How To Repair Foundation Cracks (2024)

By Amanda Lutz Updated February 5, 2024

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Foundation cracks can compromise the structural integrity and safety of your home. Identifying and addressing the issue promptly prevents further deterioration and costly repairs. You may notice foundation cracks in your basement wall or crawl space. Sometimes, they’ll be more evident through settling and drywall cracks inside your home. Our guide below covers the immediate steps to take to safeguard your property and secure your living environment.



Foundation Cracks

Understanding the difference between structural and non-structural cracks is an essential first step. Structural cracks are wider than 1/4 inch and can cause damage to other parts of the house. Non-structural cracks are typically narrower and don’t have as much of an impact.

For DIY enthusiasts, epoxy injections and hydraulic cement patches may fix minor issues until a professional can be consulted. If the cracks you notice are not structural, there’s a good chance the home has good bones. You can still improve cracks cosmetically without worrying about the foundation.



Assessing Your Foundational Crack

To accurately assess the type of crack, examine the following characteristics closely:

Minor vertical hairline cracking may not require professional intervention if no other signs point to significant damage. Monitor them to see if they spread or get worse over time.

If there are cracks in your foundation, ask the following questions:



Gathering Supplies

Gather suitable materials before repairing foundation cracks. Depending on the type of crack, you may need different supplies to address the issue effectively. Here are some essential materials you may need:

Note that different foundation cracks require specific approaches and materials for long-lasting results. For example, hairline cracks often benefit from epoxy or polyurethane injection methods due to their ability to penetrate deeply into narrow gaps and create a strong bond across multiple layers of concrete.



Prepping Cracks for Repair

To ensure the best repair for your foundation cracks, thoroughly clean the crack using a wire brush or vacuum cleaner. Then, widen the gap with a hammer and chisel to create bonding space for the repair material. Be cautious not to overdo this process, as it may weaken the surrounding structure.

After widening, use compressed air or a damp cloth to remove any dust or debris caused by chiseling. Scrutinize the cracks to detect additional needs, such as filling voids or injecting epoxy resins. Before applying sealant or patching compound, ensure all surfaces surrounding the crack are moistened but not saturated with water. This helps secure proper bonding between new and existing materials while preventing premature drying of applied compounds.

If your foundation crack has caused settling inside your home, you might find some cracking in your drywall and plaster. Repairing plaster is a simple project.



Repairing the Foundation Crack

Cracks on a home’s foundation come in various shapes and sizes. We’ll explain the most common foundation cracks and how to repair them below.

Diagonal Cracks

Clean the area around a diagonal crack in your foundation with a wire brush and vacuum to remove debris. Widen the gap slightly with a chisel or angle grinder to create a V-shaped groove for better adherence. Inject an epoxy or polyurethane filler into the groove as instructed by the manufacturer. Let it dry, smooth excess material, and paint over it for an even finish. Check the foundation regularly for new cracks and address them quickly to prevent further damage.

Hairline Cracks

If you notice a thin break in your foundation, take care of it immediately to avoid further damage. Clean the area surrounding the crack with a wire brush and vacuum up debris. Use a caulk gun or syringe to inject an epoxy/polyurethane material into the crack until it is filled. Let the product dry by following the manufacturer’s instructions, and use a putty knife to clear away any excess material. Monitor the repaired crack for stability and contact a specialist if you see any signs of expanding or recurring cracks.

Horizontal Cracks

To repair a horizontal crack on the foundation, assess the damage first, scrub the crack with a wire brush, and remove any loose material or mortar. Inject epoxy or polyurethane into the crack to seal it. Give the material time to heal before looking for signs of cracks or water leakage. If needed, consult a professional contractor.

Stair Step Cracks

A stair-step crack is a common form of foundation damage that looks like a set of stairs. Analyze the severity and decide if professional help is needed. DIY repair is possible with epoxy or polyurethane foam if the crack is slight. However, these approaches may only provide temporary fixes. Consult a specialist for long-term stability and prevention of further damage.

Vertical Cracks

To fix a vertical crack in your foundation, clean the crack of any debris or dirt using a brush or vacuum. Then, apply an epoxy or polyurethane injection filler as instructed by the manufacturer. Give it enough time to dry and cure. Watch for signs of recurrence or the need for further repairs.



Sealing the Repaired Crack

Select a high-quality, flexible sealant explicitly made for foundation repair to seal the repaired crack properly. Clean and dry the damaged area before applying the sealant with a caulk gun or trowel, filling in the gap and smoothing any excess. Let the sealant dry completely according to the manufacturer’s directions before taking other steps to complete your foundation repair.



Preventive Measures to Avoid Foundation Cracks

Here are some measures you can take to prevent foundation cracks:



DIY vs. Pro

DIYers with some experience can often handle minor cracks (less than 1/4 inch) when repairing foundation cracks. For larger and more severe cracks, we recommended calling a foundation repair specialist. Their expertise and equipment allow them to accurately assess damage and provide long-lasting solutions for the safety of your home.



Our Recommendation

Be cautious and consider the extent of the crack before attempting to repair it. We recommend consulting a certified structural engineer or qualified foundation expert to assess the situation.

DIY solutions, such as epoxy injections or concrete crack sealants, can be applied to minor cracks with no signs of shifting soil or structural damage. In cases where the cracks are deeper and more severe, licensed contractors who specialize in foundation repair should be consulted. More advanced repair methods might be necessary for extensive cracking from external factors, such as water infiltration or inadequate drainage systems.



Foundation Crack Repair FAQ

Why do foundation cracks happen?

Foundation cracks often occur due to the following:Environmental factors (e.g., freeze-thaw cycles)Poor construction (e.g., not appropriately compacted or low-quality materials)Soil-related issues (e.g., settlement and shrinkage)

What is the difference between a foundation crack and a foundation settlement?

A foundation crack is a visible break in a building’s foundation, often caused by pressure or stress. Foundation settlement is the process by which a building’s foundation sinks or shifts due to changes in the underlying soil, potentially leading to cracks.

How long will a cracked foundation last?

The lifespan of a cracked foundation depends on the crack’s severity and the quality of the repair. It can serve its purpose for many years if repaired with quality materials and techniques. Address the underlying issues causing the cracking for long-term stability.

How much does it cost to fix a foundation crack?

The cost to fix a foundation crack can vary depending on the severity and location of the crack and whether there are underlying issues that also need addressing. On average, homeowners can expect to pay between $350 to $4,000 per crack for professional repairs. However, extensive repairs and structural reinforcements can cost more.