Browse Forums Building A New House Re: Does H2 site classification require slab piers? 3May 03, 2018 7:12 am Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Does H2 site classification require slab piers? 6May 05, 2018 9:16 am Designer,Engineer (Civil,Const & Envir),Builder,Concrete & Masonry Contract.Struct Repairs Re: Does H2 site classification require slab piers? 9May 15, 2018 10:53 pm Thank you very much for your such detailed explanation, Geo1. It allays my significant concerns on the absence of pier in my H2 slab. Geo1 The need for piers has no reference to your slab classification i.e. Class, A, M, H1, H2 or E. If your site was classified as Class P, then "in certain instances" you may need piers. The "normal" AS2870 site classification mentioned above (other then Class "P"), are purely a measure of differential movement based on "normal" seasonal moisture variations. i.e Clays when dry will shrink/settle and when wet will swell/expand. You can require piers on any site classification above it will really depend on your site constraints and engineer. By classifying a site as Class H2, the site has been classified as having a "Very High" ability to shrink/swell in changes in soil moisture content. This still does not have anything to do with piers. Piers will only help you in soil shrinkage/subsidence, and the structural stiffness deals with the swell hence you pay for a thicker slab with thicker steel. H2 will require N16's rib bars and edge beam and SL92 mesh. Most QLD builders will reluctantly pier houses unless needed. i.e. Trees within zone of influence, uncontrolled fill, retaining walls, easements, potential pools etc Most NSW builders will pier regardless of understanding mainly because engineers in NSW believe piers solve all problems. Most builders in NSW will construct what they call "construction piers" or 450mm dia 500mm - 1000mm deep regardless of site classification in order to deal with small lots and service pipes running either through the slab or parallel to slab within a short distance. I agree with StructuralBIMGuy above, this is really builders margin 101. You should really be asking the builder "why are the piers required? Is it because of services, easements, fill, bearing pressure etc. How good is Simeon?! Always taking time to help others out! Wish we were building in NSW and could work together. Thanks for all that you do! 7 6550 DIY, Home Maintenance & Repair That’s very helpful information. Will find out more from there. Much appreciated. 11 13430 3 1364 |