How is a settled foundation lifted, and what happens after?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: Lifting raises the settled parts of a foundation back toward their original height using the piers that now support it. Because no foundation is built perfectly level ¹, the target is the best practical lift the structure will tolerate, not a flat floor. A lift is followed by plumbing checks, a new elevation survey and a written record of every pier ¹².

What does "lifting" mean?

Once piers are installed under a settled section, hydraulic jacks set on the pier brackets push the foundation up. A pier is a steel or concrete column driven or drilled down to firmer soil or rock so the house no longer rests only on the shallow clay. On Oklahoma steel push pier jobs, each pier is first driven until it reaches at least 6,000 psi of hydraulic pressure, and a large Tulsa job logged a median of about 9,000 psi ². Those same records keep shims, the steel spacers between the bracket and the pipe, to no more than three per pier ².

Lifting is only appropriate where the foundation has actually settled (dropped). If part of the house has heaved (risen because clay swelled), raising the low areas up to the high spot spreads damage instead of fixing it. See heave vs settlement before any lift is planned.

Why is "level" not the goal?

Forensic engineers note that foundations are not constructed perfectly level, so a survey reflects as-built variation plus movement since construction ¹. Engineers evaluate a foundation by tilt (an overall slope across the whole foundation) and deflection (how far the surface bows away from a straight line between two points), together with visible distress, rather than by one high-to-low number ¹. See tolerances and standards.

During a lift, crews watch for signs that the structure is resisting:

• cracks closing (expected) versus new cracks opening
• doors and windows changing how they fit
• the foundation binding or "fighting" in one area

When those signs appear, lifting stops. The final height is whatever the house allows without new harm.

What checks follow the lift?

Expansive-soil guidance from forensic engineers recommends three steps after any lifting or lowering ¹:

1. Plumbing tests to find leaks that the movement may have caused, especially in drain lines under the slab.
2. Repair of any leaks found, since a leak under a slab can cause new movement.
3. A new baseline elevation survey, so later movement can be measured against a known starting point.

The model plumbing code also limits lifting: a slab and its plumbing may not be lifted together to create a void underneath unless the space below is a crawl space with inspection access ¹. More on testing: plumbing leaks under slab.

Which records matter later?

Each pier's depth, final pressure and final elevation are recorded on Oklahoma installation logs ². These records serve several later uses:

Oklahoma's seller disclosure form asks directly, "Are you aware of any previous foundation repairs?" and separately asks about warranties covering the foundation ⁴. Mortgage rules also matter: when an appraisal shows abnormal settlement, the lender must show the condition was corrected or provide a professionally prepared report that it poses no threat of structural damage ⁵.

If an engineer is involved, only that licensed engineer can issue an engineering completion letter. Oklahoma's engineering board allows a repair company to send its own completion letter, but not to call it an engineering completion letter ³. See working with engineers.

What restoration work follows?

After the structure stops moving, cosmetic work can follow: brick mortar repair (tuckpointing), drywall patching, and door and trim adjustment. Doing this work before the house has settled into its new position risks re-cracking. A monitoring program with repeat surveys shows whether movement has stopped.

Related

• Steel push piers
• Elevation surveys
• Heave vs settlement
• Over-lift heave after a drought lift
• Contracts, warranties and liens
• Cosmetic repair only