How to fix low spots in concrete slab (2024)

If you need to level low spots on your floor, use a concrete patching compound. The patching compound also works well to repair any cracks that formed when the concrete settled. You don’t need many tools for this project, but you do need to wear protective gear for your eyes and hands. Work in a well-ventilated area.

How do you repair a dip in a concrete slab?

Sweep the surface of the floor. Use a concrete degreaser on any area of the concrete that has oil stains, scrubbing away the stain using a stiff-bristled brush. Mop the floor using a chemical concrete cleaner. The cleaner will etch the floor slightly, increasing the adherence of the leveling compound.

How do you fix concrete craters?

Quote from Youtube video: So it's pretty simple straightforward sand mixture liquid mixture says the burst seal roll. In this direction.

How do you Relevel a concrete slab?

Quote from the video:
Quote from Youtube video: You take a straight edge or a screed. And you run it across the rails leveling the compound and making it even with the top of the rails using the rails as guides.

How do you fix concrete depression?

  1. Clean the area around the depression by scrubbing it with detergent and water. …
  2. Gauge the depth of the depression using a straightedge, such as a straight two-by-four. …
  3. Fill the depressions with self-leveling concrete filler.
  4. How do you fix concrete ponding?

    Quote from the video:
    Quote from Youtube video: And he says I was told that I could use a product called concrete resurfacer.

    How do you fix floor dips?

    There are multiple ways to fix a floor that sags and dips.

    1. Pour Self-Leveling Underlayment. Pour self-leveling underlayment in the problem area. …
    2. Sister the Joists. …
    3. Prop Up the Joists. …
    4. Lay Down New Hardwood.

    What is best to patch concrete?

    The Best Concrete Patches of 2022

  • Best Vinyl. Damtite 04012 Gray Bonds-On Vinyl Concrete Patch.
  • Best Overall. Red Devil 0644 Pre-Mixed Concrete Patch.
  • Runner-up. Damtite 04072 Concrete Super Patch Repair.
  • Best Bang for the Buck. Quikrete #862013 5.5 Oz Concrete Repair.
  • Best for Floors. …
  • Best for Walls. …
  • Best Acrylic. …
  • Best Vinyl.

What is the best way to patch concrete?

Quote from the video:
Quote from Youtube video: Use a margin trowel or putty knife to thoroughly stir a concrete patching compound.

What to use to fill concrete holes?

Most holes can be fixed with a quality mortar mix, although you should use one with a crushed stone aggregate to fill holes over 1 in (2.5 cm) deep. Treat holes as soon as you find them so you can prevent water and rodents from further damaging the concrete and getting into your home.

Can you pour concrete over concrete?

You can put new concrete over old concrete. However, unresolved issues with your old concrete, such as cracks or frost heaves, will carry over to your new concrete if not taken care of. In addition, you must pour it at least 2 inches thick.

How do you blend old and new concrete?

It’s virtually impossible to match new concrete and old concrete. Your best option is to apply a concrete overlay across both the new and old surfaces. However, if this is not an option, to lessen the effect of mismatched concrete, you can: wash the old concrete to remove dirt buildup.

How do you fix a sinking slab?

The least expensive way to raise a sunken slab is to inject a combination of dirt, aggregate and Portland cement through holes in the surface. This process is called mud jacking, and it’s a job best left to pros with the equipment to do it, because the material has to be injected under pressure to do the job.

How do you fix a sunken patio slab?

Quote from the video:
Quote from Youtube video: Your putty knife see while these paving stones are moving around insert a couple of putty knives in there and just want to pry it up slowly.

How do you fill uneven concrete?

You would fill in the wedge of the lower section by framing out borders along the edges of the original slab surface. Then you would overlay new concrete material to make it level again with the other piece of concrete. This could be done by DIY or hired out to a contractor.

How do you fix a dip in a patio?

Quote from the video:
Quote from Youtube video: Use a brick kind of pack everything in place. As. I want this brick to be just a slight bit higher than the rest of the bricks on the outside.

How do you fix an uneven concrete patio?

Use a Concrete Leveling Compound

For concrete patios that are only slightly uneven, a concrete leveling compound is often enough to relevel the slab. This process begins with a thorough cleaning of the concrete.

How do you level a sloping patio?

Measure the slope, by tying a string to a stake inserted just outside the lower end of the patio site. Extend the length of string to the opposite edge of the patio surface. Use a level to adjust the string’s height on the stake so the string hangs taut and perfectly level between the two surfaces.

Why is my patio sinking?

Erosion. Water erosion is one of the most common reasons for a patio to sink or dip over time. Below all of the foundation gravel and sand is all-natural soil. This soil can be affected by water erosion causing a dip in your patio.

Why do patio slabs sink?

A section of paving or even a single slab might sink because of small ground movements or heavy use, and this can make rainwater collects in puddles.

What is polymeric sand?

Polymeric sand is a material used to fill paver joints, the empty spaces found between each paver, tile or natural stone. It is sometimes called jointing sand, paver sand or hardscape sand. Jointing sand is made up of fine grains, to which manufacturers add a mixture of specific additive particles.

When should you not use polymeric sand?

#6 – Too Narrow or Too Wide Joints

The sand is simply pushed out of the joints. This is why we don’t recommend using polymeric sand on extremely narrow joints. Similarly, too-wide joints can lead to washout, because they allow too much water flow during the activation process.

What can I use instead of polymeric sand?

Builder’s Sand

Builder’s sand is the most common replacement for polymeric sand, as it is easy to access and not expensive. It is used heavily in construction projects, hence its name. Because this sand is very coarse, you will need to use it regularly. You’ll have to reapply it for years as it settles.


  1. Can pavers set with polymeric jointing sand be powerwashed?
  2. Leave Polymeric Sand Until Tomorrow?
  3. What sand do I use to re-secure pavers?
  4. Polymeric sand issue
  5. What kind of filler was used for this patio?
How to fix low spots in concrete slab (2024)


How to fix low spots in concrete slab? ›

Using concrete leveling compound is a great idea for do-it-yourselfers, and it's a great way to correct smaller, less severe low spots. For dips and sags that are fairly localized, using leveling compound can be a fantastic, low-cost solution.

What causes low spots in concrete? ›

Low spots are exactly what they sound like, and they will affect drainage and serviceability of the slab. They are generally caused by poor forms and poor screeding, overly wet concrete, poor lighting during placement and finishing, and poor placement and finishing.

How do you drain a low spot in a concrete patio? ›

If your patio is completely flat and has low spots where the water collects, it needs to be angled or sloped slightly so the water will run off the surface, much like a roof gutter is sloped to direct water to the downspout. Find concrete patio contractors near me who can assess and fix my drainage problems.

How do you raise the level of a concrete slab? ›

Raising by injecting polyurethane is used to raise and support sunken concrete. Holes are drilled and material is pumped under the sunken concrete. Foam is significantly lighter and cures faster than slurry mud mixes.

Can a low spot in concrete be fixed? ›

Using concrete leveling compound is a great idea for do-it-yourselfers, and it's a great way to correct smaller, less severe low spots. For dips and sags that are fairly localized, using leveling compound can be a fantastic, low-cost solution.

What can I use to fill low spots in concrete? ›

Happily enough, leveling uneven concrete slabs has an easy fix that won't sacrifice your headroom. The easiest way is to use a self-leveling compound, also called liquid floor underlayment or floor resurfacer, within sections of level-cut rails.

How do you level a sinking concrete slab? ›

How To Lift a Concrete Slab
  1. Step 1: Drill Dime-Sized Holes. The lifting process starts with drilling dime-sized holes into the sunken slabs. ...
  2. Step 2: Install the Delivery Port. ...
  3. Step 3: Pump the Lifting Material. ...
  4. Step 4: Monitor the Raising. ...
  5. Step 5: Patch the Holes.

Can you pour self leveling concrete over existing concrete? ›

Yes, you can put self-leveling concrete over your existing uneven concrete.

What happens if water sits on concrete? ›

Damage to sealant is likely, which can further lead to mold and/or algae thriving. If the water pooling on the concrete happens to freeze during the colder months, it will expand and make cracks or holes even larger than before.

Will water drain through concrete slab? ›

Concrete is already a porous material. This means that water could find its way through your concrete by itself. But, if you have cracks or cove joints that aren't sealed properly, water will use those openings to enter your foundation.

How do you remove water from under a concrete slab? ›

Drying Methods for Wet Concrete Slab Floors

If the leak is small enough, you can remove the water by absorbing it with towels or other materials that can soak up water. If the leak is large, a shop vac could be used to dry out the area.

What are the dimples in concrete? ›

Concrete pitting is when the surface of a concrete structure begins to deteriorate. It's defined by a cluster of small holes that appear on the surface of the concrete. It's an extremely common problem in construction that occurs because of a problem with the way the concrete was produced.

How do you fix ghosting in concrete? ›

Antiquing Concrete Stain is a great option to blend the colors on more porous floors. Concrete dye can also be used to cover imperfections and accent the floor as needed. Topical stains can disguise the tile ghosting still visible after grinding.

Is efflorescence on concrete a problem? ›

Efflorescence is the white chalky powder that you might find on the surface of a concrete or brick wall. It can be a cosmetic issue, or it can be an indication of moisture intrusion that could lead to major structural and indoor air quality issues.

What are the signs of deterioration in concrete? ›

Problems illustrated include: plastic cracking, random cracks, crazing, alkali-aggregate reaction cracks, honeycombing, sand streaking, scaling, spalling, dusting, popouts, water cavitation, and water erosion.

Top Articles
Latest Posts
Article information

Author: Arielle Torp

Last Updated:

Views: 5547

Rating: 4 / 5 (41 voted)

Reviews: 80% of readers found this page helpful

Author information

Name: Arielle Torp

Birthday: 1997-09-20

Address: 87313 Erdman Vista, North Dustinborough, WA 37563

Phone: +97216742823598

Job: Central Technology Officer

Hobby: Taekwondo, Macrame, Foreign language learning, Kite flying, Cooking, Skiing, Computer programming

Introduction: My name is Arielle Torp, I am a comfortable, kind, zealous, lovely, jolly, colorful, adventurous person who loves writing and wants to share my knowledge and understanding with you.