Home addition cost in Modesto, CA
Local estimate from BLS wage data and BEA price levels. Reviewed Nov 4, 2026.
- Typical range (300 sq ft)
- $43,500 – $87,900
- Per sq ft
- $143 – $286
- before permit
- Versus US midpoint
- +14%
- US $57,500
- Rank of 300 metros
- #27
- 1 = most expensive
Local price for a home addition in the Modesto area: $43,500 to $87,900 for 300 sq ft. The low end is a basic job on easy ground; the high end is a premium spec with harder access. The midpoint runs 14% higher than the US figure. Carpenters earn a median of $35.45 an hour in the Modesto area, 22% above the US median of $29.12.
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Estimated cost for 300 sq ft in Modesto, CA, standard level
$56,800 to $74,600
About $186 to $243 per sq ft before permits. Labor is about 69% of the bill.
| Part | Low | High |
|---|---|---|
| Materials | $16,400 | $21,500 |
| Labor | $39,400 | $51,500 |
| Permits and fees | $990 | $1,600 |
| Total | $56,800 | $74,600 |
Cost breakdown for 300 sq ft in Modesto, CA
| Part of the job | Low | Midpoint | High | Share |
|---|---|---|---|---|
| Materials | $12,600 | $18,900 | $25,200 | 29% |
| Labor | $30,300 | $45,500 | $60,600 | 69% |
| Permits and fees | $520 | $1,300 | $2,100 | 2% |
| Total | $43,500 | $65,700 | $87,900 | 100% |
Where the Modesto price comes from
We price the labor side from BLS wage data for 6 trades: carpenters at 50%, cement masons and concrete finishers at 10%, electricians at 10%, plumbers, pipefitters and steamfitters at 10%, drywall and ceiling tile installers at 10%, roofers at 10%. Weighted together, Modesto wages are 1.19 times the national level. Labor makes up about 69% of the midpoint estimate (67% at national prices).
Materials are scaled with BEA's regional price parity for goods. Modesto is at 105.2 against 100 for the US, so a materials line of $18,000 nationally becomes $18,900 here (midpoint, 300 sq ft). Permits follow the all-items index of 104.1: $520 to $2,100.
How Modesto compares
Of the five closest metros, 2 are cheaper than Modesto. Stockton is the lowest at about $63,300 (midpoint, 300 sq ft), 30 miles away.
| Area | Range | Midpoint | vs. here |
|---|---|---|---|
| Modesto, CAthis page | $43,500 – $87,900 | $65,700 | |
| Stockton, CA30 miles | $41,900 – $84,800 | $63,300 | −4% |
| Merced, CA30 miles | $42,200 – $85,500 | $63,800 | −3% |
| San Jose, CA50 miles | $48,400 – $97,800 | $73,100 | +11% |
| Santa Cruz, CA65 miles | $44,100 – $89,300 | $66,700 | +2% |
| Vallejo, CA70 miles | $43,700 – $88,500 | $66,100 | +1% |
| California (statewide) | $43,800 – $88,800 | $66,300 | +1% |
| United States | $38,000 – $77,000 | $57,500 | −12% |
Out of the 300 metros we cover, Modesto ranks #27 for the cost of this job (#1 is the most expensive). Statewide, Modesto is 1% below the California figure.
Elsewhere in California
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Los Angeles, CA | 6,271,560 jobs | $43,600 – $88,400 | $66,000 | level |
| San Francisco, CA | 2,373,920 jobs | $49,600 – $100,500 | $75,000 | +14% |
| Riverside, CA | 1,716,760 jobs | $41,300 – $83,700 | $62,500 | −5% |
| San Diego, CA | 1,538,060 jobs | $44,000 – $89,200 | $66,600 | +1% |
| San Jose, CA | 1,134,970 jobs | $48,400 – $97,800 | $73,100 | +11% |
| Sacramento, CA | 1,080,590 jobs | $42,800 – $86,700 | $64,700 | −1% |
Metros of a similar size
Big cities and small ones price differently, so here is Modesto against the 4 metros with the closest total employment.
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Savannah, GA | 198,360 jobs | $33,100 – $67,100 | $50,100 | −24% |
| Corpus Christi, TX | 192,580 jobs | $32,400 – $65,800 | $49,100 | −25% |
| Manchester, NH | 199,560 jobs | $38,400 – $77,800 | $58,100 | −12% |
| Boulder, CO | 192,390 jobs | $37,800 – $76,600 | $57,200 | −13% |
Who does the work: Modesto trade wages
The labor line is built from BLS wage data, one trade at a time. This job draws on 6 trades. We compare each trade's local median with the US median, weight the ratios by how much of the job each trade does, and apply the blend to the national labor cost. For Modesto the blend is 1.19.
Carpenters (47-2031), 50% of the weighting: a median of $35.45 an hour, 22% above the US median of $29.12. The middle half of them earn between $28.52 and $40.15 an hour. About 1,430 work in the metro. That is 73.2 per 10,000 jobs, compared with 43.1 nationally, which suggests plenty of local crews to bid.
Cement masons and concrete finishers (47-2051), 10% of the weighting: a median of $36.78 an hour, 34% above the US median of $27.41. The middle half of them earn between $28.19 and $48.46 an hour. About 350 work in the metro. That is 17.9 per 10,000 jobs, compared with 13.3 nationally, which suggests plenty of local crews to bid.
For electricians (47-2111, weighted 10%) the local median is $36.88 an hour, which is 21% above the national $30.38. The middle half of them earn between $28.42 and $48.36 an hour. BLS counts 770 of them working in the area, 39.4 for every 10,000 jobs (US: 48.7), so the local bench is thinner than average.
Plumbers, pipefitters and steamfitters (47-2152), 10% of the weighting: a median of $30.42 an hour, in line with the US median of $30.67. The middle half of them earn between $26.76 and $38.00 an hour. About 470 work in the metro. That is 24.1 per 10,000 jobs, compared with 30.0 nationally, so expect fewer local crews to bid.
For drywall and ceiling tile installers (47-2081, weighted 10%) the local median is $31.62 an hour, which is 12% above the national $28.33. The middle half of them earn between $26.04 and $40.07 an hour. BLS counts 400 of them working in the area, 20.5 for every 10,000 jobs (US: 5.3), so the local bench is deeper than average.
Roofers (47-2181), 10% of the weighting: a median of $30.26 an hour, 14% above the US median of $26.65. The middle half of them earn between $28.54 and $35.26 an hour. About 290 work in the metro. That is 14.9 per 10,000 jobs, compared with 8.7 nationally, which suggests plenty of local crews to bid.
A quick sensitivity check: moving the lead trade (carpenters) from the median to the 75th percentile wage adds about $3,100 to the midpoint estimate; the 25th percentile takes off about $4,550. That is a swing of roughly 6.9% to 4.7% of the total, which is useful for judging whether a bid reflects wages or something else, such as scope or margin.
Modesto has 195,230 jobs in total (BLS, May 2025), ranking 117th by size among the 300 metros on this site.
| Trade | Weight | 25th pct | Median | 75th pct | US median | Ratio | Level used |
|---|---|---|---|---|---|---|---|
| Carpenters (47-2031) | 50% | $28.52 | $35.45 | $40.15 | $29.12 | 1.22 | metro |
| Cement masons and concrete finishers (47-2051) | 10% | $28.19 | $36.78 | $48.46 | $27.41 | 1.34 | metro |
| Electricians (47-2111) | 10% | $28.42 | $36.88 | $48.36 | $30.38 | 1.21 | metro |
| Plumbers, pipefitters and steamfitters (47-2152) | 10% | $26.76 | $30.42 | $38.00 | $30.67 | 0.99 | metro |
| Drywall and ceiling tile installers (47-2081) | 10% | $26.04 | $31.62 | $40.07 | $28.33 | 1.12 | metro |
| Roofers (47-2181) | 10% | $28.54 | $30.26 | $35.26 | $26.65 | 1.14 | metro |
| Blended | 100% | 1.19 | |||||
Cost by quality level and size in Modesto
The cited range is split into basic, standard and premium bands, then scaled to Modesto. Bands overlap, because plenty of standard jobs cost as much as a light premium one. Sizes run from bump-out (100 sq ft) to large suite (600 sq ft).
Basic
$43,500 to $61,200
Bump-out or simple room without plumbing
Standard
$56,800 to $74,600
Standard room addition with HVAC and electrical
Premium
$70,100 to $87,900
Large addition with bath or kitchen and a new foundation
| Size | Basic | Standard | Premium |
|---|---|---|---|
| bump-out (100 sq ft) | $14,800 – $21,200 | $19,600 – $25,900 | $24,400 – $30,700 |
| 20x20 room (400 sq ft) | $57,800 – $81,300 | $75,400 – $98,900 | $93,000 – $116,500 |
| large suite (600 sq ft) | $86,400 – $121,500 | $112,500 – $147,500 | $139,000 – $174,000 |
The best months for home addition in Modesto
Climate numbers on this page come from NOAA's 1991-2020 U.S. Climate Normals at the nearest suitable station, Modesto City Co Ap (5 miles from the city center). They are 30-year averages, so any one year can run hotter, colder or wetter.
For digging, grading and setting material in the ground, the comfortable months in Modesto are September through May: 9 of 12. Outside them, June, July and August have an average daytime high of 90°F or more.
Modesto gets about 12 inches of precipitation in a normal year. The wettest months are January, February and December (2.6 inches in January). Inside the workable window, September and October are the driest, at 0.1 and 0.6 inches. The station averages about 90 days a year at 90°F or above.
We do not adjust the estimate by month, because we have no reliable published data on seasonal pricing. It is still worth asking contractors whether an off-peak start date changes their bid.
| Month | Avg high °F | Avg low °F | Precip (in) | For this job |
|---|---|---|---|---|
| Jan | 56 | 39 | 2.6 | Workable |
| Feb | 62 | 42 | 2.2 | Workable |
| Mar | 68 | 45 | 1.8 | Workable |
| Apr | 74 | 48 | 1.0 | Workable |
| May | 82 | 54 | 0.7 | Workable |
| Jun | 90 | 59 | 0.1 | Hot |
| Jul | 95 | 63 | 0.0 | Hot |
| Aug | 94 | 62 | 0.0 | Hot |
| Sep | 89 | 59 | 0.1 | Workable |
| Oct | 79 | 52 | 0.6 | Workable |
| Nov | 66 | 43 | 1.1 | Workable |
| Dec | 56 | 39 | 2.2 | Workable |
Related projects, priced for Modesto
Jobs that often go together with home addition are priced below at their usual sizes, using the same Modesto wage and price inputs. Compared with national midpoints, detached garage comes out highest (+15%) and bathroom remodel lowest (+5%); the gap comes from the trades each job uses.
| Project | Size | Range | vs. US |
|---|---|---|---|
| Kitchen remodel | 120 sq ft | $19,700 – $33,600 | +7% |
| Bathroom remodel | 45 sq ft | $4,950 – $24,500 | +5% |
| Detached garage | 576 sq ft | $33,200 – $66,600 | +15% |
| Roof replacement | 2,000 sq ft of roof | $6,900 – $13,900 | +12% |
Why two Modesto quotes can differ
Foundation
A foundation, framing, roofing and matching exterior finishes all have to be built before the interior work starts.
Type of addition
A new room is $125-$250 per sq ft; a bump-out $85-$200; an attic conversion $50-$150; a garage conversion $50-$200 (HomeGuide).
Plumbing and fixtures
Adding a bathroom or kitchen drives the price up the most.
Get 3 local quotes
Tell us about the job and we will try to connect you with up to three local contractors for written quotes. It is free and you are under no obligation to hire. Your estimate of $56,800 to $74,600 for Modesto, CA is attached.
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Home addition in Modesto: your questions
+How much does it cost to build a home addition in Modesto?
For 300 sq ft, expect $43,500 to $87,900 in the Modesto area. A standard-spec job lands at $56,800 to $74,600. Small jobs usually cost more per sq ft and large ones less.
+What is the price per sq ft for home addition in Modesto?
About $143 to $286 per sq ft for materials and labor, plus $520 to $2,100 for the permit if one is needed. The US range is $125 to $250.
+Is home addition cheaper in Modesto or Stockton?
Stockton is 30 miles away. The midpoint for 300 sq ft there is $63,300, which is 4% less than Modesto ($65,700). Wage and materials indexes both feed that gap.
+How much of the bill is labor in Modesto?
About 69% at the midpoint, or $45,500 out of $65,700. Materials are 29% and permits 2%. Nationally, labor is 67%.
+What would 20x20 room (400 sq ft) cost in Modesto?
$57,800 to $116,500. Pick a different size in the estimator above to get your own number.
+Does home addition need a permit in Modesto?
Often, but rules are set by your city or county building office, so call before you hire. Budget $520 to $2,100 for fees in the Modesto area (our national range of $500 to $2,000 scaled by the local price level).
+Is Modesto expensive for home addition compared with the rest of California?
Modesto is 1% below the California statewide estimate ($66,300 at the midpoint). We cover 23 metros in California; see the state page to compare them.
+What do carpenters earn in Modesto?
The BLS median is $35.45 an hour in the Modesto area, compared with $29.12 nationally. The 25th to 75th percentile range is $28.52 to $40.15.
+What do basic and premium home addition work cost in Modesto?
For 300 sq ft, basic work runs $43,500 to $61,200 and premium work $70,100 to $87,900. Basic means: bump-out or simple room without plumbing. Premium means: large addition with bath or kitchen and a new foundation.
+When is the best time to build a home addition in Modesto?
Based on NOAA 1991-2020 normals, the comfortable months for this kind of work are September through May. September and October are typically the driest of those months. Local contractors' schedules matter as much as the weather, so book early for the busy months.
Home addition near Modesto
Where these numbers come from
Base prices are national ranges from the sources below. We scale labor by local BLS wages, materials by BEA goods prices and permits by the BEA all-items price level. Full method on the methodology page.
- HomeGuide: How Much Does a Home Addition Cost? (2026) (accessed November 4, 2026)
- Cost to Renovate: Renovation Labor Report 2026: Where the Money Goes (accessed November 4, 2026)
- HomeGuide: 2026 Building Permit Costs | Fees & Cost Calculator (accessed November 4, 2026)
- BLS Occupational Employment and Wage Statistics, May 2025
- BEA Regional Price Parities, 2024
- NOAA NCEI U.S. Climate Normals, 1991-2020
Note on derived figures: Materials = 32% of the installed price, from Cost to Renovate's mid-range 'Structural' category split (56% labor, 32% materials, 11% permits and design). It is a category average rather than an addition-specific figure.