Most foundation cracks in Chula Vista fall into one of three groups: cracks from concrete shrinking as it cured, cracks from clay swelling or shrinking under the house, and cracks from soil settling. Each needs a different repair. Chula Vista Structural figures out which group your crack belongs to, then repairs it in a way that fits the cause. If the crack points to a bigger structural issue, we coordinate with licensed engineers as needed.
Three kinds of cracks, three kinds of fixes
Shrinkage cracks
Concrete loses water as it cures and gets slightly smaller. That creates thin cracks, usually straight or gently wandering, often in garage slabs and along stem walls. They tend to show up in the first year or two and then stay the same.
Typical fix: often nothing structural. If water or bugs get in, a sealant or a simple injection works. We still check that the crack is not getting wider.
Clay heave and shrink cracks
In eastern Chula Vista, the Otay Formation contains bentonite clay that swells when wet and shrinks when dry (California Geological Survey). When the soil under part of a slab moves, the slab bends. Cracks from this often run diagonally from corners, may be wider at one end, and can open and close with the seasons. Drywall and stucco cracks usually show up with them.
Typical fix: moisture control first, meaning drainage, downspouts, and irrigation. Then crack repair once the movement has calmed down. Sealing a clay crack in the dry season, without fixing the water problem, often means it reopens in winter. See expansive clay.
Settlement cracks
When soil under part of the house compresses, that part drops. Settlement cracks often have vertical offset, where one side sits lower, or form a stair-step pattern in block walls. In Chula Vista, we look closely at homes near canyon edges, where fill was placed, and near the Sweetwater River, Otay River, and Telegraph Canyon Channel, where the City’s hazard plan identifies alluvial soils.
Typical fix: stop the settlement, then repair the crack. That can mean underpinning or other support. See foundation settlement repair.
A special case: post-tension slabs
Many newer east-side homes have post-tension slabs with tightened steel tendons inside. The tension helps keep cracks closed, so a PT slab crack that has opened wide deserves attention. More important, nobody should drill into a PT slab for injection ports or anchors without first locating the tendons. We plan any PT crack repair around the tendon layout, with engineering input when needed. See post-tension slab problems.
How we read a crack
We look at:
- Width. Measured, not guessed. We may put a gauge across it to track changes.
- Direction. Vertical, horizontal, diagonal, or stair-step.
- Offset. Is one side higher or pushed out?
- Location. Corner, mid-wall, near a slope, near a downspout.
- Other symptoms nearby. Sticking doors, sloping floors, drywall cracks in the same area.
- Timing. When it appeared and whether it changes with rain or summer.
One crack alone tells us little. A crack with sticking doors and a sloping floor nearby tells us a lot more.
Crack repair methods
- Epoxy injection. Bonds the concrete back together across a stable crack. Good for structural cracks after the cause is fixed.
- Polyurethane injection. Flexible and water-blocking. Good for leaking cracks where some movement may continue.
- Routing and sealing. For surface cracks in slabs that just need to be closed off.
- Stitching or reinforcing. For cracks that need added strength across them.
- Section repair. Removing and replacing a damaged piece of footing or slab.
We pick the method after we understand the cause. A crack that is still moving will break through a rigid epoxy fix.
When a crack is urgent
Most cracks are not emergencies. Call soon if you see:
- A crack that grew noticeably in weeks or months
- Horizontal cracks in a wall that holds back soil
- Offset of more than a small amount between the two sides
- Doors or windows that suddenly stopped working
- New cracks after a leak, a storm, or nearby digging
Permits
Cosmetic sealing usually does not need a permit. Structural crack repair, footing work, or underpinning generally does. The City of Chula Vista says most repairs or alterations require a building permit. We tell you which applies before we start.
Crack repair questions
What do I need to do before the crack repair?
Clear a few feet on each side of the crack, inside and outside, and move anything stored against that wall. If the crack is in the garage, plan to park outside that day. Tell us about any recent leaks or plumbing work, since that can change the order of the job.
Can I just fill it with caulk?
For a hairline shrinkage crack, caulk keeps water out. For a moving crack, caulk hides the symptom and makes it harder to track.
Will the crack come back?
If the cause is fixed and the repair fits the crack type, usually not. If clay or settlement is still active, it may.
Talk to us about a crack
Send us a photo with something for scale, tell us where it is, and we will set up a visit.
Sources for local facts
- California Geological Survey, San Diego 30’×60’ Quadrangle pamphlet (Otay Formation bentonite)
- County of San Diego 2023 Hazard Mitigation Plan, City of Chula Vista Annex (canyons, alluvial areas)
- City of Chula Vista Development Services permits page