Browse Forums Building A New House 1 Nov 11, 2022 4:46 pm Don't know if there's any engineers on here who can tell me if this seems right The outer edge of the sewer pipe is 1754 from the closest pier. Sydney water counts the Zone of Influence as a 45 degree angle starting 900 out from this, so a depth of 1750 - (1754 - 900) = 896 is required according to my calcs. Instead of 896 the engineer has prescribed a depth of 2600? I am now being charged for 2600 depth to all piers. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Sewer Zone of Influence - massive depth required 2Nov 12, 2022 8:36 am You can check pipe data depths easily on Before you dig Australia What's the invert level for the sewer line? this should have been sorted at the preliminary 3 builder quoting stage As for all piles being at a depth of 2600mm what does your geotech report say? OT, Too late now to ask the builder to reduce costs, you've signed and given a deposit hence no requirement to be competitive, guessing if he's got cash flow problems and folds up, lol, they start up all over again Sydney couple ‘sickened’ that building company will not have to pay debt Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Sewer Zone of Influence - massive depth required 3Nov 12, 2022 1:30 pm Whilst I get that the builder is dodge as , out of all the plethora of ways they can get more money from a client, would they really coordinate with the structural engineering crowd to require a depth of piering of 2600 vs required depth of 900? I mean, to get more money from a client why would they not choose one of the options that doesn't require them to do any additional work? (piering deeper) Re: Sewer Zone of Influence - massive depth required 4Nov 13, 2022 12:34 pm Hi boris594, It’s unlikely that the structural engineers are working with the builder to extract the maximum profit. Designs must be approved, and most reputable engineers wouldn’t risk their stamp by approving a design which can’t be substantiated if required. Lots of non-cash crabbing reasons could exist for the required pier deepening so I think a little harsh to assume that the builders are taking advantage without knowing the full picture. It could be a Sydney Water condition-they may have specified that settlement of the piers in the zone of influence is to be minimal. This usually means founding piers in reasonable quality rock which may explain the 2.6m depth (it will be indicated on the Geotech report, or some pier test holes done by builder). Sometimes Sydney Water also require that there is no possibility that loads are transferred to the ground surrounding the pier length due to friction (which can develop with long, thin footings) so loads are transferred to decent rock to remove this possibility. The 2.7m depth could also be due to the ground conditions. Regardless of the minimum depth to allow for sewer ZOI, the ground still needs to be adequate to support the proposed pier loads. As one corner of the slab is supported by piers probably founded on something decent, all piers need to be founded on similar material to reduce differential settlement/cracking of the slab, which is best practice, hence estimated depth of 2.6m all piers (in reality it will likely be the depth at which the auger stops advancing). There may be another reason for the pier deepening but there is likely to a good reason for it-ask the Structural Engineers and maybe request Sydney Water correspondence - you’re paying extra for it so it’s reasonable to expect a full explanation. You may find that rather than suspecting the builder/engineer are in some way maximising profits at your expense, the additional depth is justified, best design/construction practices are being employed and you have a far more robust footing system supporting the entire structure. You might find out they are fleecing you but at least it will be based on information rather than just suspicions. At worst compare the extra pier cost with the total cost of what they are supporting. To be fair on the builders pricing, Sydney Water requirements are usually determined at CC stage so the builder may not have been able to foresee Sydney Water requirements and allow for it in the initial estimate. Hi, only for walking. It is a narrow 1.5m paved area next to house. 2 5492 The distance between my DEBs varies from 4.1m at the narrowest to 8.1m at the widest. 5 27393 Yes it had a house on it. But Melbourne water only wanted something the original size of the existing house. We managed to fit a 45sq house on. 10 33720 |