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ADU Builders in Claremont, CA

51 builders · ranked by Google rating and review volume · 26 CSLB license verified

★ Featured ADU builder

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Put your ADU company at the top of this page, in front of Claremont homeowners who are comparing builders right now. Includes your logo, project photos, a direct call button and a link to your website.

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With roughly 37,266 residents at the 2020 Census, Claremont is one of Los Angeles County's established communities. We found 51 ADU builders and contractors that show up for Claremont homeowners on Google Maps, 1 of them based in the city itself. Their average Google rating is 4.8 stars. 17 market themselves specifically as ADU builders, and 1 mention garage conversions. 26 have a matched, active CSLB license shown with a verified badge. The top-rated by our review-weighted score are JNC Construction, Skilled Home Builders and Hostetler Construction Inc..

Los Angeles leads California in ADU permits. Common projects here include garage conversions on older lots, detached backyard units on deep lots, and hillside sites where access and grading drive the cost.

#1

JNC Construction

5.0 (143 Google reviews)

9360 Base Line Rd Ste H, Rancho Cucamonga, CA 91701

Serves Claremont · based in Rancho Cucamonga
Remodels & additionsHome builderGeneral contractor
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#5

St Paul Contracting

5.0 (25 Google reviews)
✔ CSLB License Verified #1104071

9650 Business Center Dr Bldg 17, Suite 131, Rancho Cucamonga, CA 91730

Serves Claremont · based in Rancho Cucamonga
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#8

Khan Construction Co.

4.9 (37 Google reviews)
✔ CSLB License Verified #700519

5802 Aurora Ave, Jurupa Valley, CA 91752

Serves Claremont · based in Jurupa Valley
Home builderGeneral contractor
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#11

Backyard Estates

4.9 (30 Google reviews)
✔ CSLB License Verified #1076065

2335 W Foothill Blvd #18, Upland, CA 91786

Serves Claremont · based in Upland
Home builder
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#12

Capy Construction

5.0 (15 Google reviews)
✔ CSLB License Verified #1120565

Service-area business · Walnut

Serves Claremont · based in Walnut
Remodels & additionsHome builderGeneral contractor
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#13

Lopez United Inc

5.0 (14 Google reviews)
✔ CSLB License Verified #841932

11991 Silicon Ave, Chino, CA 91710

Serves Claremont · based in Chino
Remodels & additionsHome builderGeneral contractor
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#15

Salem Builders

5.0 (13 Google reviews)

Service-area business · Montclair

Serves Claremont · based in Montclair
Remodels & additionsHome builderGeneral contractor
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#30

H&H Construction

5.0 (4 Google reviews)
✔ CSLB License Verified #868003

120 W Dayton St, Upland, CA 91786

Serves Claremont · based in Upland
Remodels & additionsGeneral contractor
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#31

DMAX Construction

5.0 (4 Google reviews)

621 N Monte Vista Ave, San Dimas, CA 91773

Serves Claremont · based in San Dimas
Remodels & additionsGeneral contractor
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#32

The ADU Pro

4.7 (15 Google reviews)
✔ CSLB License Verified #1128679

15338 Central Ave, Chino, CA 91710

Serves Claremont · based in Chino
ADU specialistHome builderGeneral contractor
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#35

ADU Experts

5.0 (3 Google reviews)

Service-area business · Azusa

Serves Claremont · based in Azusa
ADU specialistGeneral contractor
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#37

OSHI Construction Inc.

5.0 (2 Google reviews)
✔ CSLB License Verified #990408

10722 Arrow Route Ste 304, Rancho Cucamonga, CA 91730

Serves Claremont · based in Rancho Cucamonga
Remodels & additionsHome builderGeneral contractor
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#39

R&R Improvements

4.6 (10 Google reviews)
✔ CSLB License Verified #1087664

16226 Windcrest Dr, Fontana, CA 92337

Serves Claremont · based in Fontana
Remodels & additionsHome builderGeneral contractor
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#43

BCM Group Inc

4.0 (4 Google reviews)
✔ CSLB License Verified #968356

9339 Feron Blvd, Rancho Cucamonga, CA 91730

Serves Claremont · based in Rancho Cucamonga
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#45

CalHome ADU

1.0 (1 Google reviews)

2540 Fulton Rd, Pomona, CA 91767

Serves Claremont · based in Pomona
ADU specialistGeneral contractor
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#48

Ironbridge ADU

No rating yet (0 Google reviews)

Service-area business · Upland

Serves Claremont · based in Upland
ADU specialistPrefab / modularHome builder
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#51

Premier ADU

No rating yet (0 Google reviews)

Service-area business · Upland

Serves Claremont · based in Upland
ADU specialistGeneral contractor
CallWebsiteView profile

Permits and pre-approved plans in Claremont

ADU permits in Claremont go through the city's building or planning department. Under AB 1332, every California city and county had to set up a pre-approved ADU plan program by January 1, 2025, so ask Claremont whether it has approved plans you can use. See our pre-approved plans guide and California ADU law summary.

Planning an ADU in Claremont? Start here

How to Choose an ADU Builder in Southern California: 15-Point ChecklistPrefab and Modular ADUs in California: Real Costs, Permits and PitfallsJADU vs ADU in California: Size, Rules, Cost and Which to BuildHow Much Does It Cost to Build an ADU in Southern California?

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Claremont ADU FAQ

How many ADU builders serve Claremont?

Our directory lists 51 ADU builders and contractors that appear for Claremont on Google Maps, including companies based in nearby Los Angeles County communities.

Do I need a permit to build an ADU in Claremont?

Yes. ADUs need a building permit from the City of Claremont, which must approve or deny a complete application within 60 days under state law. Many cities also offer pre-approved plans that speed up review.

How much does an ADU cost in Claremont?

Most Southern California detached ADUs land around $350 to $550 per square foot all-in, garage conversions around $200 to $350, and JADUs around $50,000 to $150,000. Use our ADU cost estimator and get three itemized bids.

How are Claremont ADU builders ranked here?

By Google rating weighted by the number of reviews, so a 4.9 with 200 reviews ranks above a 5.0 with 3. Featured placements are clearly labeled and don't affect the organic ranking.

Nearby cities in Los Angeles County

Los Angeles 118Long Beach 119Santa Clarita 27Glendale 117Lancaster 12Palmdale 12Pomona 67Torrance 98Pasadena 100Downey 28West Covina 68El Monte 24
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