Browse Forums Paving & Concreting 1 Dec 26, 2010 12:06 pm Hi all Have just removed a big spa fto turn the space into an entertainment area. I've attached a pic which I hope will explain things but basically the house is built on a slab and the slab is covered with paving. The spar was held in by a hefty retaining wall, the bottom of which was on the slab itself and therefore lower than the paving top. The drop from paver to slab is about 7cm. The slab extends a few inches all around (to support the brick retaining wall) and after that the middle was dug out which is where the lower parts of the spa went. That area is now filled with loose sand and some small pieces of rubble. What we want to do is concrete the area where the spa and retaining wall was, bringing the floor up to the level of the pavers. This will then be covered with a new floor, probably made out of rubber tiles, that will extend a little way onto the pavers themselves. The back two sides of the area will have benches built into them. Therefore, finish isn't a problem here because the floor and the back two walls will be covered; as long as the floor is flat, it's fine. My questions... 1. I'm planning to use the lip of the pavers and the back two walls as a form, basically tipping the cement in and levelling it, bringing the concrete up to the level of the pavers. Anyone see a problem with that? 2. Can I put some rebar down over the sand and pour onto that or do I need to dig the sand out? 3. ANy specific type of concrete I should use? 4. How thick does the concrete need to be? 5. Would it be best to concrete in two stages, first bringing the floor up to the level of the slab and THEN concreting to being it up to the level of the pavers? I would really like to do this myself but if you folks think thats unwise, I will listen. Didn't come here to ask your advice so as to ignore it I have a feeling I'm making a mountain out of a molehill, but I hope not. Apologies if this is badly expressed or explained and I'd be happy to supply any other info if you need it. Thanks! Here's the pic... Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Re: Small Concreting Job - Confused Beginner! 2Dec 26, 2010 1:46 pm 1 I'm planning to use the lip of the pavers and the back two walls as a form, basically tipping the cement in and levelling it, bringing the concrete up to the level of the pavers. Anyone see a problem with that? YOU WILL NEED AN EXPANSION JOPINT OF 5-10MM OF FOAM AGAINST THE WALL. ALSO BREAK THE BEDDING CEMENT BACK TO THE EDGE OF THE PAVERS YOU ARE GOING TO LEAVE. 2. Can I put some rebar down over the sand and pour onto that or do I need to dig the sand out? FOR THIS LEAVE THE SAND IN USE MESH RATHER THAN REBAR AND PUT ON CONCRETE SADDLES SO THEY ARE AROUND 40MM FROM TOP SURFACE 3. ANy specific type of concrete I should use? 25MPA CONCRETE WILL BE FINE THE PREMIX COMPANY WILL UNDERSTAND 4. How thick does the concrete need to be? FOR THIS 70MM WILL BE BEST 5. Would it be best to concrete in two stages, first bringing the floor up to the level of the slab and THEN concreting to being it up to the level of the pavers? SINGLE STAGE WILL BE BEST 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: Small Concreting Job - Confused Beginner! 3Dec 26, 2010 2:17 pm Understand the foam and the mesh. Will break the concrete back as far as I can, as well. Thanks for the advice on type and depth, too. Much appreciated. Not sure what you mean by concrete saddles, though. Could you elaborate for me? Re: Small Concreting Job - Confused Beginner! 4Dec 26, 2010 2:47 pm Saddles are small plastic devices for supporting reinforcement in position. You should be able to get them from reinforcement suppliers. You can use bits of broken concrete to stand the mesh on but the key thing is making sure the mesh is in the middle of the finished concrete. 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: Small Concreting Job - Confused Beginner! 6Jan 12, 2011 9:23 am Actually if you place the mesh in the middle, it will be at it weakest, it is best to place nearer to the top or bottom but maintaining sufficient cover. Concrete is strong in compression and weak in tension. Placing it in the middle allows for flex both up and down (tension on top and bottom) placing it higher gives it strength from tension from rising ground below. if you place it nearer to the bottom it will be better for heavy loads on top such as a spa or car as it wants to bow downward and create tension on the underside of the slab. Re: Small Concreting Job - Confused Beginner! 7Jan 12, 2011 9:46 am You should also have starter bars going from the old concrete into the new concrete which laps the reinforcement being placed. If you don't then in the goodness of time the new slab will move independently of the existing slab and you'll end up with an ugly lip. mmm....donuts Homer Simpson 1956- Links: Site Costs Ready Reckoner | H1 Addiction Medical Advice | Château TDL: The Backyard Re: Small Concreting Job - Confused Beginner! 8Feb 07, 2011 10:13 am as above^^ If you don't dowel the joint you might end up with sand jacking causing the lip TDL is talking about. Where you are coming from is where you are going to... I posted the floorplan on Houzz.com forum and got some really good ideas and advice from people there. Then we reached out to a couple of renovation companies and one… 5 6761 Last year I had a gas leak at my house. 3 days later, I have about 1 sqm of my exposed aggregate paving broken up. I am not sure how to go about getting it repaired… 0 8111 It will be neat but you won't have much freeboard. At least they are not weep holes. Are you in a high intensity rainfall region? The regulatory slope is only required… 3 5254 |