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OK, so I’ve got this narrow (< ¼”) crack across the whole width in the concrete where my front steps meet my front sidewalk that I would like to fix. It’s probably from some differential settling between the foundation and the sidewalk, and I don’t want to make a major — either time or materials — project out of this if I can help it. Quikrete® makes two products — and the local HD conveniently carries both — which look like they could work. The Concrete Crack Seal is a latex emulsion for “repairing cracks in sidewalks, patios, and driveways” while the Concrete Repair is a sanded acrylic formula for “filling and sealing cracks in concrete” in “vertical or horizontal applications.” Prices for the two products in 5.5 oz tubes pictured above are within a dollar of each other, with the Concrete Repair going for around $3.50 and the Concrete Crack Seal about $2.50, so cost is not a major issue for this approach.

Any of you Toolmongers have experience with either one of these? Are there other options or alternatives — besides buying a Bosch jackhammer and having a few cubic yards of concrete delivered?

Concrete Crack Seal [Manufacturer’s Site]
Concrete Repair [Manufacturer’s Site]

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11 Responses to Quikrete Concrete Fix: Repair Or Seal?

  1. Pepster says:

    I haven’t used either, but it looks like the latex (crack seal) product is not meant to provide any sort of structural strength, only prevent further degradation or weed entry. Meanwhile the acrylic (repair) is more of a concrete patch meant to strengthen, fill, and prevent further cracking.

    I would ask this: Is the crack affecting the structural integrity of the concrete? For a flat surface like a sidewalk, no. For a basement wall or exterior steps, yes.

    You can then decide if you need to:
    “Seal” superficial cracks in a sidewalk that might get worse if ice/grass is allowed in.
    “Repair” cracks in structural concrete that might worsen or lead to failure.

  2. Old Coot says:

    No experience with either but I can rave about a product from Liquid Nails called Concrete and Mortar Repair. Comes in tubes that fit caulking guns. It’s grayish in color, remains flexible (but not soft) and I’ve used it in long cracks up to 3/8″ wide in some poorly installed sidewalks that I’ll someday have to remove due to poor soil stability underneath. Some of these repairs are over two years old and even with additional movement of the concrete, the cracks have remained sealed.

  3. I’d go with the seal. If it’s from settling, it’s going to continue to slowly settle, so you might as well fill it with something a little flexible.

    My house is concrete block on a lot raised above grade with concrete steps leading to it and concrete sidewalk in front. I patch a lot of concrete and always just use their vinyl patch compound, though the stuff I have is their dry mix that comes in a bucket and is cement+vinyl. Used it to repair big 4″ chunks missing from the leading edge of some concrete steps 2 years ago and it’s holding up great. Used it on my chimney to repair _big_ holes in the side. The stuff really is super durable and resists our Michigan winters. Mixed fairly dry you can fill fist sized holes on vertical surfaces or even on the bottom of overhangs without it running out. It even seems to stick to painted surfaces pretty well. Were it me, I’d open the cracks up a little with a rock hammer and fill it up.

    Man, I love patching concrete.

  4. Older than Dirt says:

    The crack repair works great. I used it where the porch meets the house and works great. Also used it on the back steps and patch is still there.

  5. Alex M. says:

    Here’s a related question – I have some joints in between (for example) my driveway and my garage slab that were originally “filled” with what looks to be 0.5″x1.5″ wooden boards. These have deteriorated and I don’t know if I want those rather large joints filling up with crap. Is something like this, a durable semi-elastic filler, suitable for filling those joints? Anyone seen wood-filled joints like this before?

  6. rob says:

    I have seen polyurethane expansion joint compound used in parkades
    where the slab was pored with foam in place and dug out then filled with polyurethane I just found a tube of it

    sonolastic NP 1
    gun grade polyurethane sealant

    it is used for all sorts of stuff sealing around windows as well
    there may how ever be specialized blends of it for various things
    comes in caulking gun tubes or sausage gun type tubes

    the wood filled joints are expansion joints

  7. Gordon DeWitte says:

    DHC Supplies carries the Sonolastic NP1 (http://www.dhcsupplies.com/store/p/2-Sonolastic-NP1-Sealant.html). They also have Sikaflex-1A which can be used with Nomaco Sof Rod backer for deep gaps, but I believe the Sika product is more for masonary wall gaps.

  8. bob says:

    Pepster and Patrick make good points.

    Most products above work well as described. Or, buy some fast setting concrete like “Rapid Set” at HD (available in small boxes too). Use latex adhesive or just plain old elmers. If a hairline crack develops on the edges, use one of the latex based products above.

    Do not use quickrete or other fence post fast-setting concretes.

    Nick scrape that wood out, use what rob suggests (expensive) and use something like this:


    or caulk it with something similar to sikflex’s products line. None cheap.

  9. Mike says:

    Seal lasts 3 or 4 years and then has to be redone… no good for cracks more than 1/8″

  10. Mark Lewis says:

    One idea: if you need to fill underneath, Quikcrete makes a sand filler for setting patio pavers that is “polymerized” so that, after it is swept in, you can wet it and the sand bonds to itself so as to resist falling out from between the pavers. If I had a ground level crack that had space to fill, I might be tempted to try adding this to the crack up to a reasonable level, then topping off with a sealer. I used this stuff on my patio and think it is worth additional experimentation. Not expensive either, considering the quantity that you get from one bag, vis a vis gaps and cracks in concrete, ie: plenty for you and several neighbors to fill all your cracks and gaps and still have backup.

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