# When to Worry About Foundation Cracks (Width Guide) | Foundation Repair Baton Rouge > Under 1/8 inch: usually cosmetic. 1/8–1/4 inch: watch it. Over 1/4 inch, growing or offset: get it evaluated. A crack width guide for Baton Rouge homes. URL: https://foundationrepairbatonrougelouisiana.com/guide/how-big-is-too-big-foundation-crack/ Learn·Warning signs # How Big Is Too Big for a Foundation Crack? A practical crack-width guide, what direction and offset tell you, and how to monitor a crack before you pay for anything. By Foundation Repair Baton Rouge · Published September 22, 2026 · Updated September 22, 2026 **As a rule of thumb, cracks under 1/8 inch are usually cosmetic, 1/8 to 1/4 inch are worth monitoring, and anything over 1/4 inch — or any crack that is growing or offset — should be evaluated.** Width matters, but growth, offset and whether doors and floors are affected matter more. [Foundation Repair Baton Rouge](https://foundationrepairbatonrougelouisiana.com/) measures cracks on every evaluation. Here’s the framework we use. ## Crack width guide Width What it usually means What to do Hairline to 1/16 in Concrete shrinkage or minor seasonal movement Note it; usually no action 1/16 to 1/8 in Minor movement Mark and monitor 1/8 to 1/4 in Moderate movement Monitor closely; evaluate if growing Over 1/4 in Significant movement Get it evaluated Any width with offset One side has moved relative to the other Get it evaluated These are general guidelines used widely in the industry, not code limits; context matters. ## Direction tells you more than width - **Diagonal cracks from door and window corners** — differential settlement. - **Stair-step cracks in brick** — the beam under that wall is dropping. - **Vertical cracks in a slab or stem wall** — often shrinkage; check for offset. - **Cracks aligned across the slab, driveway and street** — in a few Baton Rouge neighborhoods, a possible fault signature. See the [Baton Rouge fault guide](https://foundationrepairbatonrougelouisiana.com/guide/baton-rouge-fault-foundation-damage/). Have a crack you're not sure about? Free laser survey and a written per-piling price. [(225) 635-8757](tel:+12256358757) ## How to monitor a crack 1. Measure the width at its widest point and write it down with the date. 2. Pencil a line across each end of the crack with the date. 3. Photograph it with a ruler for scale. 4. Re-check every month or two through a wet season and a dry one. Growth past your pencil marks, or width changes of more than a hairline, mean the crack is active. We also install calibrated crack monitors that read to fractions of a millimeter. ## When sealing is the right fix Stable cosmetic cracks can be sealed to keep moisture and insects out. Cracks from active settlement shouldn’t be sealed until the settlement is fixed — the patch just cracks again. See [foundation crack repair](https://foundationrepairbatonrougelouisiana.com/foundation-crack-repair/). ## Bottom line Under 1/8 inch and stable: watch it. Over 1/4 inch, growing or offset: get it measured. For a free evaluation, call Foundation Repair Baton Rouge. Questions about your house? Call Foundation Repair Baton Rouge. [(225) 635-8757](tel:+12256358757) ## Quick answers ### Should I worry about foundation cracks? Worry about cracks that are wider than about 1/4 inch, growing, offset (one side higher), or accompanied by sticking doors and sloping floors. Fine, stable hairline cracks are common and usually cosmetic. ### Are horizontal or vertical cracks worse? In slab homes, vertical and diagonal cracks are most common. Diagonal cracks from the corners of openings and stair-step brick cracks point to differential settlement. Horizontal cracks in walls can indicate lateral pressure and should be evaluated. ### Can I seal a foundation crack myself? You can seal a stable, cosmetic crack to keep moisture out. Don't seal a crack you're monitoring — you'll hide whether it's growing. [ Related service Foundation Crack Repair Measuring, mapping and sealing slab and stem-wall cracks — after we confirm whether the ground under them is still moving. $400–$1,500 per crack (cosmetic) See the service](https://foundationrepairbatonrougelouisiana.com/foundation-crack-repair/) Get a Free Quote Free on-site evaluation · written price More guides - [Is the Baton Rouge Fault Damaging My Foundation?](https://foundationrepairbatonrougelouisiana.com/guide/baton-rouge-fault-foundation-damage/) - [House Settling vs Foundation Problems — How to Tell the Difference](https://foundationrepairbatonrougelouisiana.com/guide/house-settling-vs-foundation-problems/) - [9 Signs of Foundation Problems in Baton Rouge Homes](https://foundationrepairbatonrougelouisiana.com/guide/signs-of-foundation-problems/) - [What Is the Best Time of Year for Foundation Repair in Louisiana?](https://foundationrepairbatonrougelouisiana.com/guide/best-time-of-year-for-foundation-repair/) - [Can You Live in Your House During Foundation Repair?](https://foundationrepairbatonrougelouisiana.com/guide/can-you-live-in-your-house-during-foundation-repair/) [All guides](https://foundationrepairbatonrougelouisiana.com/guide/) [Foundation Repair Baton Rouge Stop guessing at the number Book a free evaluation and get a written, per-piling price for your house. (225) 635-8757](tel:+12256358757) Book your free foundation evaluation Start with clear answers from an experienced team. Tell us what you are seeing, and we will call back the same business day to arrange your free evaluation. Faster by phone: [(225) 635-8757](tel:+12256358757)