kandgmitchell Posted February 26 Share Posted February 26 Just to add to the wealth of knowledge on here. We have just completed our insulated raft using xps with concrete 250mm thick at 100m2. Installed the foul drains and surface water out to a soakaway. All in, including labour it's come to £26K and a bit. Hope this might help with others budgeting. 2 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted February 26 Share Posted February 26 Any pictures? Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 26 Author Share Posted February 26 Yes, I'll post a few. Link to comment Share on other sites More sharing options...
mike2016 Posted February 26 Share Posted February 26 How did you handle door openings, any special shuttering / detailing required? Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 26 Author Share Posted February 26 This is to take a DanWood timber frame. The frame sits on the edge of the slab with the exterior insulation overhanging. More insulation goes ontop of the slab and an insulated former is used at door openings (from what I can see from the details provided). No special shuttering although we backed the vertical insulation with scaffold boards just in case. Be honest I doubt if they were needed though. It was a Green Raft that uses a vertical plastic joining strip between the horizontal and vertical insulation panels. Link to comment Share on other sites More sharing options...
Duncan62 Posted February 26 Share Posted February 26 Did Mark install or did you DIY? Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 27 Author Share Posted February 27 Mark? It was a "self" install with groundworkers doing the heavy stuff and me making sure the details were done properly. Took a while simply beacuse of the number of wet days when the site was just too muddy to work in. Link to comment Share on other sites More sharing options...
Dunc Posted February 28 Share Posted February 28 @kandgmitchell May I ask: how big is the raft (square meterage) and roughly what shape (simple rectangle vs something fancy)? I've just had my quote from MBC for ours and nearly fell off my chair... thanks Link to comment Share on other sites More sharing options...
scottishjohn Posted February 28 Share Posted February 28 (edited) On 26/02/2024 at 16:15, kandgmitchell said: Just to add to the wealth of knowledge on here. We have just completed our insulated raft using xps with concrete 250mm thick at 100m2. Installed the foul drains and surface water out to a soakaway. All in, including labour it's come to £26K and a bit. Hope this might help with others budgeting. Idid look at that but as we have 700mm original granite walls it was not possible webasically have a modern wood framed house inside granite walls so we went for concrete sub floor --100mm of pir and up the walls then ufh and going screed ontop of that Edited February 28 by scottishjohn Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 28 Author Share Posted February 28 44 minutes ago, Dunc said: May I ask: how big is the raft (square meterage) and roughly what shape (simple rectangle vs something fancy)? Nigh on 100m2 simple rectangle but with two pairs of 200mm x 850mm "outshoots" which support an open gable feature on the rear and front elevations. 1 Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 28 Author Share Posted February 28 We had MBC price the job last year. Their quote (April 2023) for an insulated raft for the same building design was £34K. Just a note, DanWood add their own insulation ontop of the slab so we used 150mm xps under. 1 Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 29 Author Share Posted February 29 As asked for here are some photo's. 8043 is the stone base done. 8046 the sand blinding, 8047 the sub raft insulation under way. Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 29 Author Share Posted February 29 Final two photo's 8053 is the steel, sorry it was getting dark when I rembered to take this. Layer of A393 mesh in bottom and top with a further layer of A393 min 1.0 m wide around the upper perimeter (we just used the 1.4m offcuts from the main mesh). A couple of embedded beams using 16mm bars where the main load bearing walls are. 8059 is the finished raft with a muddy surface due to the state of the ground whilst the rain water drainage was being done. I'll power wash it off before the frame arrives. 2 1 Link to comment Share on other sites More sharing options...
jack Posted February 29 Share Posted February 29 Thanks for the photos. Is your stone base MOT1 or similar? I've more commonly seen large no-fines stone specced - something like railway ballast. Link to comment Share on other sites More sharing options...
tuftythesquirrel Posted February 29 Share Posted February 29 On 26/02/2024 at 16:15, kandgmitchell said: Just to add to the wealth of knowledge on here. We have just completed our insulated raft using xps with concrete 250mm thick at 100m2. Installed the foul drains and surface water out to a soakaway. All in, including labour it's come to £26K and a bit. Hope this might help with others budgeting. Could you tell me how thick was the XPS as it will affect the budget if I go thicker. Thanks. Link to comment Share on other sites More sharing options...
kandgmitchell Posted February 29 Author Share Posted February 29 The stone was MOT1 type stuff which I think is max 30mm downwards. It packed tight with a 2T vibrating roller. I used 150mm xps for the insulation because the Dan Wood spec uses 90mm of insulation across the top of the raft. I could have added more but it was diminishing returns really. 1 Link to comment Share on other sites More sharing options...
kandgmitchell Posted March 28 Author Share Posted March 28 Just to add to this with a bit of experience of what I would do differently "next time". I had installed 50mm twin wall duct for the electric supply. After completing the raft that duct was extended by the groundworkers to the electric kiosk with the meter some 20 odd metres away. Only later did I consider the cable needs - 3 phase 25mm. Upon picking it up from the suppliers I could immediately sense a problem coming. A) it was heavy and B) it didn't bend well. This week I discovered drawing it through a 50mm duct was not practical - should have used 80mm at least. Also the bends in the duct made pulling the cable through a nightmare. Luckily, after a struggle we got it outside the raft (all of 3 metres) but had to dig down to it and cut it open to get past the first (of several) too tight bends. Finally have strained back trying to pull it the last 5 metres - can't even bend over at present! Resourceful wife asked two random men in a family of four passing by to help and they very kindly stepped in and pulled it the last bit while I sat on the floor in a lot of pain. So, 1) work out cable needs in advance. 2) use a bigger duct than you think you need 3) consider running the cable through the duct laid out in a straight line, then placing both duct and cable in place in one go so you know it will bend where you need it to! 4) just get someone else younger and fitter to do it! 1 1 Link to comment Share on other sites More sharing options...
joe90 Posted March 28 Share Posted March 28 14 minutes ago, kandgmitchell said: just get someone else younger and fitter to do it! 🤣 Link to comment Share on other sites More sharing options...
kandgmitchell Posted March 28 Author Share Posted March 28 True, but one doesn't realise the years have caught up until you're caught out! 1 Link to comment Share on other sites More sharing options...
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