Browse Forums Building A New House 1 Mar 02, 2010 2:34 pm Hi All, Firstly let me say this is my first post on here and I thank everyone in advance for any input provided. I am nearing settlement on a block of land (flat block, 650m2, no easements, in an already established street with most of the fencing already done.) I have been looking at Aaron J Homes as a builder who provide "M" class foundation with engineer designed "M" class waffle slab, termite protection and 300mm site fall to building area as standard inclusions for site costs. After reading about the pros and cons of waffle slabs, I was hoping someone could enlighten me further regarding this matter? I've read that waffle slabs are popular, cheaper to implement and if engineered properly stronger than raft slabs? Then, on the flip side I've been told that vermin can get underneath the slab and eat away at the polystyrene waffle pods significantly weakening the concrete? Am I going to fall through the floor one night whilst watching House in my living room? Another question...Is there any way of obtaining Soil Test reports from neighbouring houses? And lastly, if my soil test came back suggesting an "S" class foundation was sufficient, what sort of money back are we talking from the builder given that they allow for "M" class in their inclusions? Thanks again for anyone who takes the time to respond. Re: soil test and type of slab? 2Mar 02, 2010 5:11 pm Generally most builders include 'M' class slab in new home prices. This is the basic site works for a perfect block; ie, FLAT, No Fill, etc... In reality most new estates have a level of earthworks that means some fill, maybe crossfall that needs to be cut and filled, etc. This means in reality at best you may ONLY have a modified class M slab but you would still be up for additional site costs. Our site and engineering report is for a 'P' class slab. My sister is an engineer and I asked her to explain and this is what she said..."They’re quite common – they’re cost effective because less time is spent preparing the site to lay the slab (saving one to two days on slab construction). The term “waffle slab” isn’t all that creative – they look like the kind of waffle you’d toast and eat. The edge beams and beams for load bearing walls are founded into good dirt (for you, because it’s a class P site, it should be into “natural” soils (i.e. below the fill they placed across the development), they may do this with bored piers rather than perimeter edge beams), the ribs sit on the ground and the ‘voids’ are filled with a very high density polystyrene (rather than soil, which is the traditional method). The polystyrene provides much better installation than soil. You can get your own soil and engineering tests done, you could ask your neighbours to see their soil and engineering report, or if the developer did a soil and engineering report, you may be able to get a copy of that. We're building in Sandhurst, and although the developer did a high level of compaction and thus recommended a modified class 'M' slab for construction, most builders are putting in class 'P' slabs so that's what we're having. And our block is practically flat. If your soil and engineering report comes back recommending class 'S', you'll be paying more for site costs, not less. I used to have a list of the different slab classes and what they mean. I'll try and post it if I find it. Re: soil test and type of slab? 3Mar 02, 2010 5:39 pm My building inspector said that waffle slabs are much easier for the builder to get right. Most waffle pod slabs he inspects are pretty good, whereas MOST raft slabs he inspects have issues such as insufficient waterproofing. Metricon Riva 33 - http://herlihy-riva.blogspot.com Site start 15/03/2010 - Handover 23/12/2010 9 months and 8 days (284 calendar days) from site start to handover Re: soil test and type of slab? 4Mar 02, 2010 5:46 pm Here's a link to a website that describes the different slab classes, and slab construction methods. Apologies for thinking type S is more expensive than M! I was relying on memory...not a good thing to do! Regarding a refund from your builder if you end up with class S...good luck. http://www.renovationrobot.com.au/found ... tions.html Re: soil test and type of slab? 5Mar 02, 2010 7:59 pm Thanks for the responses guys....much appreciated. I'm hoping to get away with an M class foundation and not incur any additional site costs. I am building in Pakenham, Victoria. The land was previously cattle grazing farmland, flat with a good layer of topsoil cover. Re: soil test and type of slab? 6Mar 09, 2010 5:52 pm hi lindrum-52 we are building in sandarra which is the estate opposite sandhurst and our site was classed as a P. We are getting a waffle raft slab,here are some of the specifications slab thickness 85mm internal rib width 110mm external rib width 300mm rib depth 310mm slab fabric SL-82 it mentions perimeter edge beams but not piers whats the difference. I have slab engineering & footing details in front of me but not sure at what Iam looking at .Before they pour the concrete is it imperative that the structural engineer be present ? How do I know if the form works are correct and in the right place.What are the chances of something going wrong ? Hi Building Expert, Thank you for the feedback, much appreciated, there is also a code of conduct for building surveyors which they need to follow as well. I am looking… 4 3660 Thanks for your reply. I will just wait and see I guess. Trying to get some more information from our builder. 9 30243 We were lucky in that our old house was so small (86 square metres) compared to the new house, they were able to take enough readings around the old backyard house before… 8 37097 |