Browse Forums Building A New House Re: Waffle pod Void height. 8Jul 12, 2015 8:12 am mgilla Simply request the engineer design the slab bases on the next classification to what the soil test comes back. It is too late for that. My contract only included spending extra on the slab engineered for my site (H2). Another inclusion that I had put in contract was that the slab be left for 7 days with formwork attached and additional curing methods being used prior to framing being commenced. A client shouldn't have to do that as the NCC 2015 includes Quote "Concrete must be placed, compacted and cured in accordance with good building practice." Why should a client need to contract good building practice? I know of many examples of builders, especially volume builders that commence the framing a day or so after pouring slab and concreters removing the formwork at the end of the pouring day. How does that help with the hydration of the concrete? 7 days of approved curing with form work in place should be a good building practice used in my opinion and that of my daughter's boyfriend, a concreter of 8 years experience. There is little enforcement of good building practices, just a builder's integrity and reputation. I read about this in Homeone all the time. Quality workmanship is hard to find. Even a client of a builder for a budget house being built should expect good building practice. Re: Waffle pod Void height. 10Jul 12, 2015 9:10 am mgilla Goody contrary to what your daughters boyfriend may say, I seriously doubt there has been a house slab poured this side of the Y2K bug that has had the boxing left on for 7 days. I agree with you mgilla but that doesn't mean that the practice of doing that, that is leaving the form work in place and employing additional curing techniques, isn't in accordance with good building practice. It is not done for reasons of expediency and cost saving measures I believe. Maybe a concreter of a lifetime experience in the trade like forum member onc_artisan can comment on the practice and give an opinion on good building practice when it comes to house slabs, curing and the 2015 NCC stated requirements. Edit. I just found this informative article. http://www.holcim.com.au/products-and-s ... iques.html Adequate curing sounds like good building practice to me and experts alike. It is a shame that bad building practices are employed by many builders, so many that it appears to just be the norm thesedays. Re: Waffle pod Void height. 11Jul 12, 2015 10:13 am goody59 For those that know, what should the waffle pod void height be in Victoria for a H2 site? For those building on H2 site what did they have your void height at when your waffle pod slab was done? 300mm or 375mm or something else? The polystyrene void has no stiffness irrespective of depth, It is the concrete stiffness(EI) and cross sectional area of steel that matters The design of foundations are very complex and the codes are based on simplified/out-dated empirical test results that builders are happy to use, IMO there is no one size fits all as the design for difficult sites should be left to computer simulations and engineers.The min design standard should always be checked. goody59 Slab top thickness- 85mm minimum. Who opted for 100mm and why? What about the MPa of your concrete. Did you get 20MPa or 32 MPa? Upgrading steel and concrete stress grades,thickness, bar sizing,etc costs little, it is the labour that costs and a lot of builders seem to think they can charge what they want..if you get my gist Projects need to be optimized and performance values checked, eg, max value Vs (min) cost, max span min Vs Stiffness. Ive said it many times an extra rebar costs $2/m, What matters is Where, Why, How and When it is placed. goody59 What about the steel reinforcement bars around the edge of the slab N12 or N16? (I know SL92 mesh required for slabs greater than 20 metres now for residential). Here is a simplified example of Optimization Steel is designed by engineers using Cross sectional area mm^2, steel is placed by the steel fixers per tonne/ which equates to $/hr. Since there are fewer N16 bars per tonne than N12, it should be quicker to placed and the builders pays the concractor less for fixing...is that savings ever passed on to the client? Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Waffle pod Void height. 13Jul 12, 2015 10:39 am goody59 .... The foundations of my new house are of the most concern out of the whole build for me. Me too.Thats why I advocate talking to an engineer first on difficult builds, he will give you the big picture, when armed with that look at the design/build. I can assure you your builders costings will always be cheaper before you sign any paperwork and hand over monies..get quotes and make them sharpen the pencil and avoid surprises later on. Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Waffle pod Void height. 14Jul 12, 2015 11:15 am StructuralBIMGuy, I got an email from my Builders it included a detailed attachment of preliminary engineering for my build. The email from my CSC also had this in it - "Please see attached preliminary engineering which has now been issued for your house. The engineers have recommended additional N12 bars as per below comments. Therefore, I would like to recommend additional top bars around the perimeter of the slab to counteract any potential slab heave in the scenario of a leaking drainage pipe etc. The additional N12 bars denoted on the plan attached are additional anti heave stiffening around the perimeter of the slab, in the case of a pipe leaking. " Does that make sence? Can I ask your opinion if the additional bars are recommended then wouldn't they be in the final engineered specs? Is it something extra that my builders may ask me to pay for? I am sure I will know if that is the case this week as I am ready to let the build begin after exploring a contractual option of slab upgrade if I want. I was looking at paying for a 100mm top versus 85mm top and paying for 32MPa versus the engineers 20MPa in preliminary engineering. The specs have my mesh as SL92 already as my slab is 22 metres long approximately. Regards Re: Waffle pod Void height. 15Jul 12, 2015 11:46 am Trust your Engineer's recommendations only he can advise you on varying specs..upgrading anything on site or prior to going to site cost$ extra over.... Unfortunately that favours the builder.. discuss these costs with your builder. BTW most engineers are approachable if you have the engineers name and ask him questions specifically to slab optimization & stiffness, I know some builders dont like their clients contacting the engineer..I dont have a problem with that Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Waffle pod Void height. 16Jul 12, 2015 11:54 am StructuralBIMGuy Trust your Engineer's recommendations only he can advise you on varying specs..upgrading anything on site or prior to going to site cost$ extra over.... Unfortunately that favours the builder.. discuss these costs with your builder. BTW most engineers are approachable if you have the engineers name, I know some builders dont like their clients contacting the engineer..I dont have a problem with that That will be MB from Intrax Melbourne. Intrax also were engaged by Simonds for the soil test and land contour survey. They also do the drain plans too. I guess Simonds like Intrax for their engineering and investigations. Anyway, thanks for your advice and opinion. Re: Waffle pod Void height. 17Jul 15, 2015 11:10 am StructuralBIMGuy Trust your Engineer's recommendations only he can advise you on varying specs..upgrading anything on site or prior to going to site cost$ extra over.... Unfortunately that favours the builder.. discuss these costs with your builder. BTW most engineers are approachable if you have the engineers name and ask him questions specifically to slab optimization & stiffness, I know some builders dont like their clients contacting the engineer..I dont have a problem with that Hi StructuralBIMGuy, Well I guess Simonds agrees with you. I had been asking them for some pricing for the recommended extra steel, the extra 15mm of slab top height and going with 32MPa instead of the 20MPa. The builders have just sent me a request to call engineers directly to determine the best way to move forward with my options then have the engineering finalised for the price adjustment. I agree and I am waiting for engineers to call me back. The only drawback I see is that the cost of options would be determined after choices in options are made. I still feel it would be money well spent in slab upgrade choices if my foundations are better up to the task of supporting my house on the H2 site trouble free for many, many years to come, not just the next 7 years. Re: Waffle pod Void height. 18Jul 15, 2015 4:31 pm Just finalising the decisions made after discussing my options and the engineers minimum requirements and recommendations regarding the waffle pod slab. It was decided to 1. Increase slab top to 100mm instead of 85mm 2. Use 25MPa concrete instead of 20 MPa. The engineer wasn't keen on using 32 MPa for some reason but that is an engineering decision and made for a reason so I am happy to comply of course. 3. Include the additional recommended N12 Bars in the top of the slab. The final engineering drawings will be completed by Intrax now and the pricing of the extras done by the builders- Simonds Homes and then the build can begin. Re: Waffle pod Void height. 19Jul 25, 2015 3:47 pm Pricing complete and variation now signed. 100mm top on waffle pod slab, 25MPa concrete, curing under plastic for 7 days and a heap of extra N12 bars places at required locations in the slab for extra strength. Build starts next week. This thread ended now and further posting in my house construction thread. 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 9841 Not sure if that works? I was told the issue is the headspace clearance requirement on step 4. My builder is proposing shifting the beam 310mm towards the kitchen...I'm… 2 2500 To me, that's what it looks like: poor backfilling and/or compaction. The width is about 1000mm maybe. That conduit in the photo is for the NBN. The water is about… 4 8038 |