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ADU Builders & Contractors in Altadena, CA

Building an ADU in Altadena? You'll find 91 licensed contractors in the area, ready to help. Altadena's ADU market continues to grow as homeowners invest in additional living space, rental income, and multi-generational housing.

📊 ADU Quick Facts for Altadena

Avg. Cost/sqft

$195-$370

Permit Timeline

60-120 weeks

Max Size

1200 sqft

Setbacks

4ft sides

Top 91 ADU Contractors in Altadena

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#1AIR CONDITIONING SOLUTIONS INC

Altadena, CA

Air Conditioning Solutions Inc — licensed ADU contractor in Altadena, CA. Detached ADU construction. 20+ years experience.

View Profile📞 (626) 797 0547
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#2ALTADENA GENERAL CONTRACTORS INC

Altadena, CA

Altadena General Contractors Inc — licensed ADU contractor in Altadena, CA. Detached ADU construction.

View Profile📞 (818) 800 6296
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#3TAMAMIAN CONSTRUCTION

Altadena, CA

Tamamian Construction — licensed ADU contractor in Altadena, CA. Detached ADU construction. 20+ years experience.

View Profile📞 (818) 720 9350
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#4PAYNE GERALD PLUMBING & CONSTRUCTION

Altadena, CA

Payne Gerald Plumbing & Construction — licensed ADU contractor in Altadena, CA. Detached ADU construction. 15+ years experience.

View Profile📞 (626) 429 0604
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#5ELECTRO CONSTRUCTION CORP

Altadena, CA

Electro Construction Corp — licensed ADU contractor in Altadena, CA. Detached ADU construction. 78+ years experience.

View Profile📞 (323) 660 4141
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#6ELIZABETH BRUNWIN

Altadena, CA

Elizabeth Brunwin — licensed ADU contractor in Altadena, CA. Detached ADU construction. 16+ years experience.

View Profile📞 (626) 253 5616
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#7UNIFIED HOME SOLUTIONS INC

Altadena, CA

Unified Home Solutions Inc — licensed ADU contractor in Altadena, CA. Detached ADU construction.

View Profile📞 (818) 468 6480
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#8CAMBUILD CONSTRUCTIONS

Altadena, CA

Cambuild Constructions — licensed ADU contractor in Altadena, CA. Detached ADU construction. 11+ years experience.

View Profile📞 (626) 243 3156
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#9CLASSIE BUILDING SERVICE AND CONSTRUCTION

Altadena, CA

Classie Building Service And Construction — licensed ADU contractor in Altadena, CA. Detached ADU construction. 29+ years experience.

View Profile📞 (626) 421 2478
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#10BERTIN BROTHERS CONSTRUCTION INC

Altadena, CA

Bertin Brothers Construction Inc — licensed ADU contractor in Altadena, CA. Detached ADU construction. 34+ years experience.

View Profile📞 (626) 831 2264
View All 91 Contractors →

💰 How Much Does an ADU Cost in Altadena?

Garage Conversion

$67,500 - $127,500

Converting existing garage to living space

Detached ADU

$145,000 - $320,000

New standalone unit (600-1,200 sqft)

Permit & Fees

$1,108 - $5,108

Plan check, permits, utility connections

* Costs vary based on size, finishes, site conditions, and contractor. Get quotes from multiple Altadena contractors to compare pricing.

❓ Frequently Asked Questions About ADUs in Altadena

How much does it cost to build an ADU in Altadena?▼
The average cost to build an ADU in Altadena ranges from $145,000 to $320,000, or approximately $195 to $370 per square foot. Garage conversions typically cost $67,500 to $127,500.
How long does it take to get an ADU permit in Altadena?▼
The ADU permit process in Altadena typically takes 60 to 120 weeks. California law requires cities to approve or deny ADU permits within 60 days of receiving a complete application.
What are the ADU size limits in Altadena?▼
In Altadena, detached ADUs can be up to 1200 square feet. Attached ADUs are limited to 50% of the primary dwelling or 1,200 sqft, whichever is less. Junior ADUs (JADUs) are limited to 500 sqft and must be within the existing home.
What is the setback requirement for ADUs in Altadena?▼
Altadena requires 4-foot setbacks from side property lines and 4-foot setbacks from rear property lines for new ADU construction. Converted structures (like existing garages) may maintain their current setbacks.
Do I need to provide parking for my ADU in Altadena?▼
No parking is required for ADUs in Altadena if your property is within half a mile of public transit, in a historic district, part of an existing multi-family building, or if the ADU is a garage conversion. Otherwise, one space may be required.

Also See ADU Contractors In

Los Angeles (3215)San Diego (2582)San Francisco (2170)Sacramento (1551)Riverside (925)Fresno (904)Anaheim (784)Irvine (760)

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