Browse Forums General Discussion 1 Oct 29, 2024 7:51 am Hi fellow homeoners, I have just received my soil test result today and the geotech has classify my site as 'P' due to fill and abnormal moisture conditions - recently removed trees and trees adjacent. My soil is classified as H1. They are recommending a E waffle slab (E for engineered?) of slab fabric SL92 for my double storey home. Slab thickness is noted as 85mm. Piering is required and is been mark as 'Full', 3300mm depth. I have not gone to my tender appointment but will be in the coming weeks. Just wondering is that a terrible piece of land that I have bought? Am I gonna expect significant site cost? Any advice will be appreciated! Re: Soil result 2Oct 29, 2024 4:58 pm First E for extreme reactive. H1 is first degree high reactive. 3.3m of fill is a lot for conventional concrete piers to go through without reinforcements and even if you get to a natural layer it might not have the required bearing capacity for the concrete slab and two storey loads as the slab would need to be suspended. This is not a standard design of waffle slab. Most likely you would be looking at a conventional concrete suspended slab on screw piles. Expect heavy reinforcements for the slab in addition to cost of screw piles. This may not be cheap. Re: Soil result 3Oct 29, 2024 5:29 pm Eng. B A Hey thanks for reviewing it for me. I went through my report again and I think we only have 1m of fill. So they made 3 boreholes, 1 has no fill, the other two are 1m and 0.4m respectively. So maybe I have interpreted the terms wrong. I got the 3300mm figures from the Piering section below under 'Pier founding depth'. Please let me know if they are intending to put the pier down that deep. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Soil result 5Oct 29, 2024 6:39 pm I believe the problem is in borehole 2 which has fill down to 1m, although the fill looks like is compacted but you would need piers through it (P.S piers under the whole slab to avoid differential movement). Unless this hole is non representative of the building location or you are doing some cut in that area to take the fill away or find a certificate for the fill from the developer. Andrea You are welcome. I know we over engineer our slabs, as we have to give a 6 year structural warranty so we think its prudent to spend a little extra up front, for… 13 14882 With that sort of soil type if you ask for a design to include piers then I would also include void formers. That way you should reduce the chances of settlement and heave. 7 25617 PM me your email. I have a build excavation calculator you can use based on your plans to double check what your builder is telling you. Cheers Simeon 1 25348 |