Signs of foundation problems
A crack over the door. A door that suddenly will not close. Floors that slope enough to roll a marble. These are the signs of foundation problems that send people looking for foundation repair, and they deserve a careful look, not panic. Every house moves a little, and not every crack means trouble. Here is what experienced pros look for.
- Diagonal cracks running from the corners of doors and windows in drywall
- Doors that stick, swing on their own, or show an uneven gap at the top
- Windows that bind, or gaps opening between window frames and the brick
- Stair-step cracks in brick or block, or mortar cracks that keep growing
- Sloping, bouncy or uneven floors, and cracked floor tile
- Gaps between baseboards and the floor, or where walls meet the ceiling
- A chimney, porch or garage pulling away from the house
Hairline cracks vs. wide cracks
| Foundation cracks | What they often mean |
|---|---|
| A thin hairline crack, even on both sides | Usually shrinkage as the concrete or drywall dried. Mark it and watch it. |
| A crack wider at one end than the other | Often movement. Have it checked. |
| Stair-step cracks in brick or block | Often settling or heaving under that part of the house. |
| One side higher than the other, or a crack that keeps growing | Have it inspected soon. |
Why clay soil moves
Many homes sit on expansive clay. It swells when it gets wet and shrinks when it dries, and the foundation moves with it. The real trouble is uneven moisture: one side of the house stays wet from a downspout or a leak, while another dries out in the sun or next to a thirsty tree. That uneven push and pull lifts some parts of the house and lets others drop.
- Long dry spells open gaps between the soil and the edge of the foundation.
- Large trees close to the house pull water from the soil under it.
- A plumbing leak under a slab can soak the soil in one spot.
Four foundation types compared
| Type and how it is built | Common problems | Typical repairs |
|---|---|---|
| Slab-on-grade. A concrete slab poured on the ground, with thicker beams around the edge and under main walls, reinforced with steel. | Edges or corners dropping or heaving with soil moisture, cracks, and plumbing leaks under the slab. | Pressed concrete piles or steel piers under the beams, plus drainage and moisture control. |
| Pier and beam. The house rests on wood beams that sit on concrete piers, with a crawl space underneath. | Sinking or shifting piers, rotted or overloaded beams, sagging or bouncy floors, a damp crawl space. | Shimming and re-leveling, added or replaced piers, new beams or sills, better airflow and drainage. |
| Crawl space with block stem walls. A footing with concrete block walls around the edge, often with piers inside. | Stair-step cracks in the block, settling footings, leaning walls, moisture. | Piers under the footing, rebuilt or reinforced wall sections, a vapor barrier and drainage. |
| Basement. Poured concrete or block walls below ground, on footings. | Leaks and seepage, cracks, walls bowing inward from soil pressure, settling. | Crack injection, wall bracing or anchors, drainage and waterproofing, piers under the footings. |
Foundation repair methods in plain words
- Pressed concrete piles: short concrete cylinders stacked and pressed into the ground with a hydraulic jack under the foundation until they will not go any further. The house is then lifted and set on them with shims. Common under slabs in clay soil areas.
- Steel push piers: sections of steel pipe driven down with hydraulic rams that push against the weight of the house, until they reach firm soil or rock. A steel bracket ties each pier to the footing.
- Helical piers: steel shafts with screw-like plates, turned into the ground until they reach a measured resistance. They suit lighter loads such as porches and additions, and can carry weight right away.
- Shimming and re-leveling pier and beam: jacking the beams up, adding steel shims or new pier caps, adding piers where beams span too far, and replacing rotted wood.
- Slab jacking (mudjacking or poly foam): drilling small holes and pumping a cement slurry or expanding foam under a sunken slab to lift it. It suits driveways, sidewalks, patios and garage floors; it does not stop deep soil movement under a house.
- Crack sealing and wall bracing for basements: injecting cracks with epoxy to bond them or with polyurethane to stop water, and bracing bowing walls with steel beams, wall anchors or carbon fiber straps.
- Drainage and moisture control: gutters with downspouts carried well away, soil sloped away from the house, and drains where water collects. In clay soils, keep the moisture around the foundation steady during long dry spells, following local watering rules. Root barriers can help near large trees.
Get an independent engineer's report first
Before you choose a repair plan, consider hiring an independent structural engineer, one who does not sell repairs. The engineer measures floor levels, looks at the cracks, the soil, the drainage and signs of leaks, and writes a report: what is moving, why, and what repair makes sense. Then every pro bids on the same plan, so the bids are easy to compare.
- Check the engineer's license with your state.
- Ask whether they will check the finished work and write a final letter. A letter like that helps when you sell the house.
- A repair company's own inspection can still be useful, but it is also a sales visit, so weigh it against an independent report.
What a foundation repair bid should list
- The number of piers and a drawing showing where each one goes
- The type of pier, and how the depth is decided for each one
- Whether the plan is to lift the house or to hold it where it is
- On slab homes, a plumbing test before and after, since lifting can crack drain lines, and what happens if a leak is found
- Permits and inspections, and who pulls them
- Breaking and patching concrete, any tunneling, and landscaping restoration: plants moved and replanted, soil backfilled and packed, cleanup
- The warranty terms in writing: what it covers, for how long, and whether it transfers to the next owner
- Whether an engineer's letter is included, the start date, the timeline and the payment schedule
Cosmetic fixes after a lift, such as drywall cracks and doors that need adjusting, are usually separate, so ask.
Questions to ask a foundation pro
- What do you think is causing the movement, and how does your plan address it?
- How did you decide the number and placement of piers?
- How do you know when each pier is deep enough?
- What will you do about drainage and moisture around the house?
- Will your own crew do the work?
- Can I read the warranty, and does it transfer?
- Can you show proof of insurance and any license my city or state requires?
Be careful with pressure to sign the same day or with scare talk that the house is about to fail. A sound repair plan will still be sound next week. For more, see how to choose a contractor.
Get foundation repair bids on BidHandyman
Take photos of the cracks, the sticking doors and the outside walls, mention the foundation type if you know it, and describe any engineer's report, then post it free. Verified local foundation pros can inspect it and bid, and you compare, message and hire the one you like, with no obligation. Post your foundation repair. Sunken driveway or walkway too? See concrete driveway replacement.