Get Our Bathroom Remodeling GuideLearn More
Get Our Bathroom Remodeling Guide

blog

Repairing Cracks in Concrete

7 Minutes is All You Need

As Seen On
by Jeff Patterson in Exterior DIY Projects

This time of year I start to notice all the flaws in my driveway, steps, and walkways.

While doing a routine fall preventive maintenance check at one of our rental houses I noticed a sizable gap on the walkway between a concrete step and landing area.

The gap was about 1/2 inch wide and seemed to be getting bigger over time. Although this could just be my bad eyesight (anyone else feel my pain here!).

I’d like to avoid the possibility of the crack getting larger and creating additional fractures.

My goals for this quick project were to fill the large crack,make it watertight, and allow it to expand/contract with the natural freeze & thaw cycles.

These are the supplies you’ll need

The total cost of this project if you have to buy everything is $23.15.

I’m going out on a limb and assuming most of you own a broom and concrete crack filler (LOL, just kidding). If you own a broom and scissors the total cost is $11.20.

If your crack is less than 1/4 inch then you don’t even need the foam tubing.

Filling and repairing cracks in concrete is super important to prevent further damage. This is an easy fix and I walk you through it via a video as well as a step-by-step guide.

So let’s get started because today you’re going to discover a new cost saving home repair fix 

Clean the Crack-Step 1

Use a broom or brush to clean the crack. By the way, the brush I’m using in this video was my grandpa’s. Before he passed away he had the presence of mind to give away all of his material possessions except for few tools.

I kept his brush and a few mason trowels as a reminder that you can build anything if you’re willing to learn and be persistent.

If you’re concrete crack has grease on it visit your local hardware or auto parts store and ask them for a product that will help remove the residue.

Clean the crack when repairing concrete

The crack I was working with was the result of the step and landing area pulling away from each other. It was a control joint that was purposely put in place to prevent cracks from occurring.

This control joint unfortunately became “out of control” and widened too much over the last 60 years. If water continues to get into the huge crack it will continue to separate the step and landing area from each other.

And the type of repair that this process will lead to can be very expensive to fix.

 

Insert Foam Tubing (aka Polyfoam Caulk Saver) into Large Cracks-Step 2

The crack I had to repair was about 1/2 inch wide.

Although Sakrete crack filler can be used for cracks up to this size it’s best to fill in large gaps with the foam tubing.

The foam tubing should be slightly wider than the crack to create a tight fit. I used a 5/8 inch wide variety.

Add foam tubing to large concrete cracks

Place the tubing in the crack and push it down. There should be a 1/4 inch space between the top of the foam tubing and the top of the concrete crack.

This 1/4 inch space is where the concrete crack filler will be poured.

Click on this link for more details on the polyfoam caulk saver.

It’s made by Frost King who also has a ton of other great weatherizing products.

Check out their website (www.frostking.com) because you’ll get a lot of great ideas of how to keep the cold weather from increasing your heating bill.

 

Apply Concrete Crack Filler-Step 3 

This is the fun part. Do you remember doing those crazy art projects in grade school?

This is the adult version AND it saves you money in the long run.

Shake the concrete crack sealer vigorously for about 15 to 30 seconds.

Apply a 1/4 inch deep layer of concrete crack filler to the concrete crack

Cut the applicator tip with your scissors (or a utility knife or a steak knife-unless you’re vegetarian).

Squeeze the bottle and allow the crack filler to seal the crack where the foam tubing resides.

Allow the filler to setup for 24 hours before walking or driving on it. I checked my crack filler (this phrase would have gotten me a demerit in Catholic school and certainly I’d have detention by the end of this tutorial) after 30 minutes and it wasn’t tacky.

Click on this link for more information on the Sakrete crack filler I used.

If your crack is super deep (DEMERIT!) you can add a second application. A 24 hour wait time is needed between each successive application.

I didn’t trowel or smooth out the Sakrete concrete crack filler. You’ll find that it is self leveling and will look fine after it settles.

Here’s a video of this repair project. You should watch it because it walks you through the entire process.

 

What’s Next

Our tutorial showing how to repair concrete expansion joints also comes in handy – and will save you a ton of money.

Also, grab our free guide if you’re doing a DIY bathroom remodel – it shares how to remodel a bathroom in 10 days or less

Send Me The Guide

 

Cheers,

Jeff Patterson

 

 

48 Comments
  1. SheilaG @ Plum Doodles says:

    Another great tip, Jeff! We recently had to have our driveway jacked- they filled the cracks when finished, but don’t know if they used caulk saver. So, yes, we know about those expensive driveway repairs! :

    1. Jeff says:

      Thanks Sheila, sorry to hear about your driveway. Anything expensive is always a bummer. I hope your weekend went well-judging by your Facebook pictures it did!

  2. Great info on cement crack repair. My problem is my crack is not in level cement so when using Self-Leveling caulk it all flows down hill. Is there another, better product for this issue?

    1. Hey Rob,

      I have a similar issue since our driveway is on a hill. You could try SikaFlex Concrete Fix or SikaFlex Mortar Fix. But call Sika first and ask what they recommend for your specific project. They are really cool and will totally help you out. Here is their number 800-933-SIKA

      Here’s the description of the Concrete Fix from the Sika site

      Sikaflex® Concrete Fix
      Moisture-cured, 1-component, polyurethane-based, non-sag elastomeric sealant. Meets Federal specification TT-S-00230C, Type II. Meets ASTM C-920, Type S, Grade NS.

      Close Details
      Use
      Designed for all types of joints and cracks where maximum depth of sealant will not exceed ½ in.
      Suitable for vertical and horizontal joints; readily placeable at 40°F (4°C).
      Has many applications as an elastic sealant between materials with dissimilar coefficients of expansion.
      Ideal for:

      Weatherproofing of joints,cracks and gaps in concrete, brickwork, blockwork, masonry, stucco and metal frames.
      Joints in walls, floors, balconies, around window or door frames.
      Expansion joints.
      Roofing.
      Characteristics and Advantages
      High elasticity – cures to a tough, durable, flexible consistency with exceptional cut and tear-resistance.
      Stress relaxation.
      Excellent adhesion – bonds to most construction materials without a primer.
      Excellent resistance to aging, weathering.
      Non-staining.
      Urethane-based; suggested by EPA for radon reduction.
      Paintable with water-, oil- and rubber-based paints.
      Capable of ±25% joint movement.
      Color

  3. Betsy Bekken says:

    Will this repair technique also work on a vertical concrete block wall where one section was added later and has settled creating a crack about 1/2 inch wide?

    1. Hi Betsy,

      You’re better off using a different product. Something akin to a mortar repair that will accommodate the gap in question. Or just use mortar.

      Jeff

      1. Betsy Bekken says:

        Thank you

  4. Bella McNally says:

    What would you recommend for really fine cracks in cement? Or for loose pieces of cement between tiles framing a pool?

    1. I recommend using concrete crack sealer Bella from Quikrete. You can find it at all home stores. And it’s not expensive, like $3-$5.

      Plus no special tools are needed.

      For your loose pieces of cement you can use a fortified patching compound. Quikrete has one called Concrete Patching Compound. It’s meant for fixes no more than 1/4 inch deep.

      I hope this helps. Let me know what you think 🙂

      1. Katthy says:

        Hey Jeff can you tell me the best way to fill in a fine crack in an inside floor that I want to stain?

        1. Is the inside floor made of wood or concrete Kathy? If it’s wood you can use a number of crack fillers that are stainable but I’d test the filler on a scrap piece of wood with the stain and see how it turns out.

          You could do the same thing with a concrete crack filler, i.e. test it on an inconspicuous area that you apply the crack filler to and see how it looks once it dries.

  5. Onnie Eddleman says:

    About your grandpa’s brush. I have one just like it. I’m 82 yrs. It was given to me to clean rails on spinning frames in Woodside Cotton Mill in 19 48. Would n’t want to use for that kind of work .It is made of horse hair and is an antique. You might want keep it as is.

    1. Thanks Onnie. I bet the brush you have is identical to my grandfather’s. He would have been 34 years old in 1948.

      He also had a few cement tools that I’ve used. It’s so neat that tools and brushes back then were made so well. And that I can use them two generations later.

  6. Sophia says:

    hi
    that is a great tip if the crack is nice and straight as u have it ..what about if the crack is veiny and uneven ….no real space to slip in the tubbing ….??
    thanks
    Sophia

    1. Good question Sophia.

      How big is the crack in your concrete? If it’s small you don’t need the backer rod.

      If the crack is large and just awkward like you described you can cut the foam backer rod to fit the spaces.

      It’s fine to cut the backer rod because you’re only using it to conserve on the crack filling product.

      Hope this helps but please let me know if you have any questions.

  7. Rob Looper says:

    For deep wide cracks you can also use sand to help fill them before applying the crack filler so you don’t have to use as much. I am sure it is less expensive than the foam filler, sometimes where you would purchase the sand they have broken bags and will make you a deal on them or they have spilled and will give it to you if you don’t need too much.

    1. Good idea Rob, thanks for your suggestion. It doesn’t hurt to ask if the store will give you a discount on the broken bag. I bet they will 🙂

  8. Connie says:

    Would the concrete crack filler work on a long, but narrow crack in a limestone step?

    1. I haven’t used it for that kinda repair Connie but it might work. Give the folks at Quikrete or Sakrete a call ask them what they think. They probably have a great opinion on this.

  9. kimberly says:

    How does this hold up as the weather changes? We get to below zero temps in the winter in the Midwest. Does this expand and contract with the temps or is it solid? Also, does this aid in weed prevention in the cracks? Thanks!

    1. Good questions Kim. I’m in pittsburgh and we get a lot crazy weather, too.

      If you have a gap that needs expansion and contraction give SIKA’s self-leveling sealant a shot. Use it along with a foam backer rod and you should be good to go.

      Just be careful with the self-leveling sealant though, it will run and is super fluid. So if you have a slope you’ll want to figure out a way to prevent the product from running into any area you don’t want it.

  10. Pam Ross says:

    Jeff, we have some concrete tables around our pool that have a terrazzo – type top. Little pebbles pressed into the concrete. Over the years these pebbles have come out and left large areas empty. Last year I tried filling these areas with a concrete patching compound but it dried very rough. Do you have any ideas about how to fix these table tops so they are smoother. They are really scratchy are don’t look too good either.

    1. Your tables sound like they looked super cool back in the day.

      Did you try a vinyl concrete patch? This kind of can accommodate a feathered edge of 1/16 of an inch.

  11. Angela Pierce says:

    We have a sloped driveway and long with long cracks. Just powerwashed it and now noticed holes created by the powerwash. can the Bella from Quikrete be used for this. cracks not wide enough for tubing. do you have any idea a contractor might charge for repairs of this kind for a 30 ft driveway?

  12. Brenda says:

    What to use or how to fix a cement floor with small cracks and run downhill. should it be leveled. It is a living room floor.

  13. Katy says:

    Thanks for the tips. Is there any way to mudjack small areas yourself? I have a sloping step outside my front door. Thank you!

    Katy

  14. Tara says:

    I did my driveway crack just as you should with backer road and one thick bead of quickrete concrete repair filler and from the surface it looks great but it’s flexible after 24 hours and when pushed on wet compounds seeps up. The surface is dry but underneath still wet; will this cure or do I need to clean out and start over? Thank you

  15. John says:

    Jeff,

    We filled the cracks with silicone filler of some sort for concrete repair and if sure
    did a great job filling the cracks in the driveway however it left white lines and grey ones
    on the driveway! How do I remove the lines so they don’t stand out so much on exposed
    aggregate. Thanks , John

    1. Julia says:

      Hi. We have a couple of hairline cracks in our bottom concrete deck. I’m thinking of using your recommendation for repairs. My question is will this dry the same color as the concrete we currently have or will it be obvious that a repair has been made? Thank you

  16. Sheila says:

    What is the best filler for the following Driveway Crack…
    An uneven vertical crack on an incline, and which is about 1″ deep and 1/4″ wide? Thank you.

  17. Steve says:

    Thanks for the tips. I am contemplating a DIY repair of a 45 year old slab, just to make it tolerable until the budget permits replacement. If nothing else, this might keep the weeds out of the cracks for a while.

  18. I have forced air heat/AC combination. The tubes from the basement unit to the outside condenser go through a concrete block wall. Whatever was used to seal the hole is gone and the gaps are so big, I can see through them. I want to seal it but also not damage the tubing or make it impossible to service.

    Both steel wool and concrete filler have been suggested.

    Your suggestions would be appreciated.

    1. You could use foam sealant. That way the lines could still be serviced and the foam would seal air leaks.

  19. TIMOTHY MCQUAID says:

    We like to call that Foam in the north-east backer rod

  20. Bob says:

    Some additional thoughts:
    Make the seal (with the sealant) half as thick as it is wide. You want the seal to adhere to both slabs and contract and expand as the slabs expand and contract, not be a plug that pulls loose from one slab when the slabs contract..
    The top of the seal should be recessed just a bit below the concrete surface. The seal is not really a load bearing or wear surface – it’s a seal.
    Sprinkle a little play sand over the seal while it is still wet to match it to the aged concrete.

  21. Salene says:

    Hi we just had our concrete driveway replaced 7months ago and already have a 3ft hairline crack in the part that wasn’t pinned to the house. The contractor says that they can’t seal or fix it. Would these products work to deal it so it doesn’t get worse? Thanks

  22. Nicole says:

    Would this technique work on the face of a step? We have a cracked step breaking away from the bottom 2 steps and the crack is horizontal but on the face of the step where it joins to the rest. Thank you

  23. Ashley says:

    Hello! So, we are looking to buy a home and fell in love… and of course the seller refuses to repair issues. There are big gaps (like at least an inch probably if not 2) between some of the slabs of the concrete walkway up to the home (on a hill). Would this help? We know we can get them moved/ jacked up professionally, but don’t think financially that will be in the cards after the purchase of the home.

  24. Sunny Alexander says:

    Hi! Thanks for your video, it was quite helpful. Here’s my situation: I have a patio slab with one crack that goes along the width (10 ft.) I have cleaned out the old repairs. There is one spot (about 8 inches long) that is deep i.e. down to the dirt below. The rest of the cracks are minimal and would work as your video suggests. Re: the deeper crack: Should I cut and layer backer rods or first fill with sand (or another material), then follow with backer rods and lastly the concrete filler? Any suggestion would be greatly appreciated.

  25. Cher Angelo says:

    Hi and thank u and everyone for the great instruction. .I have a painted concrete slab in the front halll doorway exiting from inside hall to outside porch. U step down from it onto porch thru door and stormdoor.. It’s in the doorway. Got a crack about its entire width frim.in yo out but it’s gotta be really deep. Tried liquid concrete in canister but even after successive tries it seeped down so far and still looks unrepaired. The stuff disappeared into crack. I’ve no money for pro repairs am elderky female handicapped looking for easiest possible fix. Can u recommend anythng? I can’t lift 40 lb bag of cement, hsve no one to do so.

  26. Toliver says:

    This was great! At first, I could not find the site that you referred to homerepairtooter.com but then realized it was spelled homerepairtudor.com.

    Toliver

  27. Toliver says:

    Make that homerepairtutor.com

  28. Ken Hwan says:

    I am very appreciate of the advice to clean the concrete crack very well before filling it in. My neighbor recently filled in a concrete crack on the steps leading up to his house and after he finished you can still see some leaves in the crack! I will be sure to follow your advice and clean the crack really well before filling it in!

  29. Michelle Phair says:

    Great post! I have a huge crack (DEMERIT!) to repair in my garage, I don’t dread fixing it now. Easy peasey! You made my day. Thanks so much!

  30. Cindy says:

    We filled a crack on cement porch however it is now not flush with the surface. How do we fix that?

    Cindy

  31. Frank Campos says:

    Hi Jeff, great article and will use the information to repair hairline cracks in my driveway. Quick question – I’m having a concrete patio poured that will butt up (DETENTION!) to the foundation for my house. I’m concerned about movement of the patio slab relative to the house foundation. Do you recommend using the backer rod and maybe a polyurethane caulk between them? Or do you have other recommendation. Thank you in advance.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.