Browse Forums Building A New House 1 May 14, 2008 8:48 am Hi all,
We have recently signed with a builder in South Australia. I have spoken to the building inspector who we are planning on using and he said that it is important that the slab is covered with a plastic membrane for at least five days after the slab is poured to minimise the chance of cracks appearing in the slab. We have spoken to our builder about this and they are refusing to cover the slab and say that if we do this we could void the warranty. Firstly, I was wondering if there are any builders/experts in this area who could comment. Our builder is saying that the slab is covered with a spray solution to prevent the top drying out too quickly but the building inspector says anything other than plastic sheeting is not acceptable. Secondly, I know that there have been other posts about fine cracks in the slab on here and I was wondering what others have been told by their builders/inspectors when they queried it. Lastly, has anyone else recieved info from their building inspector that is anything like mine. Thanks in advance. I didn't really building would be quite so involved. Re: Cracks in slab 2May 14, 2008 6:16 pm Hi Craigburn,
my advice would be to inform your inspector (I assume you meant consultant) that it is 2008. If you are polishing your concrete, then this is not a bad practice but assuming, which one should never do you are using the typical floor coverings that suggestion is one of the more crazier i have heard of in a while. Concrete has additives, concrete cracks, but the rio in the slab holds it all together. Hairlines are fine, heaving definately not. Good Luck SFSG Re: Cracks in slab 3May 14, 2008 10:06 pm Hate to disagree on some points...but I will...
sofar_sogood my advice would be to inform your inspector (I assume you meant consultant) that it is 2008. Impermeable membrane curing is still an acceptable method of curing. However, it is generally not used in domestic situations. Maybe be more standard in SA where it is hotter and drier although I think even SA is cool enough at this time of the year. sofar_sogood If you are polishing your concrete, then this is not a bad practice but assuming Plastic sheeting is problematic with surfaces where concrete surface quality is important. If the plastic is not secured you get air draughts or if it's wrinkly in can cause uneven surface curing. For decorative finishes it is recommended that and membrane be supported clear of the surface so that you get an even cure. sofar_sogood which one should never do you are using the typical floor coverings that suggestion is one of the more crazier i have heard of in a while. Well not crazy, just not usual practice in domestic construction. That doesn't make it "bad" practice. sofar_sogood Concrete has additives, concrete cracks, but the rio in the slab holds it all together. Hairlines are fine, heaving definately not. Yep hairline shrinkage cracks are more than likely to occur. Structural cracks where there is slab movement immediately post construction would be unacceptable. mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: Cracks in slab 4May 15, 2008 7:48 am I agree with SFSG to remind your inspector that it is 2008 (and perhaps look for someone else to replace this inspector?).
In structural works (granted not domestic) - will now never see the old methods of covering by plastic sheeting or the old hessian alternative for curing concrete. Curing oil (presum what you builder is referring to as a spray solution) is always used and carries out the function much more effectively and completly than covering by plastic. In Structural works we are often talking about 50MPa concrete and not the typical house concrete of 20 MPa, including concrete used for water retaining structures, (tanks, pump cells etc) ... ie it is much more sensitive to cracking than a house slab. The only question in my mind is to make sure the builder does actually spray the slab with curing oil! My experience is that in the housing industry versus structural / engineering construction the lack of formal QA means many more shortcuts are taken. Re: Cracks in slab 5May 15, 2008 9:03 am Hi all,
Thanks for your comments so far. Based on your responses, I'm assuming all of you have some involvement in the building industry to make the comments that you have, so thanks for your feedback. The slab hasn't been poured yet and we have only just started the contract process so it is likely to be much warmer when the slab goes down (Oct/Nov). I can't believe how hard this whole process is if you don't have any understanding/experience in the building process/industry. I feel like I'm at the mercy of whatever other people tell me until an alternative person advises otherwise. Has anyone used an inspector in Adelaide that they were happy with? No-one that I know has built a house recently and used an inspector and based on the feedback I should be finding another inspector. I am surprised because they are quite a large company and have been around for a long time. Any suggestions would be fantastic. I think I'm going to go crazy before this is over . Re: Cracks in slab 6May 15, 2008 10:00 pm just started The only question in my mind is to make sure the builder does actually spray the slab with curing oil! My experience is that in the housing industry versus structural / engineering construction the lack of formal QA means many more shortcuts are taken. Re-reading my response I noted I didn't mention the use of curing compounds which of course are acceptable if applied correctly. They are generally pigmented and therefore offer a "tell" as to whether they have been applied, of course whether they have been applied correctly is another matter. Having said that I don't think I've seen any concrete contractors applying these compounds to slabs in our estate (Western Melb). As JS pointed out as there is no formal documentation, it's difficult to track. Perhaps the inspector is recommending the older methods of curing because it's easier to tell whether they have been done? mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard The CSIRO BTF18 explains differnt types of cracks and what "normal" is Google this and the top result is actually the latest version. You normally have to buy this from… 9 9319 The spacing of the studs looks pretty large especially for a load bearing wall. 3 11116 It sounds like you have a crack in your garage where the wall meets the ceiling, along the shadow line on the… 0 17197 |