Browse Forums Building Standards; Getting It Right! 1 Jan 07, 2019 6:34 pm Hi just started building, however I’ve checked the engineering and states the slab is built on rolled fill (not controlled) 300mm and the edge beams are on this too. Can you confirm if that’s okay? waffle slab, as there was a cut and fill on my Slight sloped sight. Been approved by building surveyor but friend advised it can’t be on rolled fill? Thanks Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Edge beam on rolled fill? 3Jan 08, 2019 1:09 am Class P due to abnormal moisture And says it’s also class M due to 40mm not sure which one? Thanks Re: Edge beam on rolled fill? 4Jan 08, 2019 1:41 am Well, considering that footing are on ground and you have a lot of moisture and reactive clay, waffle pod itself can easily be a problem as when your soil gets wet, the clay will swell and move you slab up, when soil dries out, it will move slab and footings down. If this movement happens unevenly, slab can heave or crack. This might happen even if your pod sits on naturally compacted soil. But if you put un-compacted soil under your slab and edge beams, the amplitude of those movements might be times higher and you might end up with situation when the soil just moves out of the footings as in Lobby69 case in the neighbouring topic. Waffle pod on non-compacted fill without piers (which are connected to your slab) might be a serious risk (piers could be holding/limiting the movement via friction), but even with piers you still deal with point loading and soil movement under the slab. Even with piers, maintenance of very good drainage will be crucially required during the build and then after your house is built, you would have to watch very carefully that the water never stays near your slab edges (and this is sometimes not very easy to achieve). In your case, I would always prefer rafted slab on piers or, if you can afford it, a rafted slab on 600-700 mm well-compacted quality fill (e.g. crushed cement, sandstone, road base). Just my 2 cents based on common logic. Some structural engineers on this forum might provide a more weighted opinion. Re: Edge beam on rolled fill? 5Jan 08, 2019 10:24 pm alexp79 Well, considering that footing are on ground and you have a lot of moisture and reactive clay, waffle pod itself can easily be a problem as when your soil gets wet, the clay will swell and move you slab up, when soil dries out, it will move slab and footings down. If this movement happens unevenly, slab can heave or crack. This might happen even if your pod sits on naturally compacted soil. But if you put un-compacted soil under your slab and edge beams, the amplitude of those movements might be times higher and you might end up with situation when the soil just moves out of the footings as in Lobby69 case in the neighbouring topic. Waffle pod on non-compacted fill without piers (which are connected to your slab) might be a serious risk (piers could be holding/limiting the movement via friction), but even with piers you still deal with point loading and soil movement under the slab. Even with piers, maintenance of very good drainage will be crucially required during the build and then after your house is built, you would have to watch very carefully that the water never stays near your slab edges (and this is sometimes not very easy to achieve). In your case, I would always prefer rafted slab on piers or, if you can afford it, a rafted slab on 600-700 mm well-compacted quality fill (e.g. crushed cement, sandstone, road base). Just my 2 cents based on common logic. Some structural engineers on this forum might provide a more weighted opinion. Just my 5c worth. Re: Edge beam on rolled fill? 6Jan 08, 2019 11:10 pm Thanks, yeah waffle seems to be the standard, just that’s it’s rolled fill is the concern I have, and not controlled. Someone said there was a building code that doesn’t allow to be on rolled filled, but don’t have the code books. With all these issues of slabs and heave i don’t want to be the next. Re: Edge beam on rolled fill? 7Jan 09, 2019 5:57 am Newbuild19 Thanks, yeah waffle seems to be the standard, just that’s it’s rolled fill is the concern I have, and not controlled. Someone said there was a building code that doesn’t allow to be on rolled filled, but don’t have the code books. With all these issues of slabs and heave i don’t want to be the next. Re: Edge beam on rolled fill? 8Jan 09, 2019 6:32 am Newbuild19 Hi just started building, however I’ve checked the engineering and states the slab is built on rolled fill (not controlled) 300mm and the edge beams are on this too. Can you confirm if that’s okay? waffle slab, as there was a cut and fill on my Slight sloped sight. Been approved by building surveyor but friend advised it can’t be on rolled fill? Thanks Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Yes this is in AS2870-2011 6.4.2 to be compacted with repeated rolling of an excavator or similar and in 150mm layers if not sand Hello everyone, After some suggestions and ideas about how to put a concrete path around the drop edge beam area on our new build. We are required to have a concrete path… 0 12871 The distance between my DEBs varies from 4.1m at the narrowest to 8.1m at the widest. 5 27305 |