What underpinning is
Underpinning stabilizes a footing that has settled, either by pushing or screwing supports down to firmer soil or by extending the footing deeper.
Piering estimates, per pier and per job
Our estimate for a pier is $1,000 to $2,175 per pier, installed, a model and not a quote, built from two national published ranges and adjusted for California wages. The table also carries a range for a whole underpinning job. Cement mason pay appears below, which is what workers earn and not what a pier costs you.
| Item | Figure | What it is |
|---|---|---|
| Estimated range, not a quote | $1,000 to $2,175 per pier, installed | Built from 2 national published ranges, adjusted by the California cement mason wage ratio (1.18). Two California foundation companies publish prices (Quartz Construction in San Jose, a range table; Avalon Structural near San Jose, inspection fees); that is too few to anchor a California range, so no company price moves the estimate. Basis: no state company sample (no counted California company price for this job), national estimate only. |
| Estimated range per underpinning job, not a quote | $10,000 to $40,700 per underpinning job | Built from one national published range, adjusted by the California cement mason wage ratio (1.18). Two California foundation companies publish prices (Quartz Construction in San Jose, a range table; Avalon Structural near San Jose, inspection fees); that is too few to anchor a California range, so no company price moves the estimate. Basis: no state company sample (no counted California company price for this job), national estimate only. |
| Cement masons and concrete finishers, California mean | $34.09 an hour | Average hourly wage in California for this occupation (BLS, May 2025). It's pay, so it won't appear on your bill. |
| Cement masons and concrete finishers, United States mean | $28.87 an hour | Nationwide average from the same BLS survey; the gap between the two sets the wage adjustment. |
Estimated range. Built from national published ranges (2 sources), adjusted by California's cement mason wage ratio to the US (1.18, BLS May 2025). Not a quote. Only two of the 18 California foundation companies we looked at publish a price we could count, so no company price anchors the estimates. We have no counted California company price for this job, so the range is our national estimate alone. Full method. Prices as of Oct 23, 2026.
Soil zones and soil reports
In the liquefaction and landslide zones the state geologist maps, cities and counties must use the zones in permitting, and the California Geological Survey says the stability of foundation soils must be investigated there. For subdivisions, H&SC 17955 makes the approved soil recommendation a condition of the building permit. Whether a single-house pier job triggers a soil investigation is for the city to say.
Which CSLB license to look for on a pier quote
CSLB's C-61 limited specialty list includes D-30, titled Pile Driving and Pressure Foundation Jacking. A B general building contractor may also take the job when it spans two or more unrelated trades. Once the job is $1,000 or more, or involves a permit or hired workers, the B&P 7048 exemption is gone and the contractor must hold a CSLB license.
Ask which class it holds. Check the number on CSLB's Check a License page, and put the payment schedule in the contract, because B&P 7159.5 bars a contractor from asking for more than the value of work done, apart from a down payment of $1,000 or 10 percent, whichever is less.
Get an independent read before you agree to a pier count
The company that diagnoses the settlement often sells the piers. Ask for a written assessment from someone who won't install anything, then compare each quote's pier locations and spacing against it.
If a quote's reasoning rests on soil, ask whether a soil investigation was done and who signed it. The USDA Web Soil Survey and the EQ Zapp map give a first look at an address, and neither replaces a site investigation.
Digging notices and city permits
Gov. Code 4216.2 asks an excavator to notify the regional notification center at least two working days and not more than 14 calendar days before excavating, except in an emergency. Inside 24 inches of a marked line the digging is by hand tool. USA North 811 covers 49 northern and central counties, including Alameda, Fresno, Sacramento and Santa Clara, and DigAlert covers southern California, including Los Angeles, Orange and San Diego. Utilities mark only their own lines, not private ones, so ask the pier contractor who calls and when.
The permit comes from the building department, which decides whether piering needs one and whether it wants engineered drawings.
Settlement signs that need a call this week
- A wall or floor is dropping visibly this week.
- Water is showing at a crack that wasn't there before.
- A utility line is stretched at the wall, or the structure feels unsafe, so leave and call 911.
- Old settlement that hasn't changed against a pencil mark.
- A door that sticks with no new cracks.
Before you call about a settling house
- Mark each crack end with a pencil and date, photograph it with a coin for scale, and look again in a month.
- Write down which doors and windows stick and whether that changes with the seasons.
- Note where water comes in, if it does, and where the downspouts empty.
Permit and license position for piers and underpinning
Call your building department before the crew mobilizes, because it decides whether piering needs a permit and what drawings it wants. A job that needs a building permit can't use the under-$1,000 exemption from licensing.
Ask for the contractor's license number and check it with your state licensing agency before you sign anything.
Questions people ask
What does underpinning a foundation mean?
Underpinning stabilizes a settled footing, by pushing or screwing supports down to firmer soil or by deepening the footing. Ask someone who won't install piers whether your footing needs them.
How do I find out if my lot is in a liquefaction or landslide zone?
The California Geological Survey's EQ Zapp web map checks any address, and a seller must disclose a mapped zone at sale. In those zones cities and counties must use the maps in permitting.
Will the city want an engineer for pier work?
The state pages we have don't say whether a single-house pier job needs an engineer's stamp. In mapped liquefaction and landslide zones, the California Geological Survey says foundation soil stability must be investigated, so ask the building department what it wants for your lot.
Do I have to call 811 before pier work?
Gov. Code 4216.2 asks for notice at least two working days and no more than 14 calendar days before excavating. Which center depends on your county, USA North 811 in the north and center and DigAlert in the south, and the service is free.
What does each pier cost in California?
The figure comes from national ranges adjusted for California wages, with no counted California company price behind it. Ask for the pier count, the spacing and the permit in writing.
- CGS Seismic Hazards Program (with EQ Zapp page) Read Oct 20, 2026.
- Health and Safety Code 17953 and 17955 (leginfo) Read Oct 20, 2026.
- CSLB: C-61 Limited Specialty classifications list Read Oct 20, 2026.
- CSLB Licensing Classifications Detail: B General Building Contractor (reproduces B&P 7057) Read Oct 20, 2026.
- B&P Code 7048 (leginfo) Read Oct 20, 2026.
- CSLB Check a License Read Oct 20, 2026.
- B&P Code 7159.5 (leginfo) Read Oct 20, 2026.
- USDA NRCS Web Soil Survey home Read Oct 20, 2026.
- Government Code 4216.2 (leginfo), with the 2025 California excavation law booklet published by USA North 811 Read Oct 20, 2026.
- USA North 811 home page (county list and FAQ) Read Oct 20, 2026.
- CSLB: Do I need a building permit for my project? Read Oct 20, 2026.
- U.S. Bureau of Labor Statistics, OEWS May 2025: Cement Masons and Concrete Finishers (SOC 47-2051), California, mean hourly wage Read Oct 23, 2026.
- U.S. Bureau of Labor Statistics, OEWS May 2025: Cement Masons and Concrete Finishers (SOC 47-2051), United States, mean hourly wage Read Oct 23, 2026.
- FoundationMatch: how we estimate costs, California (editorial policy) Read Oct 23, 2026.
- Civil Code 1103.2 (leginfo) Read Oct 20, 2026.