When a Central Florida house settles or a sinkhole investigation finds trouble below the slab, the repair proposal usually names one of three approaches, or a mix of them: compaction grouting, chemical grouting and underpinning with steel piers. Florida law groups two of them together. The sinkhole statute describes "underpinning or grouting or any other repair technique performed below the existing foundation" (Fla. Stat. §627.707(5)(a)). Here is how each works in general terms, how the choice is made and what to ask.
We connect Orlando-area homeowners with independent Florida-licensed contractors for free, no-obligation foundation repair quotes. The contractor you choose quotes, contracts and does the work.
Start with the cause, not the method
Orlando-area soils are mostly sands with negligible shrink-swell, according to USDA NRCS soil survey data, so clay heave is rarely the story here. The usual settlement drivers in the research are organic (muck) layers that compress, poorly compacted fill, erosion and washout at slab edges, and karst raveling. Florida's statute defines "sinkhole activity" as settlement that results "from contemporaneous movement or raveling of soils" into "subterranean voids created by the effect of water on a limestone or similar rock formation" (§627.706(2)(i)).
The Florida Geological Survey (FGS) adds a caution: many reported depressions have other causes, including "organic layers which compress as water is removed, collapsed or broken sewer and drain pipes or broken septic tanks, improperly compacted soil after excavation work, and even buried trash, logs and other debris." A method that suits voids in limestone may not suit a leaking drain line, which is why diagnosis comes first. Our guide to settlement versus sinkholes covers the difference, and Orlando's soils are explained in a separate post.
Compaction grouting in general terms
Compaction grouting, sometimes called cement grouting, places a cement-based grout into the ground below and around the house. It is one of the "below the existing foundation" techniques the statute refers to. The target is the soil the house rests on, not the house itself: the aim is to treat the ground that moved so the structure above has a more stable base. It is the "grouting" in the Florida Senate's 2010 cost comparison below.
Injection depth, spacing and grout volume are set by the engineer's design for each site. No reliable published per-hole or per-cubic-yard price was found, so confirm any such figure in a written quote.
Chemical grouting in general terms
Chemical grouting uses a chemical or polyurethane grout instead of a cement mix. A related, shallower job is polyurethane foam lifting of a slab, where foam is injected under concrete to raise it. National cost guides put polyurethane lifting at about $5 to $25 per square foot, with a minimum job of roughly $300 to $700 (Angi and HomeGuide, 2026, as search summaries; estimates, not quotes).
Lifting a slab and stabilizing deeper soil are different goals, and the engineer's report says which one the house needs.
Underpinning with steel piers in general terms
Underpinning transfers the load of the house through steel elements to deeper, firmer bearing. The two common types are steel push piers, driven to refusal, and helical piers. On Florida sinkhole work the method is usually described as steel underpinning to limestone.
How deep piers go varies from house to house. FGS staff, quoted in a Florida Senate report, describe a setting of shallow limestone "overlain by sands with various mixtures of clay" in Orange County and parts of Lake and Seminole counties. No Orange County depth-to-limestone figure was found, so depth is something to ask about in every quote. National guides list steel or push piers at about $1,000 to $3,000 each installed and helical piers at about $2,000 to $4,000 each (This Old House, Bob Vila, HomeGuide; estimates, not quotes). See house leveling and piers for more.
When an engineer typically chooses each
Choosing a method is engineering. Florida defines engineering to include "investigation, evaluation, planning, and design" of structures (§471.005), and only a Florida-licensed professional engineer (PE) may practice it. A contractor may install a repair a PE designed (§471.003(2)(f)).
There is no simple rule of "grout here, piers there". What the decision rests on:
- What testing found. A PE or professional geologist investigation can include floor-elevation surveys, ground-penetrating radar and standard penetration test borings. Insurers must use a PE or professional geologist to test when a sinkhole loss is suspected (§627.7072).
- Where the weak layer is. Shallow loss of support under a slab, organic compression, fill problems and voids in deeper sediments call for different designs.
- The cover over the limestone. The 1985 state sinkhole-type map (Map Series 110) describes areas where cover is "mainly of incohesive and permeable sand" and sinkholes "develop gradually", and areas of "cohesive clayey sediments" where they "develop abruptly". Its scale is regional, so it informs, not decides, a design.
Florida's neutral evaluation process for disputed sinkhole losses must address "All methods of stabilization and repair both above and below ground" (§627.7074), which shows that more than one approach is normally on the table.
Grouting vs underpinning cost: the 2010 Senate figures
In its December 2010 Interim Report 2011-104, the Florida Senate wrote that, according to geologists and engineers, stabilizing an average $150,000 home would cost about $75,000 by grouting or about $35,000 by underpinning; for an average $300,000 home, grouting was estimated at $90,000 and underpinning at $45,000. These are 2010 dollars and historic estimates, not current prices.
A more recent national figure from Angi puts typical residential sinkhole repair at $10,000 to $20,000 in most cases (2026, search summary). Current jobs are priced from a PE's design for the specific house. Our foundation repair cost guide lists the other ranges.
The insurer's engineer rule, as information
When a repair is paid under a sinkhole loss policy, Florida law sets the method. The insurer "shall pay to stabilize the land and building and repair the foundation in accordance with the recommendations of the professional engineer", and the policyholder "must repair such damage or loss in accordance with the insurer's professional engineer's recommended repairs" (§627.707(5)). The insurer may limit payment to actual cash value, which "does not include underpinning or grouting", until the policyholder contracts for the stabilization (§627.707(5)(a)). The statute also sets a 90-day window to sign the repair contract and a 12-month completion target, with exceptions. Neutral evaluation is available under §627.7074.
Ask your insurer what your policy covers. This is general information, not legal or insurance advice. Our post on Florida sinkhole insurance law quotes more of the statute.
Questions to ask before you sign
- What is your Florida license number? Look it up on MyFloridaLicense.com. A county business tax receipt is not a license.
- Who designed this repair, and will the plans be signed and sealed by a Florida PE? Orange County requires sealed plans when repairs affect structural stability.
- Which method is proposed, and what did testing find that points to it?
- What depth or grout volume does the price assume, and how is extra depth or volume priced?
- Who pulls the permit, and is a Notice of Commencement needed? See our Orange County permit guide.
- Will a PE monitor the work and issue a completion report? For insured sinkhole repairs, the statute requires one (§627.7073(3)).
- What warranty does the contractor offer, in writing, and is it transferable?
If you want to compare written proposals, you can request free quotes, or read about sinkhole and subsidence repair and inspections and engineer reports.
Frequently asked questions
Is compaction grouting better than piers?
Neither is better in every case. Grouting treats the soil below and around the house, while piers carry the house's load down to deeper bearing. Which fits depends on what testing finds, where the weak layer is and how deep firm ground lies. A Florida-licensed professional engineer makes that call, and for insured sinkhole repairs the insurer's engineer's recommendation governs under section 627.707(5).
How much does sinkhole grouting cost in Florida?
The most-cited Florida figures are from December 2010: the Florida Senate reported engineers' and geologists' estimates of about $75,000 to grout an average $150,000 home and about $35,000 to underpin it. Those are 2010 dollars. Angi's 2026 range for typical residential sinkhole repair is $10,000 to $20,000 in most cases. Current prices come from a written quote based on a PE's design.
Can a contractor decide which method to use?
A contractor can recommend and install a method, but diagnosing the cause and designing a structural repair is engineering under Florida law, which only a licensed professional engineer may practice. A contractor may build a repair a PE designed. Ask whether the proposal is based on a PE's report and whether the plans will be signed and sealed for the permit.