House leveling brings floors back toward level when the framing or supports under them have dropped. Sometimes the fix is above the foundation, in joists and beams. Sometimes it's below, in the footings or soil. HomeGuide stresses fixing the underlying cause rather than covering it up, and suggests a foundation inspection first [1].
Where the sag is coming from
- Framing. Joists that are undersized, cracked or damaged by rot or insects [1].
- Supports. Joists or beams carrying too long a span, which Foundation Supportworks names as a cause of floor bounce [2].
- Foundation. A settling footing under part of the house, which may call for push piers or helical piers.
Foundation Supportworks markets its SmartJack crawl space supports for stabilizing beams and joists, lifting floors back toward their original position, and reducing floor bounce from weak joists or long spans [2].
Common repairs and national prices
| Repair | Published range | Source |
|---|---|---|
| Surface-level unevenness | $300 to $2,000 | HomeGuide, Feb 2026 [1] |
| Sistering a joist | $150 to $325 per joist | HomeGuide, Feb 2026 [1] |
| Replacing a damaged joist | $350 to $1,000 per joist | HomeGuide, Feb 2026 [1] |
| New posts or a beam | $1,000 to $5,000 | HomeGuide, Apr 2026 [3] |
| Major joist or support work | $4,500 and up, past $20,000 | HomeGuide, Feb 2026 [1] |
| House lifting | $20,000 to $30,000 | Fixr, Jan 2026 [4] |
HomeGuide's own guide gives the structural range two ways, $4,500 and $5,000 at the low end [1]. All figures are national.
Questions for the contractor
- Is the sag in the framing, the supports or the foundation?
- How much lift are you planning, and over how long?
- Will lifting crack drywall or stick doors upstairs, and who fixes that?
- Does the plan need a permit? Elm Grove lists structural beam or column work as needing one [5], and Mequon's list includes structural changes [6].
FAQ
Will the floor go back to perfectly flat?
Get the target in writing. The quote should say how much lift is planned and how it will be checked.
Do I need an engineer?
It depends on the job and the town. Franklin, for one, asks for the size of reinforcement beams on foundation permits [7].
Is this the same as foundation repair?
Only when the foundation is the cause. That's why HomeGuide recommends an inspection first [1]. See foundation inspection.
Get a quote
Request a quote and note which rooms feel sloped or bouncy.
We're a referral service, not a contractor, and independent contractors may pay us for referrals.
Sources
- HomeGuide, "Sagging Floor Repair Cost," Feb 6, 2026. Supports: fix underlying problem; schedule a foundation inspection; joists undersized or damaged by rot or insects; surface $300 to $2,000; sistering $150 to $325; replacing joists $350 to $1,000; structural $4,500 to $20,000+ (also stated as $5,000 to $20,000+). https://homeguide.com/costs/sagging-floor-repair-cost
- Foundation Supportworks (manufacturer), Solutions: SmartJack. Supports: stabilizes crawl space beams and joists; lifts floors toward original position; reduces bounce. https://www.foundationsupportworks.com/solutions.html
- HomeGuide, "Floor Joist Repair Cost," Apr 20, 2026. Supports: adding support posts or beams $1,000 to $5,000. https://homeguide.com/costs/floor-joist-repair-cost
- Fixr, "How Much Does It Cost to Repair a Foundation in 2026?," updated Jan 27, 2026. Supports: house lifting $20,000 to $30,000. https://www.fixr.com/costs/repair-foundation
- Village of Elm Grove, Alterations. Supports: structural beam or column installation/removal requires a permit. https://www.elmgrovewi.org/822/Alterations-Remodels
- City of Mequon, Building Permit Information, Residential. Supports: permit list includes structural changes and foundation repair. https://www.cityofmequonwi.gov/commdev/page/building-permit-information-residential
- City of Franklin, Foundation Repair Memo (PDF). Supports: size of reinforcement beams. https://www.franklinwi.gov/Files/Inspection/foundationrepairmemoR2017.pdf