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How To Fix Hairline Cracks In Concrete Patio

Question: What Does Blk Mean When Marked On Concrete Flooring By A Crack

Carol said:New home construction – pulled up cracked tiles – large crack in concrete flooring with inspector markings of “blk” in two areas around crack. What does “blk” stand for?



“blk” is not a standard building inspection abbreviation that I’ve seen. Sorry I don’t know. Perhaps you could ask your local building inspector and let me know what she or he says.

Don’t just put down more tile without a better evaluation of the cause of the cracking and its impact.

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    Concrete Countertop Crack Repair

    Question:How do I fix a hairline crack in a concrete countertop, without the repair being noticeable? Also, what’s the best way to prevent these cracks from occurring?

    Need help with repairs?

    Answer:Hairline cracks can be challenging to repair. As the old adage goes, all concrete cracks. What’s important to a client is that those cracks are not visible nor do they impact the performance of the countertop. Well-made concrete countertops should not develop structural cracks. However, hairline cracks are possible, although not a sign of poor quality.

    Causes of Hariline Cracks

    Both hairline cracks and larger structural cracks are caused by stress relief. A crack forms when tensile stress builds up in the concrete and exceeds the material’s capacity to resist those stresses. Most large structural cracks in countertops form because of flexing, either because a faucet was tightened too much or the house settled.

    Repair Options

    A repair in a hairline crack involves filling the crack with a material that will bond to the concrete, restore the appearance of the countertop and prevent the penetration of liquids that could stain the concrete. In addition, the ideal repair material is more flexible and as strong or stronger than the concrete, so that future cracking is prevented.

    If you’re worried about the repairs being noticeable, consider .

    Commercial crack filler.

    How To Apply Concrete Crack Filler

    First, clean the crack area and thoroughly remove the dirt inside it. Next, get the concrete crack filler and shake it to mix all the ingredients well. Open the top of the nozzle with scissors. Then, place the tip of the nozzle into the crack and gently squeeze the product while slowly moving it along the crack area until you fill it in thoroughly. Lastly, allow it to dry.

    Insert Foam Tubing Into Large Cracks

    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.

    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.

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

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


    Filling Long Cracks In Concrete Paths Hard Standings Slabs And Drives

    How to fix hairline cracks in concrete driveway ...

    The last of the repair mortars we use is called Flowfast pourable repair concrete and it simply does what it says on the tin!

    It is mixed in the same way as both of the mortars above but the quantities that come in the tub allow for a wet, smooth flowing mixture. Watching the video in the Flowfast product review will show you exactly how to use this pourable concrete and how it can be used to repair concrete cracks very quickly.

    Mixing epoxy pourable concrete to repair paths

    Avoiding A Dusty Mess When Removing Release Powder


    Cleaning release powder from concrete surfaces after stamping is always a dusty and dirty mess. How can this be avoided?


    During one of my seminars on troubleshooting decorative concrete at the World of Concrete in Las Vegas, an audience member shared the following trick for removing release powder without the mess. I was so intrigued by the method he shared that I tried it, and can report that it works great! I never caught the gentleman’s name, so I can’t give him the proper credit for such a creative and helpful hint. Whoever you are, thanks!

    Take any fine-grade silica sand, and mix with water to create a heavy, stiff paste. Apply this paste randomly to the stamped surface. Then with a stiff broom or walk-behind scrubber, scrub the surface with the sand paste. The wet sand grabs the release powder, eliminating any dust, and also acts as a grit to help scrub the surface while removing the release powder. Depending on the color and amount of release on the surface, the process may need to be repeated several times to achieve the desired look. When I tried this method, one pass was all that was necessary to obtain a clean stamped surface. The sand containing the release powder can easily be washed off with a hose or power washer or left to dry and vacuumed up with a wet/dry vac.

    Does Homeowners Insurance Cover A Cracked Driveway

    Most homeowner’s policies consider an attached driveway part of the house and will likely extend the same coverage. If the cracking was caused by an accident or event that you will be filing an insurance claim for, then be sure to ask your agent about covering the driveway repair as well. This typically doesn’t include cracks caused by normal concrete curing and earth shifting, but it’s always worth asking about more severe cracks that could be potentially hazardous.

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    What Can I Use To Fill Cracks In Concrete

    Lawn & GardenLoz James

    Cracks in concrete patios, driveways and pathways can be unsightly – and will also become larger and attract weeds if left untreated. So what can you use to fill concrete cracks and how do you go about it?

    To fill narrow cracks in concrete that are ? of an inch wide or less, use an epoxy compound or a latex-based formulation to seal each crack. For larger cracks or chipped concrete edges, mortar mixes are the best option as they both fill and seal the cracks.

    Let’s dive down into the subject of filling concrete cracks in more detail, and discover some different products you can use to get the job done, plus a process to follow to get it done right…

    Table of Contents

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    Unsightly cracks in concrete not only detract from the look of a garage or patio, they can also lead to further problems as moisture seeps into the concrete.

    Luckily, there’s an easy way you can repair a cracked concrete slab or wall and prevent further damage down the track.

    Sikadur Concrete Fix is a two part epoxy adhesive and filler that can be used as a bonding bridge adhesive paste for concrete and most building materials.

    It’s simple and easy to apply and can be used for repairing cracks, holes and voids in concrete floors and walls.

    It also works as a structural adhesive for a range of materials including stone, ceramics, fibre cement, masonry, metal and timber.

    To repair cracks in a concrete floor, first ensure that the area is free from dust, grease and surface contaminants.

    Concrete fix can be applied to both dry and damp surfaces, but standing water in any voids, pits or pores should be removed prior to application.

    While wearing safety glasses and chemical resistant gloves, pre-mix both parts separately, then mix equal parts of each together in a suitable container. Mix thoroughly for three minutes with an electric drill and paddle mixer.

    Use a trowel to apply concrete fix to the prepared substrate and smooth it into the crack or to form the desired shape.

    Apply Sika Concrete Fix to corners using a shaped trowel

    The paste cures rock-hard, so make sure you clean all tools and surfaces using Sika Colma Cleaner before it hardens.

    Eliminating Ridges In Stamped Concrete Seams


    When we are stamping, we sometimes end up with a lot of crusting that we try to roll out or hammer away the next day. Do you have any tricks or suggestions for dealing with this type of problem?


    I assume you are talking about the material that pushes up between stamp imprints. If so, this is usually referred to as “squeeze.” You will always have some squeeze, but it should not be overwhelming. If you are getting too much, here are a few things to look at:

    Is the surface too wet? A wet surface can create more squeeze. Wait until the surface is a bit stiffer.

    Are you using imprinting tools with lots of edges and angles? Tools with multiple edges tend to create more squeeze because it’s harder to hold multiple edges tight during stamping vs. one or two edges.

    How old are your tools, and do the edges fit together tightly? Not all tools are built the same way, and if the edges don’t come together tight, you will get more material pushing up between them.

    To get rid of squeeze, the easiest method is to roll it out with a touch-up wheel or chisel while the concrete is still green. If you wait and come back after the concrete is hard, you can remove the squeeze with a good set of straight-edge metal chisels. The problem with waiting until the next day is that the areas exposed after breaking off the hardened material are now usually a different color and will need to be touched up with a tint, stain or colored sealer.

    What Do I Do To Camouflage Hairline Cracks On My Concrete Porch

  • on May 23, 2017This is not normal. Looks like stress crack from the corner. If there is a warranty get him back to fix it. You can try to fix it but they may get worse.
  • Naomie Moore aka baileyanddaisey, Castaic CA on May 23, 2017It is normal, nothing to be concerned about. I let those be as filling in sometimes brings attention to the minor surface cracks. Then you will be even more unhappy. If it really bothers you, you can always tile over the porch.
  • on May 23, 2017Go to Ikea and get some Runnen floor decking. They are wood tiles with plastic underneath so they easily snap together. Put those on top of your concrete porch. They are SOOOO stylish looking. You will really love the final results! Here is a link to them:
  • Rachel Brown on May 25, 2017It is normal. You cannot put a warranty on concrete. There is too many things that can affect the finishing of the concrete, weather conditions, the dryness/wetness of material when it was poured, ground movement or erosion and many other things. You can look into staining the concrete which will hide the cracks.
  • Step 5: Spread Sealer Along The Crack

    hairline cracks

    Next, mix up a slightly larger batch of epoxy sealer and apply it to the entire crack using a 1 ½-in.-wide putty knife or margin trowel. Spread the sealer about 1/8 in. thick and 1 in. on either side of the crack. Also, cover the entire flange of each injection port with crack sealer, leaving only the extended neck portion showing. Smooth out the sealer and feather its edges with a paintbrush dipped in mineral spirits.

    Adding Color To A Liquid Release


    Can I tint a clear liquid release agent to add color when stamping concrete? If so, how is it done?


    You will be hard pressed to find any official written guidelines on tinting a liquid release, but that doesn’t mean it can’t be done. Most manufacturers of liquid release don’t publish any guidelines because the process is more art than science, and each job will present different conditions and color requirements. Achieving success requires practice, experience, and some experimentation.

    The most common tinting method is to add a colored release powder to the liquid release and then shake the mixture well to disperse the color. Although many applicators have had success with this method, it takes practice to know just the right amount of tinted release to apply to prevent the stamping tools from sticking to the concrete. Apply too much release, and you get a puckered, spongy mess. Apply too little, and you get pulling and tearing of the surface. Some applicators have better success stamping the surface first using a clear liquid release and then applying a tinted liquid release immediately afterwards to highlight the texture of the surface. This method tends to work better with more porous surfaces, like stampable overlays.

    Selecting A Filling Material

    Some of the common filling materials used are a sand mixture of cement brands of your choice. Depending on how large your break is, the suitable option is using epoxy fillers or coarse aggregate concrete.

    Epoxy fillers are best suited for splits that are one inch or less and are tailor-made for concrete with a grey color option that will fully complement your cracked terrace.

    For a super-large cracked patio, the mind-boggling question is how to repair large cracks in concrete porch? Well, the cement mixture is the way to go; a cement mix of cement and sand will do the trick.

    How Do You Repair Hairline Cracks In Concrete Patio

    repair hairline cracks in concretecementcementconcretehairline crack

    Hairline cracks in a concrete slab are rarely a cause for concern. They can be controlled, but not eliminated. A crack in a slab of 1/8 inch or less is typically a normal shrinkage crack and not a cause for concern.

    One may also ask, can cracks in concrete be repaired? Wide cracks in concrete are best patched and sealed with a concrete patching compound. Smaller cracks, less than 1/4 inch wide, can be repaired with a concrete caulk or liquid filler. Patching compounds typically are mixed with water and applied with a trowel.

    Secondly, what causes hairline cracks in concrete?

    Hairline cracks generally fall into the static crack category — they don’t move and they’re not going to. They’re typically surface cracks that were caused by one-time events, like drying shrinkage. Tight, static, surface cracks can be coated with most polymer-modified cementitious overlays and never seen again.

    How do you fill gaps in concrete?

    Fill and smooth the jointFill the crack with urethane caulk, similar to what you would use for driveway caulk. It works perfectly as a concrete expansion joint sealant. Snip the opening of the tube at a 30-degree angle, making the opening the same size as your gap.

    Concrete Cracks Caused By Overloading The Slab

    Although concrete is a very strong building material, it does have its limits. Placing excessive amounts of weight on top of a concrete slab can cause cracking. When you hear a concrete mix has a strength of 2000, 3000, 4000, or 5000+ PSI, it is referring to the pounds per square inch it would take to crush that concrete slab.

    When it comes to residential concrete slabs, overload of the actual slab isn’t all that common. Instead, what is more likely to occur is excess overload on the ground below the slab.

    After a heavy rain or snowmelt when the ground below is soft and wet, excessive weight on the slab can press the concrete down and result in cracks. Residential homeowners who place large recreational vehicles or dumpsters on their driveways are more likely to see this type of cracking.

    How Do You Fill & Repair Gaps In Concrete

    Filling gaps in concrete is a straightforward job, and once you’ve done it once, you’ll wonder why you put it off.

    This is how you repair a crack in the concrete using a ready-mixed mortar, like the ones from Amazon that we mentioned earlier.

  • Clean the area thoroughly, making sure it’s free from particles like dust and dirt . The ground also needs to be dry
  • Using something like a mason’s trowel, push the paste into the crack, ensuring it gets right in
  • Press it in firmly to avoid any air gaps. You may want to use a putty knife for this
  • Smooth the surface to the same level as the concrete
  • Allow the mix on the repair to cure, according to the manufacturer’s instructions. It would normally take at least 24 hours. Some people suggest lightly covering the repair with a tarp after a couple of hours, for extra protection while it cures
  • If you’re using a tube of concrete crack sealant, it’s even easier. This is one of those incredibly satisfying jobs and you can easily get a good-looking result. Make sure you choose the color of sealant that’s the closest match to the surface you’re working on. Bluestar, for example, offer two shades of gray.

  • Prepare the sealant bottle as per manufacturer’s instructions (usually, shake well then snip off the nozzle
  • With a steady hand, follow the line of the crack with the nozzle, gently squeezing out the sealant
  • Go over the line with a putty knife, smoothing the ribbon of sealant into the surrounding concrete
  • How To Fix Hairline Cracks In Painted Concrete

    When concrete walls or floors are poured, the water that is used to mix sand and cement evaporates, curing the mixture into a monolithic slab. This process involves a small amount of shrinkage, which can lead to the formation of hairline cracks. Once these concrete surfaces are painted, any cracks that exist will stand out even more. To prevent the cracks from growing and letting moisture in, as well as to keep the surface better-looking, fill the cracks and be done with the problem in no time.

    Types Of Poured Concrete Slab Floors

    Before we describe crack, movement, and damage patterns and diagnosis in concrete slabs, we need to introduce three different types of poured concrete floor slabs.

    We use the three Carson Dunlop Associates Sketches shown here to comment on the occurrence, causes, and significance of cracks and movement in poured concrete slab construction.

    We define types of foundations and their common vulnerabilities also

    How To Apply Surecrete Deep Patch Concrete Hole Patching Leveling Material

    Repair Hairline Crack In Concrete Driveway

  • Clean the surface – Concrete substrate should be completely clear of any grease, oil, old paint, etc.. Otherwise it will not form a good bond.
  • While not always necessary, some areas may need profiling if they are exceptional “tightly trowelled.” Easily be done with another of our Surface Preparation products – SCR.
  • Dampen the surface of the concrete . Then apply a thin coating of SureBond to a small work area so as not to let it dry out.
  • Mix Deep Patch™ with water thoroughly in a large bucket. While working to ensure it does not set up before it can be applied.

  • Apply Deep Level to ONLY the work area where SureBond is present, not dry. Continue following these steps until all sectors have been patched/covered to your satisfaction! Deep Level is typically trowelled into place; however, application methods will vary depending on the project needs.
  • Patches in excess of 2” up to 4” require the introduction of # 8 pea gravel at the rate of 10 pounds pea gravel to 1 – 50 pound bag of Deep Patch™.
  • Base Coat1. Before applying Deep Patch™, the surface should be saturated surface dry with clean water .2. Apply SureBond™ according to the TDS Deep Level

    Patching Coat1. While SureBond™ is still wet, use Deep Level™.2. Apply Deep Patch™ by trowel or squeegee, ensure the product is tightly placed into patched area.

    How To Repair Wide Concrete Cracks

    The secret to fixing wide concrete cracks is to undercut the sides of the crack to give it an inverted “V” shape. This helps the repair material to “key” into the crack, creating a mechanical bond in addition to the chemical bond between the patch material and the concrete.

  • Chisel the crack with a hammer and masonry chisel to widen the base of the crack and to dislodge any loose material from the old concrete.
  • Remove all debris from the crack, using a wire brush. If desired, clean the crack with a pressure washer or a garden hose and spray nozzle.
  • Remove all water and debris from the crack with a wet/dry shop vacuum or a brush. Work carefully to remove all dust and grit from the crack. It’s OK if the surfaces are wet, but there should be no pools of water.
  • Mix the concrete patching compound, following the manufacturer’s directions.
  • Trowel the compound into the crack. Stab the trowel into the compound to remove air pockets and help work the patching material deep into the crack. Fill the crack up to the surrounding concrete surface. 
  • Smooth the surface of the patch with the trowel, feathering the compound into the surrounding concrete.
  • Brush the surface of the patching compound with a dry paintbrush to texture the surface, if desired.
  • Let the compound cure as directed.
  • Paint or seal the surface of the patch and surrounding area, if desired.
  • Best For Very Small Hairline Cracks: Concrete Glue

    For very small cracks that are not too serious, you can try using something simple like concrete glue or cement glue –some form of a concrete crack filler.

    This substance is otherwise known as liquid cement or liquid concrete. It’s almost like super glue, except when it dries, it turns into concrete.

    Remember that it comes in small bottles and is really only ideal for very small repair jobs.

    If this sounds right to you, once the crack has been properly prepared, fill it using the cement or concrete glue. You then need to let it dry and cure according to the instructions on the specific product you chose to purchase.

    Fixes For Your Cracked Concrete Patio

    • January 25, 2019

    While concrete patio installations can be beautiful and functional, they often develop cracks, and patio repair is something many homeowners face with their outdoor patios. Cracks in concrete not only detract from the look of your patio, but cracks can also lead to potential problems in the future as moisture begins to seep into the concrete. Luckily, there are a few easy ways you can repair your cracked concrete patio and prevent further damage.

    Step 1: Repair A Foundation Crack With An Epoxy Sealer

    We repaired a foundation wall, which had an 8-ft.-long crack that leaked water into the basement during periods of heavy rainfall. To permanently patch the crack we used an epoxy-injection system from Polygem, called the Liquid Concrete Repair Kit .

    Each kit contains a two-part epoxy crack sealer, two 10-oz. tubes of Liquid Concrete Repair , a viscous epoxy that comes in a caulk-type cartridge, and seven plastic injection ports that deliver the LCR deep into the crack. There’s enough material in each kit to repair a 1/16-in.-wide x 8-in.-deep x 8-ft.-long crack.

    Before you start, check to make sure the crack is dry. If the crack is slightly damp, dry it with a blow-dryer, then wait 15 minutes. If it remains dry, proceed with the repair. However, if the dampness returns, water is still seeping into the crack and you’ll have to wait for it to dry out on its own.

    First, scrub the crack clean of any loose concrete, paint or old crack filler using a wire brush. Remove all dust and debris with a shop vacuum.


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