Browse Forums Paving & Concreting Re: Control joints in waffle house slabs - Where are they?? 21Apr 08, 2011 7:33 pm Ok so the upturned slabs look like thiis: On the left is an upturned 'raft' slab and on the right is a 'Waffle' slab. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ All those corners make it more likely to crack due to volume changes. What are volume changes? Volume changes are when the thickness of the concrete change from 1 size to another. Does that make sense? Now if I wanted concrete to 'shape' I would change the volume to suit the shape I wanted. Please note it matters not which slab I go for we build to an engineers design... I know which I would prefer ... and some places 'MIGHT' do better with a waffle slab. Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 23Apr 11, 2011 9:14 am Thanks for the pic onc, that makes both of your points easy to understand. From Aiah's view I can see how the waffle looks stronger as the grid gives the impression of being very well reinforced. Kind of the same as an engine block with more ribbing around it. (for those that know think Toyota early 4AGE 86kW blue top 3 rib VS Red Top 88kW with 7 ribs) Thank you both for your input I don't know anything about the specific volume changes but again i have an idea. Re: Control joints in waffle house slabs - Where are they?? 24Apr 11, 2011 9:30 am The raft will have a slab thickness of 100mm + the waffle will have 86mm + and the mesh is to sit somewhere in the middle. The key to this is curing the slab. Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 26Apr 11, 2011 7:54 pm ^ wow ... Just thinking of some claims that "slabs are over-engineered anyway" vs. "if it's working, don't touch it" Anyway, this is what I found today on one concretor's site and remembered this discussion, but didn't have time to update this. "Waffle Pod Systems Polystyrene rafts and waffle pods have revolutionised the concreting industry over the last decade. A waffle pod system can save considerable money – site preparation is much simpler and there are significant savings in the amount of concrete used. The polystyrene raft is also a great insulator, reducing heat transfer through the floor." "Stiffened raft slabs The more traditional stiffened raft slab is sometimes preferred by builders, particularly for more complex residential housing or commercial construction. It is sometimes the only way to achieve the flexibility and strength required." My signature is distracting people from my wise posts ... Re: Control joints in waffle house slabs - Where are they?? 27Apr 11, 2011 8:22 pm I don't understand the reasoning behind insulating the slab Why would we want to do away with the advantage that we get from 'earth' contact. A constant 15 c seems crazy to me but hey I am just a pleb. How does it save time and concrete BTW? Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 28Apr 11, 2011 8:28 pm I have no idea onc, this is a straight copy from their site. I guess that's how they interpret these 2 types of slabs?! I did see some nice engineering / official descriptions of these 2 slabs aaaages ago, but don't want to even try to reproduce it here as my memory is not that good My signature is distracting people from my wise posts ... Re: Control joints in waffle house slabs - Where are they?? 29Apr 11, 2011 9:28 pm waffle slabs are quicker on the bases there is less work involved in the slab. Also there is less risk with trenches filling with water if it rain which can cause further delays. In terms of saving concrete this mainly due to having less waste, that occurs when trenches are made slightly wider and deeper than they need to be. Re: Control joints in waffle house slabs - Where are they?? 30Apr 11, 2011 11:44 pm A good job for monkeys With 1 huge screed that vibrates .. just get someone else to do the set out and a slab should be cheap as chips. Us granos are a dying breed.... anyway it only takes a week or so and yer an expert apparently Soon they will do away with concrete all together. And soon we will have stick homes that blow over in the wind Just like in the US... good for reconstruction work if ya want it. Anyone noticed how the old homes that were made of bricks and mortar are still standing??? Geez some are 150 years old.. how does that work??? Ok off the soapbox Turrah Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 32Apr 14, 2011 11:23 pm Taking a while to phase them in ... better they phase them out ... all the ones I have seen have been sh!t... Foam poking out the side, cracks to numerous to contemplate repairing, slab thickness of 50 mm to 95 mm, Mesh poking out.. should I go on? Nup it is a waste of time me crapping on... Time will tell. Where you are coming from is where you are going to... Re: Control joints in waffle house slabs - Where are they?? 34Apr 21, 2011 4:33 pm I was talking to an engineer today, he said he will only design a raft slab if a client requests one and they cant be talked out of it. One major builder he works for uses the raft slab as a selling point, not for any reason other to capitalise on peoples fear of having their house sitting on polystyrene. I also asked him about the volume changes Onc, he shrugged it off, saying each volume change creates a "T" beam, having so many of them makes the slab very very rigid. Re: Control joints in waffle house slabs - Where are they?? 35Apr 23, 2011 10:22 am ...to each his own... happy Easter/ Long weekend to everyone Where you are coming from is where you are going to... 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. I think I did… 0 7465 my suspicion - some builders, they do usually make 'odd' settings in their site plan / pricing as their standards - being hopeful that first - the initial price is… 9 2475 The Soil classification has little to do with piers. The purpose of the classing of the soil is to identify the clay content and the "average expected range of movement… 2 9854 |