Mulberry View Posted October 13, 2023 Share Posted October 13, 2023 Our First Floor layout is pretty simple. Here's our latest Posi design. I specified a target of under 10mm deflection, which this design achieves. What is the best way to hang these joists in a Nudura build? My current mindset is in fixing Ledger Plates to the long walls in the required places before the pour, with pocketed concrete protrusions and J-bolt fixings. This would remove the need for resin fixing and also the need for cutting back the insulation. Any pitfalls to this method? Beyond this, am I best to top chord hang the joists or use normal hangers onto the Ledgers? Link to comment Share on other sites More sharing options...
Russell griffiths Posted October 13, 2023 Share Posted October 13, 2023 The big problem with fitting the ledger board before the pour is the braces for the icf, if the ledger board is in the way it’s a right pain to fix the bracing. If your heights and design allows it to be fitted first then that’s what I would do. After that go for top hanging the joists, no hangers needed so money to save, and the sit really flat, just get the design done around that because there will be extra blocking between the joists to prevent sideways twisting. You will also also need some very very straight timber for the ledger board. i would use a metro beam from the joist manufacturer for them, and tell them if there not straight you will not accept them. Link to comment Share on other sites More sharing options...
Mulberry View Posted October 13, 2023 Author Share Posted October 13, 2023 1 minute ago, Russell griffiths said: The big problem with fitting the ledger board before the pour is the braces for the icf, if the ledger board is in the way it’s a right pain to fix the bracing. If your heights and design allows it to be fitted first then that’s what I would do. After that go for top hanging the joists, no hangers needed so money to save, and the sit really flat, just get the design done around that because there will be extra blocking between the joists to prevent sideways twisting. You will also also need some very very straight timber for the ledger board. i would use a metro beam from the joist manufacturer for them, and tell them if there not straight you will not accept them. Thanks @Russell griffiths. Yes, I'm aware of the difficulty in propping. I plan to install the props on timber on the walls where ledgers are. I think I can use the props/timber arrangement to hold the ledgers in place (along with Timberscrews), I've had this in mind for a while and am yet to think of a pitfall. Good point in the straightness of the Timber, I need to research metro beams as I've not heard of them. I had hoped to not receive the Posi joists yet, so it's obtaining the beams if they are to come from the Posi people, but that's not insurmountable. Regarding the hanging, top chord was my preference it was only that someone raised a concern about strength with the joists hanging only from the top chord. Doing so would also help me to take the strength even further and into 147mm wide beams (8mm deflection) if I so wished). Why do some opt to hang Posi joists on hangers placed in the core as opposed to ledgers? Link to comment Share on other sites More sharing options...
Russell griffiths Posted October 13, 2023 Share Posted October 13, 2023 Spell checking bloody iPad. Its not a metro beam. It’s a kerto beam, basically laminated plywood cut into a solid timber profile so just like your 9x2 or 225x 48. Whatever size your after, your joist manufactures should do them. Link to comment Share on other sites More sharing options...
Mulberry View Posted October 13, 2023 Author Share Posted October 13, 2023 2 hours ago, Russell griffiths said: Spell checking bloody iPad. Its not a metro beam. It’s a kerto beam, basically laminated plywood cut into a solid timber profile so just like your 9x2 or 225x 48. Whatever size your after, your joist manufactures should do them. Haha!! I emailed Pasquill asking them if they could help with Metro beams!! PMSL. Explains why I hadn't heard of it and why Google had nothing meaningful to offer. Link to comment Share on other sites More sharing options...
joe90 Posted October 13, 2023 Share Posted October 13, 2023 Is it also not known as “glulam” Link to comment Share on other sites More sharing options...
ProDave Posted October 13, 2023 Share Posted October 13, 2023 6 minutes ago, joe90 said: Is it also not known as “glulam” No. Glulam is large bits of timber glued together in layers, think bits of 4 by 2 glued together in layers in both planes to make whatever size you want. Kerto is literally overgrown plywood. Think thin strips of wood glued together in layers to whatever size you want them. We used Kerto beams for our roof ridge beam. According to the SE Kerto will give the same strength in a smaller size than a Glulam. But if lift on sight, a Glulam can be sanded and varnished and look quite nice. 1 Link to comment Share on other sites More sharing options...
Mulberry View Posted October 13, 2023 Author Share Posted October 13, 2023 (edited) Just one thing, I'm guessing Kerto beams must be kept completely dry? Moreso than Timber? That might scupper my plan. @Russell griffiths Edited October 13, 2023 by Mulberry View Link to comment Share on other sites More sharing options...
joe90 Posted October 13, 2023 Share Posted October 13, 2023 56 minutes ago, ProDave said: 1 hour ago, joe90 said: glulam” No Every day is a school day 👍 Link to comment Share on other sites More sharing options...
Russell griffiths Posted October 15, 2023 Share Posted October 15, 2023 On 13/10/2023 at 19:20, Mulberry View said: Just one thing, I'm guessing Kerto beams must be kept completely dry? Moreso than Timber? That might scupper my plan. @Russell griffiths Check with your supplier, mine sat out in all weather until the roof went on, probably 6-8 weeks, I believe it’s all waterproof glue like a version of D4 glue on steroids. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted October 15, 2023 Share Posted October 15, 2023 The veneers are bonded with weather- and boil-resistant phenol formaldehyde 1 Link to comment Share on other sites More sharing options...
Mulberry View Posted October 16, 2023 Author Share Posted October 16, 2023 Thank you, I've asked my Posi supplier to quote on these. I'm thinking of putting a layer of DPM between the Nudura and the Ledger, leaving it long at the top so I can pull it down over the Ledgers to keep them dry. I might be worrying over nothing, but if I get them up pre-pour, it'll be months rather than weeks before the roof is on. As for the top chord hanging, why do more people not do this? It just seems really tidy and simple to me. Link to comment Share on other sites More sharing options...
saveasteading Posted October 16, 2023 Share Posted October 16, 2023 You've got me reliving these products, and looking them up , as I used kerto big time a couple of times to replace steel. Reason? 1.Workability, joiners instead of steel fabricators, 2. Making up a solution on site with complex angles.... wood is easier than steel. Notes. Kerto is a trade name. LVL (laminated veneer lumber) may bring up other manufacturers. It is really strong and also hard. It needs a very good circular saw/ nail gun etc. Another product is made of longitudinzl shards of timbe in resin, like osb, but in beam sizes. Super strong. I can't remember it's name, or find it online. 2 Link to comment Share on other sites More sharing options...
joe90 Posted October 16, 2023 Share Posted October 16, 2023 1 hour ago, saveasteading said: Making up a solution on site with complex angles.... wood is easier than steel. Which is why in a few jobs I preferred glulams to steels 👍 1 Link to comment Share on other sites More sharing options...
saveasteading Posted October 16, 2023 Share Posted October 16, 2023 The middle of a glulam or Kerto seems such a waste of wood. The central layers of laminates are hardly working at all. Link to comment Share on other sites More sharing options...
BotusBuild Posted October 16, 2023 Share Posted October 16, 2023 On 13/10/2023 at 09:51, Mulberry View said: What is the best way to hang these joists in a Nudura build? Use Nudura joist hangers where you can (see pics after YT link) - https://www.nudura.com/media/1913/nuduraicf_monotruss_hanger_system.pdf In the left hand picture you'll see some pieces of wood bolted into the concrete after as the Nudura joist hangers could not be inserted prior to the pour. . 1 Link to comment Share on other sites More sharing options...
ProDave Posted October 16, 2023 Share Posted October 16, 2023 10 hours ago, saveasteading said: You've got me reliving these products, and looking them up , as I used kerto big time a couple of times to replace steel. Reason? 1.Workability, joiners instead of steel fabricators, Exactly the same for us, joiners cut all the compound angles for the gable end ridge beams on site. They made softwood templates first to establish the correct compound angles to cut, before cutting the real beams, all supplied a bit over length. I had some offcuts of Kerto beams left outside in the rain for a very long time without delaminating. 1 Link to comment Share on other sites More sharing options...
FM2015 Posted October 17, 2023 Share Posted October 17, 2023 Simpson strong tie ICF ledger bracket. Install before pour, fits flush, can be spaced around alignment system. Only issue is if you're using the xr35 block which requires a bit of a fiddle solution using makeup panels and webs. Still less expensive than the nudura system for the xr35. 1 Link to comment Share on other sites More sharing options...
FM2015 Posted October 17, 2023 Share Posted October 17, 2023 On 16/10/2023 at 17:19, BotusBuild said: Use Nudura joist hangers where you can (see pics after YT link) - https://www.nudura.com/media/1913/nuduraicf_monotruss_hanger_system.pdf In the left hand picture you'll see some pieces of wood bolted into the concrete after as the Nudura joist hangers could not be inserted prior to the pour. . Why didn't you use the Nudura retrofit brackets? Link to comment Share on other sites More sharing options...
Mulberry View Posted October 18, 2023 Author Share Posted October 18, 2023 On 17/10/2023 at 17:17, FM2015 said: Simpson strong tie ICF ledger bracket. Install before pour, fits flush, can be spaced around alignment system. Only issue is if you're using the xr35 block which requires a bit of a fiddle solution using makeup panels and webs. Still less expensive than the nudura system for the xr35. These are flippin' expensive, aren't they? Link to comment Share on other sites More sharing options...
Mulberry View Posted October 18, 2023 Author Share Posted October 18, 2023 On 17/10/2023 at 18:44, FM2015 said: Why didn't you use the Nudura retrofit brackets? They just don't inspire me with confidence of a strong, bounce-free floor the same as hanging the joists directly onto a Ledger (Rimboard). Link to comment Share on other sites More sharing options...
saveasteading Posted October 18, 2023 Share Posted October 18, 2023 7 minutes ago, Mulberry View said: a strong, bounce-free floor the same as hanging the joists Lots of nails hold the end tight, reducing deflection. In any case, joists are sized to a deflection that is comfortable, long before breaking strength becomes an issue. Link to comment Share on other sites More sharing options...
FM2015 Posted October 18, 2023 Share Posted October 18, 2023 3 hours ago, Mulberry View said: These are flippin' expensive, aren't they? Entirely relative. You use around 60%less units but you have to factor in the cost of the wall plate and the conventional joist hangers and nails. We pretty much never use the Nudura system, especially for the xr35 block because it works out more expensive. Be that on time or materials. Best advantage of the Simpsons though is the bearing point around the perimeter. Can be achieved other ways but yet to use one I'd recommend. The other advice is book price and purchase price can be wildly different. Nearly 50% off when I ring the supplier. Link to comment Share on other sites More sharing options...
BotusBuild Posted October 19, 2023 Share Posted October 19, 2023 On 17/10/2023 at 18:44, FM2015 said: Why didn't you use the Nudura retrofit brackets? Wasn't aware they existed at the time 😞 1 Link to comment Share on other sites More sharing options...
ChrisJ Posted October 20, 2023 Share Posted October 20, 2023 On 18/10/2023 at 19:46, Mulberry View said: These are flippin' expensive, aren't they? As pointed out the time savings is huge, you can set the initial bracket typically at 1.2m o.c. So at £20 per kit it’s not bad, when the ledger board is in place you don’t have to add solid blocking around the perimeter which is a huge time savings Link to comment Share on other sites More sharing options...
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