Browse Forums Building A New House 1 Mar 25, 2015 8:01 pm Hi all, Getting to the nitty gritty of our build. Hopefully will have a slab in 6 weeks.... Had a good read of final engineering - N20 concrete is mentioned but it is not specified clearly - we are a P site with ED soil. Can't find too much helpful information about house slab concrete compressive strength required - I can find info on n32 where machinery is being moved on a slab eg commercial/sheds but what about for house slabs? Want to ask builders/engineers to clarify this but want some info up our sleeve if any one has it eg onc building expert... I looked up our old slab (2009) HD site - n20 concrete.... I don't want to worry for nothing but don't want to be complacent/ignorant/blindingly accepting either. Re: Concrete MPA 2Mar 25, 2015 9:02 pm All slab design is based on both the strength of the concrete and the amount of steel, which can be used in either tension or compression. There are no reasons why N20 wouldn't be suitable if the design meets the requirements of the design code. On a personal note I'd be quite happy to see N20 on the drawing but have 25 delivered so it should still be strong enough if poor laying practices occured resulting in lost strength. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Concrete MPA 3Mar 26, 2015 7:58 pm Thanks bashworth, that's reassuring to hear. We are going to question raise the question with engineers. We are having pre slab inspection and may have an engineer present whilst slab being poured. To my understanding early saw cuts are to control shrinkage cracks, so doing them now would be pointless. Control joints may reduce ugly cracking during periods of soil… 3 9831 Hi all I need a guidance on how far I need to space expansion joints in the concrete driveway and its type (keyway/foam.) Contraction joints are at 3m max for a 125 slab. Thanks 0 10929 |