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Found a Crack? What to Do in the First Week

Posted October 28, 2026 · Verified

Most cracks are not emergencies, and the first week is for gathering information, not for repairs. This checklist is built from inspector and concrete-industry guidance.

Day 1: record it before you touch it

  1. Photograph the crack with a coin or ruler beside it, and include the date in the shot or the file name.
  2. Take a wider photo so its location is clear: which wall, how far from a corner, window or door.
  3. Mark each end of the crack with a pencil line and the date, so you can see whether it grows.
  4. Measure the width at the widest point and write it down.

Do not fill or paint over it yet. InterNACHI notes a clean, fresh-looking crack suggests recent movement, while a dirty or previously filled crack may be inactive.[1] Filling it first erases that clue.

Day 1 to 3: look around it

  • Is it one crack or a pattern? Look for matching cracks on the other side of the wall, in the corners of doors and windows, and in brick outside.
  • Do any doors or windows stick or no longer latch? Does a floor slope? See signs of foundation problems.
  • Is there water: damp patches, stains, white mineral deposits, a musty smell?
  • What does the crack look like? Fine, shrinking cracks in new concrete are common. The concrete industry's technical sheet says some cracking is normal and not necessarily a sign of poor materials, workmanship or a structural problem.[2]

The direction matters too. InterNACHI describes horizontal or sweeping cracks in a foundation wall as potentially serious.[1] See foundation crack types for how to read the pattern.

The weeks after: watch it

  • Recheck the pencil marks and the width every couple of weeks, and again after wet and dry spells.
  • InterNACHI notes cyclical movement can take six months or more to measure, so a short watch tells you little about seasonal cracks.[1]
  • Fix obvious water problems in the meantime: gutters, downspouts and grading; see water and drainage.

When a crack is a reason to get an evaluation

A crack that keeps growing, a pattern across several parts of the house, or a crack paired with sloping floors and sticking doors is worth a structural engineer's evaluation before you ask anyone for a repair quote. See do you need a structural engineer?

Common questions

Should I seal a crack right away?

Wait, and document first. Sealing does not address why the crack formed, and a filled crack is harder to read later.[1] The concrete industry advises finding the cause before repairing and checking drainage when a crack leaks.[2]

Foundation Crack Types: Vertical, Diagonal, Horizontal and Stair-StepHow to read common crack patterns, which are usually minor, and which call for an engineer.Signs of Foundation Problems: What to Look For Inside, Outside and BelowA room-by-room and outside checklist of the signs that suggest foundation movement, and what does not.Is It Normal Settling? How to Tell Settling From a Foundation ProblemWhat normal settling looks like, what does not, and how to track it before deciding.Do You Need a Structural Engineer for Foundation Repair?When an independent engineer is worth hiring, what they evaluate, and how it differs from a contractor's inspection.

References

Figures and claims marked with a number come from these references. Dates are the publication or last-update dates shown by the publisher, where one was shown. Older references are flagged in the text.

  1. Inspecting Foundation Walls and Piers. InterNACHI (International Association of Certified Home Inspectors), revised January 2013.Inspector-training material. It describes cracks by cause rather than by a fixed vertical/diagonal/horizontal chart.
  2. CIP 7: Cracks in Residential Basement Walls. National Ready Mixed Concrete Association (NRMCA); copyright years 1979, 2000 and 2014 shown, with 2014 the most recent.Industry trade association for concrete producers. Focuses on poured-concrete basement walls.
  3. Guidelines for the Evaluation and Repair of Residential Foundations, Version 1. Texas Section, American Society of Civil Engineers; adopted October 3, 2002, effective January 1, 2003.Written for Texas conditions and by its own terms not a standard of care. Widely used as a reference for slab and pier-and-beam evaluation. Published in 2002.

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