The short answer
Start with the Cause
Before you buy any filler, figure out what made the crack. Hairline cracks often come from concrete shrinkage as it cures. Wider cracks or ones that keep growing may point to soil movement, poor drainage, or a settling foundation.
Check the crack's direction and width. Vertical cracks are sometimes less alarming than horizontal ones. Look for signs of water staining or efflorescence, a white powdery residue, which means moisture is moving through the crack.
- Measure the crack width with a tape or feeler gauge.
- Note if the crack is active by marking the ends and checking monthly.
- Look for uneven floors or sticking doors near the crack.
- Check outside for downspouts dumping water against the foundation.
- Feel for dampness or see water stains around the crack.
When DIY Makes Sense
For cracks under a quarter inch wide that are stable and dry, you can patch them yourself. Use a polymer-modified concrete patching compound or a masonry caulk designed for foundation walls. Clean out loose debris first with a wire brush and rinse with water.
Apply the patch with a trowel or caulk gun, pressing it into the crack. Smooth the surface and let it cure. This kind of repair is mostly cosmetic. It keeps water from getting into the gap, but it does not fix the underlying cause.
When to Call the Pros
Call the pros if the crack is wider than a quarter inch, if it is growing, or if you see water coming through. Also call if the foundation has shifted, you see stair-step cracks in brick, or the floor is noticeably uneven. These signs point to a structural problem.
The pros will inspect the foundation, the soil, and the drainage around your home. They can identify why the crack happened and recommend a repair that addresses the cause. A temporary patch on a structural crack can hide the problem and let water keep damaging the foundation.
Water and Your Foundation
Water is the biggest enemy of foundations. In a humid subtropical climate with spring hail and thunderstorms, heavy rain can saturate the soil and create pressure against your foundation walls. That pressure can cause cracks to widen and new ones to form.
Check your gutters and downspouts. Make sure they carry water at least five feet away from the house. Grade the soil so it slopes away from the foundation. Fixing drainage can stop a crack from getting worse, even if you can't fix the crack itself.
What the Pros Usually Do
For structural cracks, the pros may inject epoxy or polyurethane foam into the crack to seal it and bond the concrete. They might also install carbon fiber straps or push piers to stabilize the foundation. For water issues, they may recommend exterior waterproofing or interior drainage systems.
Soil movement from moisture changes can shift a foundation. A foundation repair often involves more than just filling the crack. The pros will assess the whole situation and give you a plan. You can then decide what to do based on the severity.
Water damage does not wait
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Call Now (469) 698-4610Frequently asked questions
How do I know if a foundation crack is serious?
A serious crack is usually wider than a quarter inch, active, or accompanied by uneven floors or sticking doors. Water seeping through is a red flag. If you are unsure, have a professional inspect it. They can tell you if it is cosmetic or structural.
Can I just fill the crack with caulk?
For hairline cracks, a masonry caulk can work as a temporary seal. But it won't fix the cause. If the crack is structural, caulk will just crack again. Use a proper patching compound for small cracks and let a pro handle anything bigger.
Will my insurance cover foundation repair?
Policies vary, and your insurer decides what is covered. Foundation damage from water often depends on the cause, such as a sudden pipe leak versus gradual soil movement. Check your policy and talk to your insurance company. They will let you know what is included.