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How to Repair Cracked Concrete

How to Repair Cracked Concrete

by Ethan Hagan (email Ethan) | | November 8, 2012 | 43 Comments »

Ever since Jocie and I purchased our home in 2006 the concrete stoop has had this long, ugly crack, and this past summer some yellow-jackets tried to take up residence within the crack. That was enough for me to bump the concrete repair to the front of my to-do list.

If you look around online, the typical repair involves filling the crack with a flexible patching compound followed by a sealant. The result is a structurally sound and visibly unattractive repair. I wanted something better because this is a repair that everyone will see when they come to our front door.

Tools & Materials

Quikrete generously sent me a bucket of FastSet Repair Mortar which is used for repairing concrete, masonry and stucco. The mortar is polymer modified, rapid setting and features a “low-sag formula” which makes it ideal for vertical and overhead repairs.

It’s important to know that this crack has not moved or expanded at all for the past 6 years. If there was any chance of movement, the appropriate product for this repair would be a flexible, polyurethane concrete crack sealant.

Fortunately temperatures here in Maryland are still above 32° F even at night. Otherwise the water (mixed with the dry mortar) would freeze and cause the repair to crack. If the temperatures are too low, pros often use accelerant to speed up concrete set time and insulating blankets to trap heat. During the hot summer months, pros use retarder to slow the set time.

I don’t own any concrete tools. Instead, I used an old drywall knife and a grout float. I also grabbed a wire bristle brush and hammer.

Step 1: Clean Crack

I started this repair by cleaning the crack with my wire brush and removing any small, broken pieces. I used a broom to clear away any leftover debris.

Step 2: Mix Repair Mortar

I combined a portion of the 20 lb. bucket with warm water (speed up set time) until it was thoroughly mixed and a stiff, gel-like consistency.

Step 3: Apply Mortar

Before starting, I sprinkled some water over the concrete to wet the surface. Using my drywall knife I applied mortar to the crack and skim coated the rest of the face of the concrete. Much like painting, it’s easier to spot a partially repainted wall so I used the corners as transitions.

Step 4: Tool Mortar

I continued tooling the mortar after the initial set to achieve a smooth uniform look.

As the mortar hardened, I switched to my grout float because I could apply heavy pressure and better round the corners.

Step 5: Pulverize Old Concrete and Use on Transitions

I used a hammer to pulverize a few chunks of concrete into a fine powder, and I lightly dusted the top edge where the repair meets existing concrete. My goal was to further hide the transition from new to old.

Step 6: Allow to Cure

Aside from ensuring the repair doesn’t dry too quickly during the first 24 hours, there are no special procedures to cure FastSet Repair Mortar.


Even with the warm water, the cooler temperatures slowed cure time. After 24 hours the mortar color was much lighter and it began to blend with the existing concrete. I used the wire brush again to smooth out a few places along the corner.

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Conversation on This Article

43 Responses to How to Repair Cracked Concrete

  • Brady responds...
    November 8th, 2012 8:24 am

    The detail steps (dusting with concrete powder and wire brushing) make this look like a pro quality repair! Great work.


    Ethan Reply:

    Thanks Brady. I got the idea for the concrete powder from thinking about how to re-point some brick. It’s next to impossible to match existing brick mortar from 20+ years ago. I haven’t actually tried it yet, but it worked well enough on the concrete.


    Skeeter Reply:

    That’s not a repair. Thats a cover up. And soon the same crack will appear. Guaranteed!!!


    Pat Weigand Reply:

    Skeeter if this is not the proper way to repair then how should it be repaired? I have a small crack that I want to fix and this looked okay to me but I really don’t know how to go about doing this. Would you post how to properly repair a concrete crack? Thanks!

  • jeff_williams responds...
    November 8th, 2012 9:32 am

    Color me surprised. I thought it would turn out like lipstick on a pig but it looks really nice. After a little weathering no one will ever know.


    Ethan Reply:

    HA! Thanks Jeff. It’s a small porch and now that I’m finished, I’m debating giving the rest of it a quick skim coat to make it look really uniform.


  • Icarus responds...
    November 8th, 2012 10:08 am

    How about that. you ignored this for 6 years and it took less than 60 minutes (+ 24 dry time) to resolve, right?


  • paintergal responds...
    November 8th, 2012 10:18 am

    That is a much nicer fix than the one we attempted. Definitely need to check this out.


  • frazzled5 responds...
    November 8th, 2012 10:42 am

    Ethan, Why dont you all live in Georgia? We could use your expertise in fixing the concrete on the bottom portion of our cedar sided home:)


  • Reuben responds...
    November 8th, 2012 10:47 am

    Pretty good fix. I’m also impressed with how well it turned out. The pulverized powdering is a good trick.


  • poiboybf responds...
    November 8th, 2012 1:01 pm

    Turned out great! Looks so much better now than the first picture.


  • WH responds...
    November 8th, 2012 2:20 pm

    Made it look easy. Better than 1 of my own recent efforts ;-)


  • Jake responds...
    November 8th, 2012 4:31 pm

    Looks great. Love the blending Techniques.


  • bigredmachine responds...
    November 8th, 2012 9:55 pm

    I have seen the quick fixes at big box stores that don’t work, good to see you address this issue


  • John responds...
    November 9th, 2012 11:23 am

    Great job. I needed this one!


  • trebor responds...
    November 11th, 2012 9:26 am

    Outcome looks great! I like the attention to detail on transitions. I wonder why the crack appeared but hasn’t expanded at all though…seems like the crack could still be suspect to expand


  • Handyman Hawaii responds...
    November 30th, 2012 6:05 pm

    I also use these methods when repairing concrete structures in buildings and homes with old looks: cement is very hard to work with if you zero experience…..


  • ranch-burger responds...
    December 3rd, 2012 12:57 pm

    I recently pulled up the carpet in 3 of our bedrooms and found what appear to be surface cracks on the foundation – should I fill/repair these before the new flooring goes down?


    Ethan Reply:

    Hi Ranch-Burger,

    I depends on the new flooring, and the extent of the cracks. For instance, minimal cracks can easily just be covered up with new carpet / carpet pad. For tile, you may want to consider sealing it with crack-isolation membrane. I know this isn’t a definitive answer, but I hope it helps.

    Let us know what you end up doing.


    jeff_williams Reply:

    Depending on your area of the country Radon may also be a concern with those cracks. If you have the floor torn up it would be a good time to test for it and if it’s high, install mitigation measures.


  • supimeister responds...
    December 14th, 2012 11:51 am

    nice tricks! super helpful


  • HANDYMAN51 responds...
    May 16th, 2013 1:03 pm

    Bookmarked and on my ” do soon” bucket list. O.K., I live a simple life! Thanks for making it even simpler.


  • EvaS responds...
    July 13th, 2013 12:50 pm

    This is great. Do you have any tips on setting concrete in 80 degree temperature? I want to make sure it won’t crack.


    ConcreteJoe Reply:

    Hey Eva

    My experience with heat and cement cracking is wait til it has set and is finished tooling and mist with a garden hose to keep the concrete from setting to fast. As concrete sets the chemical reaction makes it get hot so I usually mist concrete after the entire job is broom or wood float finished. Be careful not to spray to hard just a fine mist should do the trick hope this helps.


  • HANDYMAN51 responds...
    July 27th, 2013 9:02 pm

    Had some concrete problems on our front steps, some areas crumbling on step’s edges and a major horizontal crack on a horizontal surface. I cleaned the areas, applied a coat of a liquid bonding agent, placed some compressed ” chicken wire” in the large horizontal crack, then placed a 2×10 piece( wood surface brushed with motor oil to allow easier removal) flush against the step with the crumbling edges. The 2×10 was held in place with some concrete blocks. I filled the broken areas on the step’s edge and allowed the concrete repair to set up. I then packed the horizontal crack and placed the board against it, held in place by the blocks. I was pleased at the results, though I must admit my repair was done as aesthetically as Ethan’s!


  • How to Repair Cracked Concrete - Craft Like This responds...
    November 26th, 2013 4:29 pm

    […] How to Repair Cracked Concrete […]

  • How To Revive Old Concrete With Decorative Leaves - responds...
    September 25th, 2014 6:41 pm

    […] This post shares tips and tricks on resourceful ways to repair cracked concrete. With everything you will need to get going including materials and step by step instructions. Soon you’ll be repairing the concrete cracks in no time! Details at: Repairing Concrete Cracks […]

  • Jason Roland responds...
    March 13th, 2015 11:45 am

    You did a great job sealing that gap and it looks much like the older concrete and blends well. It is hard to tell from your photos but another option is to have the concrete lifted so it is even again and flush on the front. If you do have it lifted, using a company that uses polyurethane foam is the way to go!


  • Tim responds...
    April 3rd, 2015 8:35 pm

    That is one heck of a bandaid. Sorry but this is not a repair, a repair would be mud jacking. Cracking concrete is a sign of soil compaction or voids forming under a slab. Simply smearing concrete over a crack is not a fix. You’ll be doing this over and over again for the duration.


  • Don responds...
    April 7th, 2015 9:14 am

    Tim could you explain “mud jacking” and how it is accomplished? Is this something that the “average” homeowner can do on their own?


  • sue responds...
    April 7th, 2015 6:17 pm

    Mud jacking is a system that uses expanding foam or concrete. The company will come assess if it is needed. The drill holes at cetain areas and literally pump in foam or concrete depending on your choice of company. It is done slowly and meticulously as over filling can lift too high or damage pipes underground. Not recommended to try yourself….


  • Delores Lyon responds...
    April 23rd, 2015 6:16 pm

    Thanks for sharing this advice on repairing concrete in your home! I have a couple of cracked steps outside my front house as well, and I’d like to get them fixed before we put the house up for sale. Hopefully this method will help me make good repairs, but I’ll be calling a professional if it doesn’t look good enough.


  • Joy responds...
    May 4th, 2015 11:38 pm

    I have a drain chanel on my concrete patio slab & crack has developed in this chanel…would I use same repair process & product you used?


  • chris responds...
    June 7th, 2015 2:48 pm

    That’s not repairing that’s covering up the issue. The “fix” will pop off in a year and it will look like the way it does before the “fix” The proper way to fix the issue is bust out the concrete re-pour the step


    Al Reply:

    the ultimate fix is your way, truly…. but for those who can’t afford to get concrete (and believe me, there are quite a few of us who literal can’t afford a bag or two, the mixing equipment….) This will work….and as long as the concrete is stable, it will hold for longer than your estimate….maybe not much longer…but longer. and you have to admit that it looks good which is what he wanted.


  • Jason Roland responds...
    June 29th, 2015 1:45 pm

    This is great advice! Thanks for the step by step process. Being in the concrete lifting business, I highly recommend using a company that uses polyurethane foam – for larger projects than this. It won’t shrink or expand like mud will so you won’t have the same problem in the future.


  • peter mckechnie responds...
    October 13th, 2015 5:48 pm

    I have similar cracks in my driveway, and have been pondering over this issue for a while…thanks for this advice of quickcrete. Can you paint over this product succesfully? this is my next step


  • 15 Effortless Ways To Add Value To Your Home responds...
    February 15th, 2016 8:50 am

    […] Repairing Cracked Concrete […]

  • […] Repairing Cracked Concrete […]

  • Dale Langanke responds...
    May 27th, 2016 7:23 pm

    I have a couple hairline cracks in the concrete on my back porch that allow water to leak into the fruit celer below. How can I steal them without making the porch look bad ? I have considered painting with a sealer but have never seen a paint that held up without peeling in time. Also if chairs or patio table move on it, paint scratches off.
    Any suggestions ?


  • Marty Masker responds...
    July 17th, 2016 8:52 am

    How about “How to repair cracks in a stone chimney and hearth (inside and out)”!


  • Josie responds...
    September 10th, 2016 1:09 am

    Great job in the repair. Looks awesome. A coat or two of concrete stain and sealer would look great. Thanks for the tips for us ” regular folks” !


  • Eddie responds...
    October 26th, 2016 8:38 am

    Could this method be used to fix cracked sidewalks or curbs,


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