What to Do When You Find a Foundation Crack

Finding a crack in your foundation is unsettling. Most homeowners' first reaction is panic — or denial. Neither helps. Here's what to actually do, in the right order.

Step 1: Don't panic (but don't ignore it)

Most foundation cracks aren't emergencies. Most are repairable permanently and relatively affordably. But ignoring them tends to turn minor cracks into major ones, so you do need to address it — just methodically.

Step 2: Document what you see

Before you do anything else, get out your phone. Take photos of:

• The crack itself, from a foot or two away
• Close-up shots showing the width of the crack
• Wider shots showing the crack's location on the wall
• Any water staining, efflorescence (white deposits), or moisture around the crack
• Any other cracks you can find throughout the basement or crawl space

This documentation is useful for contractors diagnosing the issue — and if the crack worsens, for tracking how fast.

Step 3: Classify the crack

Horizontal cracks

More concerning. Indicate pressure from outside the foundation pushing against the wall. Often accompanied by bowing. Need to be addressed soon.

Vertical cracks

Usually less concerning unless they're wider at the top or bottom. Often from curing, shrinkage, or minor settlement. Still need sealing if they leak.

Stair-step cracks

Moderately concerning. Show up in block walls when the foundation settles unevenly. Usually need structural assessment.

Diagonal cracks

Depends. Diagonal cracks from a corner indicate differential settlement. Worth an inspection.

Step 4: Check the width

Measure the widest part of the crack. A business card is about 0.5mm. A quarter is about 1.7mm. A crack wider than 1/4 inch (6mm) usually indicates serious movement.

Step 5: Check for water

Is the crack wet? Actively dripping? Shows water staining below it? Wet cracks are more urgent — they're already letting water in, which means the damage is ongoing.

Step 6: Look for related symptoms

Other signs that the foundation is actively moving:

• Doors or windows sticking in the affected area
• Drywall cracks upstairs, especially above doors and windows
• Sloped or uneven floors
• New gaps between wall and ceiling or wall and floor
• Exterior gaps or cracks around windows, chimneys, or trim

If you're seeing multiple symptoms, this is probably not just a surface crack.

Step 7: Get an inspection

At this point you've got good information. Call a foundation specialist — not a general contractor or handyman — for a proper inspection.

A real inspection should include:

• A full walkthrough of the basement/crawl space
• Photos and measurements of every crack and any related signs
• A written report with findings
• A clear explanation of the cause, in plain English
• A written estimate with zero pressure

What NOT to do first

• Don't patch it yourself with concrete caulk. You'll make the real repair harder and you won't solve the underlying issue.
• Don't call the first contractor who shows up with a pressure sales pitch. Get a real diagnosis first.
• Don't finish the basement. You'll be tearing it out if the crack worsens.

The wrong move isn't fixing the crack too aggressively. The wrong move is ignoring it or patching over it and hoping.

Schedule a free foundation inspection — we'll tell you honestly whether it's a repair, something to monitor, or nothing to worry about.

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