Browse Forums Building A New House 1 Sep 09, 2014 9:26 am Hi Guys, I was wondering if anyone can give me an idea how much extra it can cost for upgrading the slab from class H1 to P. As the soil test report indicated that the land was initially classified as P class however based on the asumption that as per the local city council requirement, they estate filled up under the supervision of the council authority and filled up to the optimal level and based on that assumption they redefined it as H1 class. Now my worry is if the builder comes back and say the expected compaction is not enough for H2 class and goes for P class, how much extra I may have out count out of my pocket? My land is 330SqM and the house footprint would be around 124SqM. As I'm going to sign the contract shortly, I'd need to calculate my budget ahead of it. I'd really appreciate if someone can shed some lights on this. Thanks and best regards, Rubab Re: How much it costs for changing the slab class from H1 to 2Sep 09, 2014 3:00 pm Its a open ended question once it is classed as a problem site a engineer will design your foundation.The engineer will decide if deep piers are necessary or rigid slab or screw piles etc. So you won't know until the engineer has a look at the soil test and your proposed building. Some things engineers will consider are Type.quality,depth and compaction of fill. Proposed building. type of construction materials footing type single storey or double etc My advice is don't trust what people are saying they are going to do instead try and get a fixed quote or your only soil test when it is possible Re: How much it costs for changing the slab class from H1 to 3Sep 10, 2014 11:54 am insider Its a open ended question once it is classed as a problem site a engineer will design your foundation.The engineer will decide if deep piers are necessary or rigid slab or screw piles etc. So you won't know until the engineer has a look at the soil test and your proposed building. Some things engineers will consider are Type.quality,depth and compaction of fill. Proposed building. type of construction materials footing type single storey or double etc My advice is don't trust what people are saying they are going to do instead try and get a fixed quote or your only soil test when it is possible Thank you so much Insider for your response. Actually I'm building a 2 story on this land and the soil test has been already done and the engineers mentioned that it initially got a P classification due to the amount of fill but based on the assumption that the local city council would have monitored the filling and certified with an optimum(allowable) level of fill, they redefined it as H2 class. Regarding the peiring, we have all the peiring covered by the builder. It's about the Slab and if there is any rock found those cost remains variable. Could you give me an idea how much it costs extra to change the H2 Slab only to a P class? Other than the piering is there any other cost involved in that case? A rough idea would be enough. Your response is much appreciated. Thanks and best regards Rubab Re: How much it costs for changing the slab class from H1 to 4Sep 10, 2014 11:47 pm Rubab Still not a 100% on what you mean. You are building a 2 storey house on a slab.The soil test has said it is filled so it is a "p" site and will need a engineer designed slab with piers.Your engineer then said we assume it is well compacted fill and has re classified the site as a"h2" slab.So if the engineer has reclassified the site as "h2" then you should no longer need piers ?. It does cost extra if your slab is on piers.Apart from the cost of piers the engineers have to strengthen the slab to cope with concentrated loads on the slab usually by increasing size and/or amount of steel reinforcement.They can also change the size and spacing of the beams. What this means is that cost will vary according to what changes the engineer will do to your slab so unfortunately the engineer is the only one able to answer your question about extra costs. The actual cost of the piers probably will be your biggest extra cost depending on the depth of your piers. Just on another thing I hope your engineer hasn't assumed the fill is good but has a compaction certificate and done their own test e.g. D.C.P test. Re: How much it costs for changing the slab class from H1 to 5Oct 01, 2014 12:07 pm The cost difference between the two types can vary significantly depending on what the engineering has stated. I would suggest looking closely at the engineering and soil test to see what has been detailed. 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 13063 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 9842 I don’t think so as the floor area over 300 square meters then it is class 3…. 12 17926 |