12 common problems with concrete slabs and how to address them

Have you got an issue with concrete slabs on your property? Read on for 12 common problems and how to fix them.

An integral part of most structures, concrete is one of the strongest construction materials. Over time, new concrete slabs show signs of wear and tear on driveways, walkways, and sidewalks. They affect the aesthetics and appearance of concrete surfaces.

Owners should know about the common concrete issues and how to fix them with the help of a local sidewalk repair contractor. In this article, we will go over the most common concrete slab problems and their solutions.

12 common concrete slab issues and how to fix them

1) Blistering

A common concrete issue, blistering leads to small, raised, and hollow bumps on the concrete surface. Insufficient venting, incorrect concrete mix, and delayed finishing are the common causes of blistering.

How to fix blistering

Appropriate venting will help fix blistering. You can prevent blisters from forming by using a roller during the finishing process. This would push out trapped air.

Make sure that you begin finishing once all the water evaporates from the surface. This, too, helps in avoiding air-trapping

2) Cracks 

Concrete cracks are the most common issue in driveways, garages, sidewalks, and pool decks.

How to fix cracks on concrete

  • Caulking: You can use concrete-specific caulk to seal cracks and fill gaps to prevent moisture infiltration in the surface.
  • Epoxy or Polyurea Crack Filler: Interior concrete cracks need different treatment than exterior concrete slabs. You can fill them with epoxy or polyurea repair liquid to seal and strengthen the concrete.
  • Patching: Although a temporary fix, using grout or mortar can help fill cracks. There is the possibility of reopening due to concrete contraction or expansion.

3) Chipped or broken concrete slab corner

Owing to natural slab movements or tension due to steps or slabs can lead to large chunks of concrete breaking. Drilling handrails also causes slabs to break off from the corners.

How to fix chipped or broken concrete slab corner

Additional Concrete or Patching Kit: Using extra concrete or a special patch kit could offer a temporary fix to the broken concrete slab corner. However, since concrete contracts and expands naturally, it will break off again. This could be dangerous on steps because the patch might break with use.

Replacing the entire concrete slab or section is the ideal solution. If your driveway is cracked and you are having trouble pulling in without scraping your car, it might be a good idea to get a Smooth Curb driveway ramp until you can permanently fix the problem (if possible).

4) Crazing

Crazing is the thin web-like cracks on the concrete surface. These cracks are shallow. However, they affect the look of your concrete driveway or sidewalk. Crazing occurs due to excessive water content, improper curing, or rapid drying.

How to prevent crazing

  • Proper Curing: Ensure proper curing techniques so concrete hydrates fully and strengthens gradually.
  • Curing Compounds or Membranes: You can reduce the risk of crazing by applying membranes or curing compounds to retain moisture in concrete and boost proper hydration.
  • Avoid Surface Overflow: To avoid crazing, reduce excessive troweling or finishing.

5) Curling

Curling occurs when the edges of the slab rise or curl. It happens due to an increase in temperature or moisture content between the top and bottom surfaces of the slab. The top of the concrete slab dries faster than the bottom, causing a higher degree of shrinkage on the surface.

We recommend you should meet with a sidewalk repair services provider in NYC when you are going to install new concrete slabs. This results in the curling of concrete.

How to prevent curling

  • Control Joints: Installing control joints at regular intervals would help with some degree of shrinkage, preventing curling.
  • Ensure Uniform Drying: Practice a curing regimen that ensures the concrete slab dries uniformly. After placing the slab, keep it moist for a sufficient time, and use moisture-retaining methods like curing blankets.

6) Delamination

Delamination leads to separation along the concrete slab plane. As a result, a thin horizontal layer peels away from the surface. Since it is hidden from view under the surface, delamination is not easy to detect or address.

How to reduce the risk of delamination 

Reducing the risk of delamination involves following the correct steps during concrete handling:

  • Adequate Curing Conditions: Ensure sufficient moisture levels are maintained to prevent rapid drying that causes delamination.
  • Uniform Aggregate Distribution: Avoid creating a weak layer that can delaminate by ensuring a uniform distribution of aggregates.
  • Avoid Surface Overflow: Start the finishing process only after evaporation of bleed water.

7) Discoloration

Concrete discoloration can occur due to numerous factors like exposure to chemicals, improper mixing, insufficient curing time, or environmental factors. Discoloration makes the concrete appear uneven and blotch.

How to address discoloration

  • Concrete Sealer: Using a high-quality concrete sealer helps protect the surface from stains and moisture.
  • Concrete Stain: Concrete stain improves and enhances the appearance of concrete and gives lasting color.

Avoid using chemicals or materials that potentially lead to discoloration.

8) Efflorescence

Efflorescence is a common concrete issue where a white powdery mass appears on the surface. It is caused by water infiltration in concrete, excess water in the concrete mix, or rain or dew in the environment. Once the water evaporates, this residue is left behind.

How to address efflorescence

This requires several steps:

  • Use a specialty cleaner or mild acid to remove the white substance. Follow the instructions. Rinse thoroughly.
  • Apply a high-quality sealer after cleaning the surface. This will block pores and prevent water from seeping into concrete.
  • Ensure proper drainage systems to prevent water accumulation. Ensure proper sealing and moisture control in concrete installations.

9) High permeability

Permeability is the degree to which air and water pass through a material. High permeability in concrete leads to numerous structural issues like decreased durability, corrosion, and freeze-thaw damage.

How to prevent and remedy permeability

  • Ensure Adequate Concrete Curing: Ensure perfect concrete curing to reduce surface porosity and decrease permeability.
  • Appropriate water-cement ratio: Maintain a balanced water-cement ratio in the concrete mix to reduce permeability.

10) Scaling

The peeling or flaking of concrete surfaces is called scaling. It mostly occurs because of freeze-thaw cycles, inferior quality materials, and freeze-thaw cycles.

How to treat scaling

  • Address Underlying Problems: Repair the underlying problems like poor surface preparation or poor installation to avoid concrete scaling.
  • Concrete Sealer: Using a high-quality concrete sealer offers a protective barrier preventing moisture infiltration and lessening chances of scaling.
  • Better Surface Drainage: Avoid water accumulation on the concrete surface with proper drainage to reduce the risk of scaling.

11) Settlement

When the underlying soil compresses, it causes the concrete slab to become uneven or sink.

How to address settlement

  • Adequate Drainage: Ensuring proper drainage can reduce the impact of soil erosion and water infiltration, lessening the risk of settlement.
  • Better Soil Composition: You can prevent concrete settlement issues by properly compacting the soil before pouring concrete.
  • Slab jacking or Mud jacking: You can lift and level the concrete slab by slab or mud jacking to restore alignment.

12) Spalling

The chipping or flaking of the concrete surface layer is called spalling. Small pieces of concrete break and expose the underlying aggregate. Freeze-thaw damage, poor installation, and corrosive substances cause spalling.

How to fix spalling

Fixing spalling is a step-by-step process:

  • First, use appropriate tools to remove the damaged concrete.
  • Clean the area vigorously to remove dust, debris, or loose particles.
  • Use a suitable coating or repair mortar on the surface to ensure it sticks well and is compatible with the existing concrete.

How to prevent and mitigate concrete issues

Proper knowledge and understanding of the underlying reasons behind concrete slab issues are necessary to prevent and mitigate concrete issues. You can reduce the risk significantly by following preventive measures. However, appropriate tools and materials are needed to restore the concrete to its former condition.

It is best to hire professional Sidewalk Repair NYC services for your concrete projects. Rest assured that they will maintain the integrity and aesthetics of your concrete surfaces.