Signs of foundation problems, and when to worry
Almost every house in San Antonio has a few cracks. The clay under much of the city swells and shrinks with the weather, and houses move a little with it. What matters is whether the house is moving enough to need repair. One sign on its own is rarely conclusive. Several signs together, or one that keeps getting worse, is the time to have someone look.
Signs worth checking
Stair-step cracks in brick
Cracks that follow the mortar joints diagonally, often near a corner of the house.
Doors that stick or swing open
The frame has gone out of square as one side of the house moves.
Cracks at door and window corners
Diagonal cracks in sheetrock running out from the corners.
Sloping floors
A marble rolls one way on a slab, or a pier and beam floor feels soft or bouncy.
Gaps at trim and cabinets
Gaps open between trim and walls, around cabinets, or where a chimney meets the house.
Cracked tile or slab
Especially a crack where one side now sits higher than the other.
Windows that no longer open or close as easily as they used to are another sign of the same movement.
Cracks that are usually cosmetic
Thin, straight hairline cracks in drywall or in a garage slab, which do not change over months, are common in houses that are otherwise fine. Concrete shrinks as it cures, and a new house settles in its first few years.
| Usually cosmetic | Worth an inspection |
|---|---|
| Thin, straight hairline crack in drywall | Diagonal crack running from a door or window corner |
| Hairline crack in a garage slab that has not changed in months | Crack where one side now sits higher than the other |
| Small cracks in a new house in its first few years | Any crack that keeps getting wider |
| One crack on its own | Cracks together with sticking doors or sloping floors |
How to tell whether it is getting worse
Mark both ends of a crack with a pencil line and the date, and photograph it next to a ruler. Check the same cracks every month or two, and again after long dry spells or heavy rain. Note which doors stick, and in which season.
A record like this is also useful to an inspector, and to an insurer if a plumbing leak turns out to be the cause.
When to book an inspection
- A crack is widening, or the two sides no longer line up.
- Several of the signs above appear at the same time.
- You are buying or selling a house.
- You suspect a plumbing leak under the slab, such as an unexplained jump in your water bill.
Most repair companies inspect for free. For a neutral opinion, a structural engineer's report is the better choice; see our guide to foundation inspections in San Antonio. Keeping the soil evenly moist helps prevent movement, within SAWS watering rules.
Seeing several of these signs? Compare the ten most-reviewed foundation repair companies in San Antonio and send an enquiry.
See the top 10 companiesCommon questions
When should I worry about foundation cracks?
When a crack is getting wider, when one side has dropped below the other, or when cracks appear together with sticking doors or sloping floors.
Are hairline cracks in a foundation normal?
Thin, straight hairline cracks that do not change over months are common and usually cosmetic, especially in newer houses as concrete cures.
What are the first signs of foundation problems?
Doors that start sticking, diagonal cracks at the corners of doors and windows, and stair-step cracks in brick are often the first things homeowners notice.