Adrian Walker Posted May 6 Share Posted May 6 Are you looking for self levelling concrete. CEMEX do Evolution which works well. Link to comment Share on other sites More sharing options...
saveasteading Posted May 6 Share Posted May 6 2 hours ago, Duncan62 said: Doesn't seem worth having two layers?! A very good point. I don't think you will find spacers for 10mm anyway. Ahhh, but there are the bars the other direction too, 6mm or 10mm twice. and do gap remains. So it is a very heavy, single layer in mid slab. Have a word with your designer and ask for an explanation and a solution. You want an agreement to omit one layer, not to increase the slab depth. I also find the 25mm top cover strange. that will got very close to the surface because it is all approximate and it is wobbly stuff. The numbering on the sketch all seems to be random. It looks like it has been wrongly copied from someone else's system. Maybe time to pause and check the design is sound and people know what they are doing. Isn't that a very thin strip of insulation retaining the slab? And a cold bridge from slab, through sole plate to outdoors? 1 Link to comment Share on other sites More sharing options...
Duncan62 Posted May 7 Author Share Posted May 7 7 hours ago, saveasteading said: Have a word with your designer and ask for an explanation and a solution. You want an agreement to omit one layer, not to increase the slab depth. I also find the 25mm top cover strange. that will got very close to the surface because it is all approximate and it is wobbly stuff. Isn't that a very thin strip of insulation retaining the slab? And a cold bridge from slab, through sole plate to outdoors? Yes I'll give my SE a call this morning, see what she says. One layer would be ideal from labour (mine) point of view, tho will leave me with lefty over mesh. The pic is only representative. Our upstand is 180mm thick. Link to comment Share on other sites More sharing options...
Duncan62 Posted May 7 Author Share Posted May 7 9 hours ago, Adrian Walker said: Are you looking for self levelling concrete. CEMEX do Evolution which works well. Have you used it? Got any hard won advice please? Link to comment Share on other sites More sharing options...
Chanmenie Posted May 7 Share Posted May 7 @Duncan62 here’s some blurb on the stuff I had http://www.easternconcrete.co.uk/wp-content/uploads/2018/07/GDA-443_EcFlow-Nov2017.pdf Link to comment Share on other sites More sharing options...
George Posted May 7 Share Posted May 7 (edited) 12 hours ago, Duncan62 said: Mesh spacing for our garage 150mm slab. Bottom cover 75mm Top cover 25mm 2x layers of mesh is 20mm + 20mm = 40mm. So 75+25+40= 140mm = 10mm space between the layers... Doesn't seem worth having two layers?! That's bonkers and in a concrete with 20mm aggregate, not compliant to the standards (smallest gap needs to be at least agg size + 5mm) On the topic of fibre reinforced rafts - I don't see them as a complete replacement to steel mesh. If there's any potential spanning (which is usually what rafts are designed to) I do not see how they can be made to work. That's not to say they won't work/will fail (esp for domestic rafts) but I think they are not 'working' like a raft and insteads are like isolated foundations and ground bearing slabs bound together with fiber reinforced concrete. I wouldn't want it on my PI. On the topic of self-compacting concrete - this is not a use case I would normally expect to see it. A poker and polishing is more normal. However that's not to say it doesn't work and if they are passing on the savings and can guarantee the work then crack on. Edited May 7 by George Link to comment Share on other sites More sharing options...
Duncan62 Posted May 7 Author Share Posted May 7 4 hours ago, Chanmenie said: @Duncan62 here’s some blurb on the stuff I had http://www.easternconcrete.co.uk/wp-content/uploads/2018/07/GDA-443_EcFlow-Nov2017.pdf Great, thank you. Eastern Concrete are only down the road from me too. Link to comment Share on other sites More sharing options...
Duncan62 Posted May 7 Author Share Posted May 7 3 hours ago, George said: That's bonkers and in a concrete with 20mm aggregate, not compliant to the standards (smallest gap needs to be at least agg size + 5mm) Yes it is, phoned SE today and asked the question: low and behold - 1 layer A393 will be sufficient. Wish I was an SE who over spec'd - so I could reduce reinforcement by 50% and not worry. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted May 7 Share Posted May 7 If you have an insulated slab/raft with UFH pipework in it, what stops the over enthusiastic worker damaging either with their vibrating poker? Link to comment Share on other sites More sharing options...
saveasteading Posted May 7 Share Posted May 7 5 hours ago, Duncan62 said: 1 layer A393 will be sufficient. Hoorah. I have said this to lots of people but it's great that it worked for you. The merchant should take back the surplus as long as you pay transport and allow them the loss of profit. so ask very nicely. 8 hours ago, George said: If there's any potential spanning But this is sitting on eps with a bearing strength of...not much, and isn't supporting the structure. OOPS I've looked back at the sketch provided and it shows the outer walls sitting on a bit of slab and a bit of eps, all on top of EPS. THIS IS A FAULTY DESIGN. STOP. Likewise, what are inner walls sitting on? @Duncan62 Have you prepared that sketch provided, using details from other systems? It is wrong in so many ways, but the worst is that the stud wall sitting like it does will not be supported. Link to comment Share on other sites More sharing options...
Duncan62 Posted May 7 Author Share Posted May 7 57 minutes ago, saveasteading said: Hoorah. I have said this to lots of people but it's great that it worked for you. The merchant should take back the surplus as long as you pay transport and allow them the loss of profit. so ask very nicely. But this is sitting on eps with a bearing strength of...not much, and isn't supporting the structure. OOPS I've looked back at the sketch provided and it shows the outer walls sitting on a bit of slab and a bit of eps, all on top of EPS. THIS IS A FAULTY DESIGN. STOP. Likewise, what are inner walls sitting on? @Duncan62 Have you prepared that sketch provided, using details from other systems? It is wrong in so many ways, but the worst is that the stud wall sitting like it does will not be supported. The sketch was a generic from the brochure. I'm very happy with the design. Wooden 300 IBeam 2/3 on slab, 1/3 overhang to give continuity of insulation and reduce thermal bridge. Permanent compressive strength, creep (50 years, compression < 2%) 130 kPa (EN 1606). Also have a stability check of the 1/3 overlap of the wall over the XPS from the slab by the SE. House raft has two layers of mesh, garage now reduced to one. Link to comment Share on other sites More sharing options...
Duncan62 Posted May 7 Author Share Posted May 7 6 hours ago, SteamyTea said: If you have an insulated slab/raft with UFH pipework in it, what stops the over enthusiastic worker damaging either with their vibrating poker? Another reason to use SCC! Link to comment Share on other sites More sharing options...
saveasteading Posted May 7 Share Posted May 7 4 hours ago, Duncan62 said: I'm very happy with the design. OK> I'm not but it isn't my house or problem, and so I will leave this conversation. Link to comment Share on other sites More sharing options...
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