10 March 2020. The top of the new concrete would have to be a max of about 5-6 inches above existing concrete, butted against wood sheathing. re: Tying New Concrete to an Existing Foundation - Yes or No? You can cut the wood yourself with a circular saw. How do I know if I should go with an extension or a brand new porch? He wants to put a small layer, "Thanks for the helpful advice. ", we wanted, so we needed to figure out how to fix it. The mixture of water and cement is made in slurry and spread over the existing slab to form a bonding coat between the old and new concrete to be laid. Pouring interior concrete slab over existing, cracked concrete slab [ 4 Answers ] I am turning part of my carport into a new living room. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. You may want to put screws in the wood posts halfway in, so they protrude an inch or two. It's about 8 feet wide. wikiHow is where trusted research and expert knowledge come together. Masonry Specialist & Founder, GO Masonry LLC. You may be able to rent a washer from them. Fine concrete looks smooth or has very small stones. Less is usually more with the scratch coat. There are are two things we need to discuss under concrete pouring. Their idea was to dig a footing across the front, and screw angle to the tile along the side wall and rear wall to keep the slab from settling. My back veranda, "It seems I follow those directions already, which is great for confirmation which swept and mopped up the existing, "My best friend asked his buddies to help him pour a slab for our homemade BBQ pit. Patch damages as soon as they develop to prevent them from spreading, and seal the new layer with a deep penetrating sealer to prevent water damage. For a walkway, raising the level by We have The mixture of aggregate and cement is mixed and poured it all into the existing concrete. A slab poured over an existing slab is more vulnerable to frost heave damage and cracks. The concrete is replacing a lawn, so when you get out of your car, you don’t have to walk on the grass. Disadvantages of Make sure no one is able to step on the concrete until it has finished curing. Oil and sap must be removed before new concrete can be poured. © 2009-2020 The Constructor. By signing up you are agreeing to receive emails according to our privacy policy. Get as much of it off the concrete as you can. Follow the manufacturer’s instructions to mix the TSP powder with water into a paste. I am making garden statues, that led me to finding this article. By the same token, if you attempt to clean the surface and the concrete just keeps breaking apart into bits of sand and gravel, replacement is your best option. Push the debris off the concrete surface or collect it in a bag to throw away. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. ", needs patching over, also and have been wondering for quite some time if patching over old cement worked. Use a stiff-bristled broom to knock as much debris out of cracks as possible. last month. Sorry, you do not have permission to ask a question, You must login to ask question. Make sure you clean everything immediately when you're done with it so the concrete doesn't dry. Concrete is one of the most versatile and best stone patio paving materials available for building a solid base or structure. I’ve owned my own concrete flatwork company for 35 years and been in the business for 40 years. Make sure the stakes are planted firmly in the dirt so the braces don’t fall as you work. If you don’t own a pressure washer, check home improvement stores in your area. It must be ensured that the braces are evenly spread which is can be done by running a bubble or string. ", "A lot of neat ideas that will make the job easier, keep up the good work guys! washer so that the hidden debris. This includes removing sand, dead leaves, and gravel. The foundation … It gives you a better chance at creating a strong, level slab. I have done this with an existing patio. I’ve grown my business from just specializing in concrete floors to being the only company in my area that specializes in concrete stamping, staining, floors, slabs, patios, decks, repairs, epoxy … The acid is strong, so dilute it first, mixing 1 part acid in 3 parts water. % of people told us that this article helped them. Set up wood braces to contain the concrete in a corner. For the thick concrete slab, a wire-mesh is needed on the braces to provide strength. Disadvantages of pouring new concrete over existing concrete. I now know it must be at least 1" and these steps must be followed. It is a dirt floor with 4" concrete. cleanliness needs to be done thoroughly, it’s recommended to use pressure I don't think we have 1" to spare. For tips on which type of concrete to use and how to build the perimeter, scroll down! Pouring a new layer of concrete over an existing walkway, patio or porch will raise the level by several inches. Another option is to use trisodium phosphate (TSP). If the slab runs up to a door, the raised surface may not provide the necessary clearance for the door to open. Here’s the catch – if the existing surface is somewhat in a structurally sound shape and elevating its height to a few inches won’t be a problem, you can certainly freshen it up with a new layer of concrete. If 1 end is closer to the string than another end, the brace isn’t straight and should be adjusted. I had a company give me an estimate. Wear protective gear, including a respirator mask. Use a chisel or jackhammer to remove damaged portions. My question is about pouring the concrete. Use the same concrete you plan on using for the final layer. The objective of proper preparation is for the existing concrete not to be a "base," but to "combine" or "be part of" the new. It is often included as part of the patching mix. A bonding adhesive is used in the concrete to ensure that the new concrete stick existing concrete successfully. Country You'll find a lot of useful information in two ACI reports: "Concrete Repair Guide," ACI 546, and "Guide for Concrete Floor and Slab Construction," ACI 302.1. Tying into an existing concrete driveway involves digging, spec-ing, sloping, pouring, and brooming. Then, install forms and continue building your wall as you normally would. ... Pouring new concrete next to old. Pouring Concrete over the Existing One. If your concrete is badly cracked, it may not be salvageable. The measurements acquired can then be used to estimate the amount of concrete required. You could, but it would be better to find out why your slab is not level and correct the underlying problem, lest your shed tilt in the future. You can also see it when you open the bag. with it. Cheers for the advice. Concrete work is best done on cool, dry, overcast days. Pouring concrete onto an existing slab or pathway will result in a concrete surface several inches higher than before. The top countries of supplier is China, from which7. The edge of the existing concrete that was sawed should be drilled and doweled so the new concrete won't separate, lift, or settle from the old concrete. Consult a professional to determine what needs to be done. By using our site, you agree to our. I am going to pour a concrete slab about 4 inches thick over the existing carport floor which is a concrete slab. In this article, correct concrete pouring according to ACI 304R-00 is presented. The same principles as above apply to pouring concrete over an existing concrete driveway or sidewalk. You won’t get a single, uniform slab, which can lead to bonding issues in the layers. ", https://www.bobvila.com/articles/how-to-clean-concrete/, https://www.concreteconstruction.net/how-to/construction/cold-weather-concreting-101_o, https://www.youtube.com/watch?v=k1XFWNT7pAM&feature=youtu.be&t=43, https://www.youtube.com/watch?v=zrcwuhsHCA8&feature=youtu.be&t=156, https://www.calculator.net/concrete-calculator.html, https://www.youtube.com/watch?v=80tifUtp-bM&feature=youtu.be&t=23, https://www.youtube.com/watch?v=zrcwuhsHCA8&feature=youtu.be&t=56, https://www.sciencedirect.com/science/article/pii/S0734743X16306364, http://www.cement.org/cement-concrete-applications/concrete-materials/aggregates, https://www.bobvila.com/articles/how-to-pour-concrete/, https://www.youtube.com/watch?v=L3g5mooTjaQ&feature=youtu.be&t=46, https://www.youtube.com/watch?v=L3g5mooTjaQ&feature=youtu.be&t=72, https://www.bobvila.com/articles/how-to-mix-concrete/, https://www.constructionprotips.com/jobsite-tips/pour-a-perfect-concrete-slab/, https://theconstructor.org/concrete/concrete-curing-compound-types/13478/, https://www.bobvila.com/articles/curing-concrete/, Aggiungere nuovo Calcestruzzo a Quello esistente, पहले से मौजूद कंक्रीट पर और कंक्रीट एड करें (Add Concrete to Existing Concrete), consider supporting our work with a contribution to wikiHow. Sweeping dirt’s debris over the existing concrete slab will allow bonding to take place. If the When setting fence posts, can more concrete be added over dry concrete in the hole? stubborn spots. Become VIP Member, Do you need to remove the ads? Difference between Flexible Concrete and Normal Concrete. How to Lay Concrete on Top of an Old Concrete Garage. This could prevent doors from opening and closing, cause misalignment with stairs or even create a trip hazard, so consider these issues when planning your project. No matter how strong a slab of concrete seems, it will wear out over time. I am a building contractor with 25+ years. If the slab underneath continues to move, the upper layer also eventually will move. If it isn't level or easy to work with, you may need to redo it before you can expand it. Concrete Around Trees. If my building has been rezoned and I need a 6-8 inch slab, is it possible to add a layer of concrete on top of the existing 4 inch slab or do I need to pour an entirely new slab for it to be a permanent fix? If, when pouring the concrete right up against the asphalt, you end up with parts of the concrete that taper or feather out to less than say about 1.5 -> 2.0 inches thick you will have trouble keeping the concrete in one piece. Take your time measuring. Thanks to all authors for creating a page that has been read 530,486 times. It may be better to "slabjack" the slab level (inject a product under the slab that will float it level) than to add a thin layer to the top that is prone to adhesion issues. Another way to test the boards is to run string behind them. structure. Concrete is a mixture of water and cement. These braces serve as a mold. When needing to pour a concrete slab durring a period of social distancing you sometimes have no choice but to do it yourself. Hope it turns out okay. The maximum thickness isn't an issue, but the minimum is. This is David Odell with Odell Complete Concrete. Masonry Specialist & Founder, GO Masonry LLC. Depending upon the requirement of the preferred use of the slab and the loads coming upon the slab. A well-poured concrete slab with a deep, sturdy foundation can last for 30 to 40 years. Include your email address to get a message when this question is answered. You can always cut out old concrete and replace it. Another way to achieve great cleanliness is ", "It helps me to supervise my job at home.". It sounds like the existing porch had an unstable footing for the soil movement (freeze/thaw) and/or was attached to a home with a lot of movement. The wet mix is there to help the new concrete bond to the old concrete, so you don’t need a lot of it. Put your excess concrete in a contractor grade trash bag and then dispose of it. Then, if you want to patch the concrete, apply a thin layer of cement paint, pour a well-mixed concrete patch into the holes, and wipe the surface with a wooden float. The aggregate in a concrete mix is listed on the label. As trees mature, their root systems naturally spread out. This helped great, let me know that I did the right thing. If new concrete binds to the existing slab, cracks are inevitable. Then, build a perimeter, or a wood brace, that is the same height as you want the concrete to be. If you are using a concrete patching product, you most likely do not need the adhesive. cleaners meant for concrete use, one needs to scrub spot that proves difficult If you're done using your tools, clean everything off with water and a wire brush. The condition of the existing slab is the primary factor that determines how long the new concrete will last. Concrete is marvelous stuff but in time it will deteriorate. Gerber has over four years of experience running GO Masonry and over ten years of general masonry work experience. This can work well when priming small areas. While pavers, stones and other types of paving materials offer a more decorative look, concrete is valued for its strength and low maintenance. It didn't quite come out the way, "Thank you for showing how to add concrete on top of concrete. The cement acts like an anchor for the wood post, so that it is not easily pulled up. Video Transcript: Hi. Most home improvement stores sell these cleaners. Can a concrete slab be poured over an existing 6-inch, heavily cracked concrete porch? How can I remove/excavate existing concrete? ", "We can now know anything that related with concrete. 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