Browse Forums Building A New House 1 Oct 13, 2013 11:20 pm Apparently our land is 'S' class (WA) and we require a C4 type footing (according to the land agent who had their own survey and recification works done) how much is this likely to add on top of the normal site works, which I believe are usually around $10-12k? Re: Advice required with foundation slab :- C4 footing requi 2Oct 17, 2013 10:01 pm Hi Matt, I'm not 100% sure as I am getting conflicting information. Basically the land agents had some tests done and the soil was found to have a clay content. After that, they cleared out the land and backfilled with 2.5m worth of sand. One builder (Gemmill) said if this is accurate then they could use a normal slab (subject to their own engineering report), so I would say that they agree with you. This is why I cant understand the land agent saying that a C4 footing is necessary. Here is some of the info from the report:- Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ thanks for your help!!! Re: Advice required with foundation slab :- C4 footing requi 3Oct 21, 2013 9:37 pm I don't know what has made your site classified as C4 footing design, but I'd ring and ask the engineers who have prepared the report. At a guess a c4 footing design will probably add 8-15k to your site costs, depending in builder and house size. We have a C8 footing design and our slab costs alone are an additional 25-30k. We have a clay site and there are a bunch if other site costs which have all added up to an unbelievable amount....... Re: Advice required with foundation slab :- C4 footing requi 4Oct 21, 2013 10:50 pm cornellengineers Hi again el diablo. I'm sorry but I'm not familiar with the C4 footing detail. The details you have uploaded look like really old details - so maybe they are the details used in WA in lieu of the Australian standard AS2870. Hope it works out for you. Matt Cornell http://www.cornellengineers.com.au thats WA for you lol!!! Re: Advice required with foundation slab :- C4 footing requi 5Sep 23, 2014 6:54 am Looks like C4 footings is the engineers specific footing design type and may have nothing to do with the aus standards. The report says there is 2.5m of fill in the estate so probably should be class "p" and re classified as "s" if the fill is good enough.I get a little nervous when the developer does the earthworks, testing and engineering design and the developer then tells you how good everything is. I would be interested in Matt's take on this situation. Re: Advice required with foundation slab :- C4 footing requi 6Feb 20, 2016 3:07 pm Since moving to WA from QLD I've discovered that this is a common practice over here. The builders have essentially demanded 'A' class soils from the developers due to most of Perth having natural sand soil - this is what they are used to. As sprawl has pushed developers into the foothills of the scarp and further north and south of the sand plains, the developers bring in sand fill to bring the soil class up. Due to this, they carry out a preliminary classification and receive a preliminary footing detail from the engineer (Structerre 99% of the time, hence why the Structerre coding system is used {C1, C2, C3, etc for double brick, F-20 etc for framed}). Due to the double brick method, which is Perth's standard, the soil class and footing detail has a HUGE bearing on the overall cost to construct, hence why this information is provided upfront by developers. Versaloc is a mortarless besser block system that still needs a properly engineered footing. If you just do a 400x200 footing it will fail in time. At 17m long you need it… 1 18279 yep sounds good make the footing bigger to to allow for the pipe in the middle 3 7330 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 10256 |