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April 12, 2024

How to Fix Foundation Cracks?

How to fix foundation cracks h&n basement worx

Foundation cracks are common in homes and can happen for several reasons:

Settling – All homes settle over time as the soil underneath naturally compacts. Differential settling is when one part of the foundation settles more than other parts, causing cracks.

Soil Movement – Expansive soils that swell and shrink with changing moisture levels can exert pressure on foundations. This movement causes cracks.

Tree Roots – As tree roots grow near the foundation, they can push against the foundation and crack it. Large trees close to the home are the biggest culprit.

Poor Drainage – Standing water against the foundation keeps soil saturated. This causes the soil to expand and contract, leading to cracks.

Seasonal Changes – Seasonal freezing and thawing of the ground, as well as expansion and contraction from heat and cold, puts stress on foundations. Over time, this leads to cracking.

Types of Foundation Cracks

There are several common types of foundation cracks:

Horizontal Cracks

Horizontal cracks run laterally along the foundation wall. They indicate the foundation is settling unevenly, often due to expansive soils that swell and shrink with changing moisture levels. Horizontal cracks tend to gradually widen over time if not repaired.

Vertical Cracks

Vertical cracks run up and down the foundation wall. They are caused by a shifting foundation, often due to clay soils expanding or inadequate foundation support. Vertical cracks can allow water to penetrate the foundation.

Diagonal Cracks

Diagonal cracks run at an angle across the foundation. They indicate foundation settlement in a particular area, such as a corner. Diagonal cracks are especially concerning because they show instability in the foundation.

Stair-Step Cracks

Stair-step cracks occur vertically in a stairstep pattern. They are caused by a substantial foundation settlement issue on one side. Stair-step cracks require professional repair to stabilize the foundation.

Poured Contraction Joint Cracks

These are vertical cracks that occur at poured contraction joints in concrete foundation walls. They allow for natural expansion and contraction but can admit water if opened too wide. Sealing contraction joint cracks helps protect the foundation.

When to Repair Foundation Cracks

It’s important to repair foundation cracks as soon as possible, before the cracks have a chance to widen and cause further structural damage. The sooner you address foundation cracks, the easier and more affordable the repairs will be.

Here are some key reasons you’ll want to repair foundation cracks right away:

  • Prevent Further Damage – Unrepaired cracks can worsen over time as the foundation continues to settle. This leads to larger cracks that compromise structural integrity. Early repairs prevent extensive repairs later.
  • Stop Water Intrusion – Cracks allow water to seep into the foundation, leading to erosion, mold growth, and damage. Prompt repairs seal out moisture.
  • Improve Appearance – Widening cracks are unsightly. Repairing them early keeps your foundation looking its best.
  • Maintain Home Value – Foundation cracks lower curb appeal and home value if left unaddressed. Timely repairs maintain the value of your investment.
  • Reduce Safety Risks – Large foundation cracks can destabilize walls, floors, and the overall structure. Repairing quickly returns your home to a safe condition.

In summary, it’s always better to repair foundation cracks sooner rather than later. The small investment in prompt repairs will pay off by preventing much larger expenses down the road. Address cracks right away for safety, aesthetics, and long-term home value.

DIY Foundation Crack Repairs

DIY repairs are suitable for minor cracks less than 1/4 inch wide. Larger cracks should be repaired by professionals.

To repair minor cracks yourself:

Clean the Crack

Use a wire brush to remove any loose material or debris from the crack. Vacuum the area to remove all dust. Wipe clean with a damp cloth. Proper cleaning allows the repair compound to fully bond with the concrete.

Fill the Crack

For small hairline cracks, use a concrete crack filler compound, hydraulic cement, or epoxy filler. Press the filler deeply into the crack using a putty knife. Overfill slightly to allow for shrinkage as it cures. Follow the product instructions for drying time before sanding flush.

For slightly larger cracks up to 1/4 inch, use a concrete repair caulk or patching compound. Press it into the crack forcefully to fill completely and smooth the surface. Allow proper curing time before sanding smooth.

Seal the Crack

Once filled and smoothed, apply a concrete crack sealer to the surface. This waterproofs and reinforces the repair. Use a paintbrush to coat the entire crack and surrounding area. Allow the sealer to fully cure for 24-48 hours before exposing to weather or heavy use.

Sealing is an essential step to prevent further cracking and damage from moisture penetration. Reapply sealer every 2-3 years.

Professional Foundation Crack Repairs

For more serious foundation cracks or widespread foundation damage, it’s best to hire a professional foundation repair company. Professionals have the expertise and equipment to fully evaluate the root cause and recommend the right solutions. Here are some common methods used:

Epoxy Injection

Epoxy injection involves injecting a high-strength epoxy resin into the crack. The epoxy bonds to the concrete and essentially glues the crack back together. Epoxy injection works for cracks wider than 1/8th inch. The crack is sealed on the surface with an adhesive port, then the two-part epoxy is pumped through the port until it fills the crack. After curing, the port is removed and the crack is sealed.

Helical Pier Installation

Helical piers are threaded steel shafts that are screwed into the ground next to the foundation to stabilize it. They act like mini piles anchored deep in the ground. Helical piers can lift and realign sinking foundations and provide reinforcement. They are installed with truck-mounted equipment.

Wall Bracing

For bowed or leaning foundation walls, steel wall braces may be installed. The steel rods are anchored to the foundation wall and adjustable brackets on the basement floor. Tightening the rods straightens and supports the wall. Wall braces are often used along with other repairs.


Slabjacking involves pumping a cement grout mixture under sunken concrete slabs to lift them back into position. Holes are drilled into the slab and grout is pumped through until the slab levels out. Slabjacking is less invasive than replacing the slab.


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