San Diego & Los Angeles

Southern California's Premier
ADU Design + Build Firm

Q: How long does it take to build an ADU?

With Hexagon offsite manufacturing, most ADUs are completed in 3 to 6 months compared to 8 to 14 months for traditional builds.

Q: Do I need a permit to build an ADU in California?

Yes, but California recent legislation has streamlined permitting. Most cities must approve within 60 days. Hexagon handles the entire process.

Q: Can I rent out my ADU?

Yes. California law allows ADU rentals. Many clients generate $2,000 to $4,000+ per month in rental income.

Q: What types of ADUs does Hexagon build?

Detached ADUs, attached ADUs, garage conversions, and two-story ADUs — all built with our offsite manufacturing process.

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Fire-resistantWeather-resilientSolar-readyLow-maintenance

Why Build An ADU

Southern California's Trusted ADU Builder

Hexagon is the ADU builder San Diego and Los Angeles homeowners rely on. We specialize in designing and building accessory dwelling units that unlock property value, provide flexible living solutions, and maximize your investment.

Rental Income

Generate substantial passive income while retaining full property ownership.

Increase Property Value

Add hundreds of thousands to your property value with a well designed ADU.

Multigenerational Living

Create space for aging parents, adult children, or extended family while maintaining privacy.

Faster Approvals Under CA Law

Streamlined permitting for ADUs under recent California legislation.

ADU Types

ADU Types We Build

From detached units to garage conversions, we design and build the perfect ADU solution for your property.

Detached ADU

Stand-alone units offering maximum flexibility and privacy. Perfect for rear yards or corner lots.

Attached ADU

Units connected to the primary residence, maximizing land efficiency and shared utilities.

Garage Conversion ADU

Convert existing garages into functional living spaces. Quick timelines, proven design.

Two-Story ADU

Maximize unit size with two-story designs. Modern architecture, efficient layouts.

Process

Our ADU Building Process

A systematic approach to designing and building your perfect ADU.

Consultation

We meet with you to understand your vision, budget, and ADU goals. Initial feasibility assessment begins.

Site Review

Detailed property analysis. Zoning review, soil testing, utility assessment. Everything needed for informed design.

Design + Engineering

Custom ADU design tailored to your property. Structural engineering, mechanical systems, aesthetic vision.

Permitting

We handle all permit applications and approvals. Building department coordination, expedited processing.

Construction

Manufacturing begins while permits process. On-site assembly, inspections, quality assurance throughout.

Completion

Final walkthrough, address any punch list items, certificates of occupancy. Your ADU is ready to use.

Manufacturing

Off-Site Built. On-Site Perfected.

We fabricate ADU components in our facility, then assemble on-site or deliver them completed, ensuring precision, speed, and quality control that traditional site-built units cannot match.

Faster Build Time

30 to 40% quicker than traditional site-built ADUs.

Higher Quality Control

Factory precision meets onsite expertise.

Weather-Protected Construction

Built indoors, no rain delays.

Minimal Disruption

Less noise, dust, and neighborhood impact.

Predictable Scheduling

Know exactly when your ADU arrives and is completed.

Engineering

Engineered for California

Every ADU we build meets the highest standards for resilience, safety, and sustainability in Southern California's climate.

Fire-Resistant Design

Fireproof materials, Class A rated components, and wildfire-ready construction standards.

High R-Value Insulation

Superior thermal efficiency reduces energy costs year-round in any climate zone.

Steel Frame Construction

Durable, resistant to seismic activity and California earthquakes. Built to last.

Low-Maintenance Materials

Premium finishes require minimal upkeep. Spend less time maintaining, more time enjoying.

Solar-Ready Roof Design

Built-in preparation for solar panel installation. Maximize energy independence and ROI.

Low Carbon Footprint

Offsite manufacturing minimizes waste. Sustainable design reduces environmental impact.

High Acoustical Value

Sound-dampening materials create peaceful, quiet interior spaces.

Weather-Resilient

Designed to withstand coastal winds, water intrusion, and extreme weather conditions.

Offsite Advantage

Offsite Modular ADU Timeline

Our offsite manufacturing approach dramatically reduces your ADU timeline.

Traditional Site-Built

8 to 14 months

Hexagon Offsite Modular

3 to 6 months

Design + Permits

4 to 6 Weeks

3D design, engineering, and permit processing run simultaneously.

Factory Build

6 to 8 Weeks

Your ADU is manufactured in our controlled facility while site prep happens in parallel.

Site Assembly

2 to 4 Weeks

Precision onsite assembly of factory-built modules. Minimal disruption to your property.

Final Touches

1 to 2 Weeks

Utility connections, landscaping, final inspection, and key handover.

Service Areas

Areas We Serve

San Diego

Los Angeles

Financing

ADU Financing Made Simple

HELOC (Home Equity Line of Credit)

Cash-Out Refinance

Renovation Loans (FHA 203k)

ADU-Specific Lenders

Cash or Private Funding

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Common Questions

ADU FAQ

How much does it cost to build an ADU in San Diego?

ADU costs in San Diego typically range from $150,000 to $400,000 depending on size, finish level, and site conditions. Detached ADUs tend to cost more than garage conversions. Hexagon provides detailed cost breakdowns during your free feasibility assessment.

How long does it take to build an ADU?

With Hexagon's offsite manufacturing approach, most ADUs are completed in 3 to 6 months — compared to 8 to 14 months for traditional site-built ADUs. We begin factory manufacturing while permits are processing, saving months off your timeline.

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

Yes, ADUs require building permits. However, California's recent ADU legislation (AB 68, SB 13, AB 881) has streamlined the process significantly. Most cities must approve ADU permits within 60 days. Hexagon handles the entire permitting process for you.

Can I rent out my ADU?

Yes. California law allows homeowners to rent their ADUs. Many of our clients generate $2,000 to $4,000+ per month in rental income from their ADUs, depending on location, size, and finishes. ADUs are one of the best ROI home improvements available.

What types of ADUs does Hexagon build?

We build detached ADUs, attached ADUs, garage conversions, and two-story ADUs. Our offsite manufacturing process works for all types, delivering superior quality and faster timelines compared to traditional construction.

Check Your Property

Can Your Property Support an ADU?

Get a free ADU feasibility assessment. We will evaluate your property and tell you exactly what is possible.

Southern California's PremierADU Design + Build Firm