Browse Forums Building A New House 1 Dec 09, 2014 4:46 pm Hi all, i am newbie - please be nice with me if i am making mistake , I need some helps to understand the difference regarding P class and H2 with extra support. I have purchased a land in Point cook area and the soil report test came out with a P Class site due to up to 800mm infill. A few information about my land: 1. in the soil report, it does not say any moisture problem. 2. I provided L1 Compaction Report from land developer and it states it is a controlled infill. 3. The builder asked an engineer to design our slab and it came out with P / H2. The builder is charging me with a P class slab. (extra $5K). I asked a question to my builder, why did they charge me with P class slab? It came back with the following response "P is the condition of the site which include things such as old trees, an existing house that was demolished, back filled Damn etc. basically if the soil report shows inconsistency between test holes, it will be a P condition which may require blinding trench to the rear for eg but basically a H2 slab with extras. H2 is the classification. This is the highest classification before E which stands for full engineered designed. H2 is when test holes are consistent throughout the site" My questions: 1. Does this make sense to you all? are they overcharging me ? (build H2 with P class price?) 2. How to distinct engineer slab from H2 with extra supports and P class slab? Many thanks for your helps. THanks on3 Re: P class slab and H2 slab with Extras 2Jan 04, 2015 8:24 pm What did the soil report find and recommend ? The engineer must look at what your soil report,compaction report and proposed building are before making a judgement in regards to the design of your slab. Australian standards recommend class "p" if the site fill exceeds 0.4m of clay and 0.8m of sand. Your site has more than 0.4m of clay fill. Point cook has significant number of heave slabs most of then with reactive fill like your block. You are trusting a compaction report that is general in nature and may not have a test location near your particular block. From my experience and knowledge of your area I would be happy with a class "p" but asking the engineer to base it on a "e" type reactivity. Re: P class slab and H2 slab with Extras 3Jan 17, 2015 2:24 pm If you want to look at a 'here's one I prepared earlier' scenario's I am in 3030 with identical situation. Save yourself $000's and see what not to do. 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 7898 I am not sure whether Perth has its own way of doing things in regards to this. Most of Perth has class A (sandy soil), except for some areas near rivers or hills. 2 8270 I don’t think so as the floor area over 300 square meters then it is class 3…. 12 15884 |