Posted: 10/6/2009 10:27:37 AM EDT
Soooooo, I've been tasked to repair a walkway which has some fairly significant cracking and damage. A lot of it is missing or very, very chipped up. So my question is can you layer new concrete on top of old, or should I just be expecting to rip allllll of the old stuff up and pour on top of new sand/gravel? Anything else I should know about repairing concrete? Thanks guys. 
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You can "try" the concrete resurfacer made by Quikrete but more than likely it will fail.
Your best bet is to rip out the old stuff and pour new concrete. You can not pour new concrete over that old stuff. It will crack and fall apart in no time. Concrete work is never cheap. 
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Quoted:
You can "try" the concrete resurfacer made by Quikrete but more than likely it will fail. Your best bet is to rip out the old stuff and pour new concrete. You can not pour new concrete over that old stuff. It will crack and fall apart in no time. Concrete work is never cheap. What he said. |
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Quoted: Soooooo, I've been tasked to repair a walkway which has some fairly significant cracking and damage. A lot of it is missing or very, very chipped up. So my question is can you layer new concrete on top of old, or should I just be expecting to rip allllll of the old stuff up and pour on top of new sand/gravel? Anything else I should know about repairing concrete? Thanks guys. You really want to rip up and replace. |
| Depending on how much you want to add you can repair it. Dowel in rebar into the existing concrete, add some wire mesh for structural support and pour on top of the old concrete. This will not work if you are only intending to add just enough to cover the bad spots. You would need to add several inches. If you cannnot thicken the concrete - bust it out and replace it. |
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Depends on the failure mode. If the sub base has not failed (shifting slabs, pitching) AND you can get away with the walk being 3" higher, you can lay mesh over the old using chairs and pour. I would recommend a good acid clean of the existing concrete to remove all weathered biofilm (algae, lichen, fungus), then use a bonding agent before the pour. If removing the old, cut it into 2' lengths with a jackhammer, cutting the rebar/mesh with a saw. Then drag the pieces out, this is easier to clean up. It is hard work. BT, DT. |
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there are two types of concrete:
concrete that is cracked and concrete that is going to crack you need to rip up the old stuff and find out what caused the old crete to crack (tree roots 99.99% of the time). you would need to dig those out a good bit. then replace the concrete. Or you can relay the walkway with step stone and rocks. 
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