16, 2022 14 hours ago, BotusBuild said: Thicko question ... No such thing.... It would have helped had I read your OP with more care. In effect, I was adding to @Omnibuswoman's response. Apologies 1 Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 16, 2022 Share Posted February 16, 2022 (edited) Why not put the first floor joists in, place a a row of acrow props under the floor as dummy support in the place of the stud walls. Then build up Nudura and fit roof. Remove acro props, don’t allow anybody upstairs, pour floor screed and replace one or two acro props to take any sag out of floor, then build stud walls removing props as you go. Edited February 16, 2022 by Russell griffiths 1 Link to comment Share on other sites More sharing options...
BotusBuild Posted February 21, 2022 Author Share Posted February 21, 2022 Russell - I'd end up with an unsupported floor span of nearly 12m following that method. I think the risk would be too high even for me to take ? Link to comment Share on other sites More sharing options...
markc Posted February 21, 2022 Share Posted February 21, 2022 16 minutes ago, BotusBuild said: Russell - I'd end up with an unsupported floor span of nearly 12m following that method. I think the risk would be too high even for me to take ? It wouldn’t be unsupported, this is a pretty common method used by thousands of builders while removing walls, adding lintels etc. We have done it on railway bridges (big acro props) while trains are still running. Link to comment Share on other sites More sharing options...
BotusBuild Posted February 21, 2022 Author Share Posted February 21, 2022 On 16/02/2022 at 10:04, Russell griffiths said: Remove acro props, don’t allow anybody upstairs, pour floor screed @markc, at this point, what is supporting the floor? The screed would end up with holes in it, or things stuck in it. Link to comment Share on other sites More sharing options...
markc Posted February 21, 2022 Share Posted February 21, 2022 2 minutes ago, BotusBuild said: @markc, at this point, what is supporting the floor? The screed would end up with holes in it, or things stuck in it. Ahh, just re read all the previous notes and I see where you are coming from, I would leave the acros in and screed around them, no problem taking them out after and filling up the bit of missing screed. Link to comment Share on other sites More sharing options...
Mr Punter Posted February 21, 2022 Share Posted February 21, 2022 Type C waterproofing can be a pain. Do the screed in 50mm concrete or sharp sand / cement and leave it exposed. If it can't stand getting wet it won't do well on the wet side of the waterproofing system, where they will flood test it upon commissioning. Are you actually building the structural studwork on top of the drainage membrane? Link to comment Share on other sites More sharing options...
BotusBuild Posted February 21, 2022 Author Share Posted February 21, 2022 1 minute ago, Mr Punter said: Are you actually building the structural studwork on top of the drainage membrane? Yes, as per design from waterproofing company. Link to comment Share on other sites More sharing options...
Mr Punter Posted February 21, 2022 Share Posted February 21, 2022 Is this the dimpled stuff to allow water to flow under? How do you fix the studwork to it? Link to comment Share on other sites More sharing options...
BotusBuild Posted February 21, 2022 Author Share Posted February 21, 2022 10 hours ago, Mr Punter said: How do you fix the studwork to it? No such thing as a bad question ? I think it will have to be something like CT1 Link to comment Share on other sites More sharing options...
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