Browse Forums Paving & Concreting 1 Apr 05, 2011 2:35 pm Just wondering. Driveways, paths and basically any other slabs have them, but not house slabs (at least not in waffle pod slabs). Why not? House slabs can crack too. What is there to induce the cracking at a controlled location?? My signature is distracting people from my wise posts ... Re: Control joints in waffle house slabs - Where are they?? 2Apr 05, 2011 2:59 pm Lex, its because slabs are structural, where as driveways re not. You are better off having 1000 small hairline cracks then one 2 mm crack in one spot that can cause a brick wall to open up. Re: Control joints in waffle house slabs - Where are they?? 3Apr 05, 2011 4:45 pm BSTAR is right the slab will have lots of hairline cracks (which are held closed by the reinforcement) so there will be some movement in the slab. You should allow for this by having movement joints in the brickwork 5m so the slab movement doesn't result in cracking of the brickwork at the mortar joints. 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: Control joints in waffle house slabs - Where are they?? 4Apr 05, 2011 7:42 pm I don't think I understand . I thought that house slabs can have bigger than hairline cracks and that it would be more critical to provide a "planned" path in a house slab than in, say, driveways Where am I going wrong with this?? Would installation of rigid floor coverings (like tiles) also be a part of the story? But this doesn't make sense, since patio slabs have CJs ... My signature is distracting people from my wise posts ... Re: Control joints in waffle house slabs - Where are they?? 5Apr 05, 2011 7:55 pm It is permissable for house slabs to have slightly bigger than hairline cracks, but the majority will be hairline. The reinforcement holds the cracks closed With a house slab a series of fine cracks at say 1m intervals is better than having a 'fold' at a formed construction joint. With regards to floor tiles the best way to fix them is to use a flexible adhesive rather than one that sets rigid. This flexible adhesive allows those very minor movements of the concrete slab. The other option of course is a flaoting floor. 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: Control joints in waffle house slabs - Where are they?? 8Apr 06, 2011 2:04 pm Australian standards have just been revised concerning waffle slabs, there will be more controlled jointing in slabs over 30m long. They are basically beefing up the minimum specs for waffle slabs .. M class slabs will be using the old H class design...ect I have seen a handfull of waffle slabs that have key joints through the middle, not many though. Re: Control joints in waffle house slabs - Where are they?? 9Apr 06, 2011 6:34 pm Is that right, increasing the standards?? What for?! Just the other day I heard (for the millionth time) that the standards for slabs are already "overengineered" - aren't we lucky ... Double Lucky !!! My signature is distracting people from my wise posts ... Re: Control joints in waffle house slabs - Where are they?? 10Apr 07, 2011 6:29 am It will be good for the steel industry I spose. Its going to add a few grand extra in materials for any slab ... more work for the granos to I guess, tho I doubt they will get anything more than a sore back and earlier retirement. Re: Control joints in waffle house slabs - Where are they?? 11Apr 07, 2011 9:43 am no comment is best, you guys can work it out. Is anyone but Aiah in the concrete placement industry? Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 12Apr 07, 2011 4:36 pm onc_artisan :th: no comment is best, you guys can work it out. Is anyone but Aiah in the concrete placement industry? Only for over 30 years 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: Control joints in waffle house slabs - Where are they?? 13Apr 07, 2011 4:51 pm Still placing concrete? You must have sore knees and a crook back? Do we understand why control joints in wafflepods are coming into play? Could it be the volume changes about every metre? Are wafflepod slabs all that they are cracked up to be? pun not intended. Or is it that we need some more time to evaluate them? Sorry about the quick rant but it bugs me. Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 14Apr 07, 2011 5:13 pm I don't place concrete any more apart from round the garden. I've designed, supervised, and maintained plenty for airports and more lately for water projects. Trouble with any large slab (such as over 30m long) is the amount of steel required to control cracking gets excessive. (In water retaining concrete tanks you start to wonder if there is room to get the concrete in) High cost for steel and fixing and not enough room for the steel in house slabs unless you start placing the pods further apart to make the concrete thicker. I've had ordinary slabs in the past but my present house is on a waffle slab. I've no real preference so have just gone along what my builder feels comfortable constructing 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: Control joints in waffle house slabs - Where are they?? 15Apr 07, 2011 8:52 pm Was the waffle pod design was introduced in Australia and pioneered by a volume house builder to reduce their costs and increase profit whilst appearing to be an option for home buyers to reduce costs? Re: Control joints in waffle house slabs - Where are they?? 16Apr 07, 2011 9:14 pm xs freon and waste oil perhaps. Does anyone have a control joint in their slab? I did see one today that divided a house and made 2 strips of concrete 4 mtrs wide and 10 mtrs long. ... and guess what a crack every few metres If anything they divided the slab the wrong way Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 17Apr 07, 2011 9:33 pm chrisandkate Was the waffle pod design was introduced in Australia and pioneered by a volume house builder to reduce their costs and increase profit whilst appearing to be an option for home buyers to reduce costs? Most likley... much has changed since the first waffle slabs were laid... engineers are working out what works and what doesnt as they age. There are first generation waffle slabs near my house... they havnt fallen down yet. While i respect Onc-Artisans experience and knowlage in all things concrete, Id still opt for a waffle slab over raft slab any day... Re: Control joints in waffle house slabs - Where are they?? 18Apr 08, 2011 7:27 am I accept your opinion as everyone knows my opinion anyway. Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 19Apr 08, 2011 1:41 pm Aiah Id still opt for a waffle slab over raft slab any day... Why is that? I ask because my new house is getting a raft type slab. Doesn't bother me as I have not much idea why they chose it. But I assume factors could be: - the level of fill required - the extra tree root barriers required - the fact that we removed a house on a slab to build a new one - Builders preference - Builders experience in area and with this particular design of house as it was their own (smallish builder) I'd like to know why you prefer one over the other though Re: Control joints in waffle house slabs - Where are they?? 20Apr 08, 2011 7:08 pm chrisandkate Aiah Id still opt for a waffle slab over raft slab any day... Why is that? I ask because my new house is getting a raft type slab. Doesn't bother me as I have not much idea why they chose it. But I assume factors could be: - the level of fill required - the extra tree root barriers required - the fact that we removed a house on a slab to build a new one - Builders preference - Builders experience in area and with this particular design of house as it was their own (smallish builder) I'd like to know why you prefer one over the other though At the end of the day both waffle and raft slabs achieve the same thing. Neither way is the wrong way to do it. I prefer waffle because the system makes more sense to me. Hi All, First time poster. I was hoping to get some advice on villaboard installation within a bathroom. I have installed villaboard before, in a laundry. 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