Browse Forums Building A New House 1 May 01, 2014 11:46 am Hi All Is anyone able to please (simply) explain the important differences between different site classes? I am looking at land which they advertised as a "Class A build" site which is a good thing and the likes of Class P is the worse in terms of geotech talk. However, generally all build contracts that I am aware of, allow/include costs for a repeg/site survey and soil tests (to name a few) to help inform their bulid/engineering requirements. All seems reasonable to me. Question is, what happens if the builder soil test results comes back with a site class different to that advertised by the seller/written in the contract?? Then you get into debate over which consultant investigation/report is correct etc... I have asked to see the geotech report/soil testing report from the developer upfront (prior to me making an offier) to see if we can eliminate this potential risk, or at least be comfortable, the chance of it happening is very slim. Interested to hear your thoughts/reponses. Thanks Re: Class of Build Sites 2May 01, 2014 1:04 pm Site classifications based on soil reactivity Class A Stable, non-reactive. Most sand and rock sites. Little or no ground movement likely as a result of moisture changes. Class S Slightly reactive clay sites. May experience slight ground movement as a result of moisture changes. Class M Moderately reactive clay or silt sites. May experience moderate ground movement as a result of moisture changes. Class H1 Highly reactive clay sites. May experience a high amount of ground movement as a result of moisture changes. Class H2 Highly reactive clay sites. May experience very high ground movement as a result of moisture changes. Class E Extremely reactive sites. May experience extreme amounts of ground movement as a result of moisture changes. Class P Problem sites. The ability of the soil to evenly bear a load is very poor. Sites may be classified as 'Class P' as a result of mine subsidence, landslip, collapse activity or coastal erosion (e.g. dunes), or soft soils with a lack of suitable bearing. Ground movement as a result of moisture changes may be very severe, and these sites are typically subject to abnormal moisture conditions resulting from things like trees, dams and poor site drainage. If you are building on a Class P site you will need to consult a structural engineer. Classes M-D, H1-D, H2-D and E-D The 'D' in these classifications refers to 'deep' movements in soil due to deep variances in moisture. These classifications are only found in dry areas (e.g. north of the Great Dividing range, in places like Stawell, Horsham, Mildura, Bendigo, Shepparton and Wangaratta). Stewie Edit. Brian Ashworth on his excellent site www.anewhouse.com.au has a blurb about developers vs builders site classification. http://www.anewhouse.com.au/2013/08/dif ... n-results/ Re: Class of Build Sites 3May 01, 2014 2:24 pm Any soil test on your block will give a fair estimation. Things like fill and clay content typically don't vary greatly over the space of a few m. Obviously rocks do (hit or miss). Without paying money, there's a couple of ways to get a general idea. If you are in a subdivision you can ask close neighbors how their soil tests fared. One thing I found particularly useful was old aerial photography of our subdivision. With websites like Google maps/earth, LPI SIX maps and Nearmap, you can get detailed images of not only how your land looked prior to bobcats, but also at various stages of development. These can help paint a picture as to whether your block was mostly cut or fill. Re: Class of Build Sites 4May 01, 2014 2:54 pm Also go into your local council - ours had a soil report that the developer had done for each block. You're not able to take a copy but at least you'll be able to see what a previous test said. In saying that though we had the soil test of the developer, and two further soil tests done with tenders. Results M, H1 and P. http://camdenbuild.blogspot.com.au/ by invite only please pm me Re: Class of Build Sites 5May 02, 2014 5:45 pm Thanks everyone for your suggestions and links. I will call the council and see what they hold from the subdivision process. Titles haven't been issues yet was roads/curbs/utilties and enteral site works are not quite finished. I'm told that other landowners (whose offers will be subject to title issue) haven't yet been given access To do any of their own soil tests etc yet. However, Apparently we can gain access once the developer has the deposited plan done which will be before titles are issued to help get the "build" ball rolling. Re: Class of Build Sites 6May 12, 2014 12:28 pm Hi, I just received my soil test results and its really confusing, they came up as "P: Due to presence of fill" then underneath " reactivity S classification" - then they went on to say that the presence of fill was app 300mm deep. Does that mean I should be concerned we have P soil....? Or not too worried because the footings will be in the S soil? Re: Class of Build Sites 7May 12, 2014 1:05 pm Brooke_n_Ron Hi, I just received my soil test results and its really confusing, they came up as "P: Due to presence of fill" then underneath " reactivity S classification" - then they went on to say that the presence of fill was app 300mm deep. Does that mean I should be concerned we have P soil....? Or not too worried because the footings will be in the S soil? I dont know if this will help or not... Our site is H1-P (Highly reactive soils, but classed as a P site due to 300mm of fill on top) The report stated the only reason it was a P site, was due to the fill. There was a compaction certificate provided and our total footings/site works came to $18,000 in the end. We originally budgeted around $23k, so we were happy Thread: viewtopic.php?f=31&t=66299 Slab: 16/6/14 Frame: 4/7/14 Roof: 22/7/14 Lock Up: 20/8/14 Fixing: 26/8/14 PCI: 9/10/14 Handover: 20/10/14 Re: Class of Build Sites 8May 12, 2014 5:38 pm Brooke_n_Ron Hi, I just received my soil test results and its really confusing, they came up as "P: Due to presence of fill" then underneath " reactivity S classification" - then they went on to say that the presence of fill was app 300mm deep. Does that mean I should be concerned we have P soil....? Or not too worried because the footings will be in the S soil? The way I'd read that is somewhat similar to yourself. The reactivity of the soil is S, and the only concern they have is the amount of fill that could be Problematic, i.e. P. The person who organises the slab has it engineered based upon the S soil taking in to account the depth of the fill. On our sloping block our soil test came back with P representitive of H1. The P came about because of the trees in the area of where we wanted to have the house built, and that it could have been problematic if the roots weren't removed, as in they'd rot away eventually creating a subsistane of the soil under the slab. Our site prep including the excavations, the shredding of the trees, and the gravel driveway cost us around $19,000 ... I guess it would've cost me a hell of a lot more if I wasn't a owner builder, and had it done by a cookie cutter building company. Owner Building at Jimboomba Woods in Logan City Qld. Blog : http://bandlnewhomebuild.blogspot.com H1 thread : viewtopic.php?f=38&t=68283 . Re: Class of Build Sites 9May 17, 2014 12:21 am Brooke_n_Ron Hi, I just received my soil test results and its really confusing, they came up as "P: Due to presence of fill" then underneath " reactivity S classification" - then they went on to say that the presence of fill was app 300mm deep. Does that mean I should be concerned we have P soil....? Or not too worried because the footings will be in the S soil? Hi Brooke-n-Ron was the fill sand or clay and well compacted, also was the natural soil under the fill natural sand ? If you use a raft slab you can deepen the beams through the fill Re: Class of Build Sites 10Jun 03, 2014 5:49 am When a sloping site is excavated the soil profile is altered. One can often get a soil test re-done and the site reclassified. The real issue is what is the house sitting on? Re: Class of Build Sites 11Jun 03, 2014 7:32 am bpratt Brooke_n_Ron Hi, I just received my soil test results and its really confusing, they came up as "P: Due to presence of fill" then underneath " reactivity S classification" - then they went on to say that the presence of fill was app 300mm deep. Does that mean I should be concerned we have P soil....? Or not too worried because the footings will be in the S soil? The way I'd read that is somewhat similar to yourself. The reactivity of the soil is S, and the only concern they have is the amount of fill that could be Problematic, i.e. P. The person who organises the slab has it engineered based upon the S soil taking in to account the depth of the fill. On our sloping block our soil test came back with P representitive of H1. The P came about because of the trees in the area of where we wanted to have the house built, and that it could have been problematic if the roots weren't removed, as in they'd rot away eventually creating a subsistane of the soil under the slab. Our site prep including the excavations, the shredding of the trees, and the gravel driveway cost us around $19,000 ... I guess it would've cost me a hell of a lot more if I wasn't a owner builder, and had it done by a cookie cutter building company. The concern with the tree removal is the rebound from the clay as it re-hydrates and causes the clay to swell generally the engineers are not to concerned with the roots rotting unless it is a mass of roots or organic layer because the slabs can span distances under your slab e.g. think about the plumbing trenches under you slab Hi, We are looking for a builder that can build a small home (smaller length) on a sloping site. We came across Mojo's Zephyr design 10.6 m wide and 11.5 m length. Does… 0 23037 I don’t think so as the floor area over 300 square meters then it is class 3…. 12 17964 The Soil classification has little to do with piers. The purpose of the classing of the soil is to identify the clay content and the "average expected range of movement… 2 9895 |