An ADU can add rental space or room for family, but choosing a builder means comparing more than floor plans. 

I rank Go ADU first for its own construction crew, guaranteed pricing tied to a detailed scope, and milestone payments. The alternatives below suit different design and coordination priorities.

Key Takeaways

• Go ADU is my top pick for guaranteed pricing, milestone billing and its own construction crew.
• Otto ADU suits design-first projects.
• ADU Build LA publishes starting prices by ADU type.
• ADU Concepts, LADU and L Square Design & Build offer other construction and coordination approaches.

How I Compared These Builders

I compared each builder’s stated service model and terms on its own website, not completed projects firsthand. Confirm Pasadena availability and current offerings directly before you sign.

Delivery model. Who handles design, permits and construction, and who actually builds?

Pricing transparency. Are starting prices, scope and payment terms clear?

Contract terms. I looked for guaranteed pricing, milestone billing, limited deposits and written change approvals.

Pasadena vs. LA City

Pasadena reviews ADUs through its own Planning and Building divisions, not the City of Los Angeles building department. 

The city’s free standard ADU plans expired at the end of 2025 and are now limited to Eaton Fire red-tagged properties, and historic properties carry extra design limits. 

Check the city’s current rules before paying for design.

1. Go ADU

Go ADU pros

• Its own crew builds the ADU, from site prep to final inspection.
• Guaranteed price tied to a detailed scope, with milestone payments and no large upfront deposit.
• Change orders proceed only with your written approval.

Go ADU cons

• Allowances may be used if your finishes aren’t chosen before pricing.
• The 4 to 6 month build estimate starts after permits are approved.

My experience with Go ADU

What stands out to me is the pairing of in-house building with clear payment terms. 

Go ADU Construction prices the job against a written scope and invoices only after each milestone is finished and verified. 

It also takes over projects another builder has already started.

Go ADU pricing

The guaranteed price and milestone billing give you a firm basis for comparing value. Ask for the written scope and any allowances so you know exactly what the agreed price covers.

2. Otto ADU

Otto ADU pros

• Custom ADUs, garage conversions and pre-designed plans.
• Planning, design and permitting handled in-house.
• Homeowner portal for plans, permits and progress updates.

Otto ADU cons

• Construction is handled by vetted subcontractors Otto bids out and oversees.
• The managed build is a separate opt-in after permits are approved.

My experience with Otto ADU

I’d shortlist Otto when design matters most. Its project list includes a Pasadena garage conversion. 

Before signing, I’d ask which subcontractors will build and how Otto supervises them.

Otto ADU pricing

Otto provides a detailed proposal with scope, timeline and pricing after a site visit. Ask how design, permitting and the managed build are each priced.

3. ADU Build LA

ADU Build LA pros

• ADU-only builder, with design, permits and construction under one contract.
• Published starting prices by ADU type.
• Pasadena listed as a service area.

ADU Build LA cons

• Final pricing depends on site conditions, scope and finish level.
• Based in Culver City.

My experience with ADU Build LA

I find published starting prices useful for an early budget check. They aren’t a substitute for a site assessment and a written, project-specific estimate.

ADU Build LA pricing

Its site lists detached ADUs from $150,000, garage conversions from $95,000 and attached ADUs from $120,000. Confirm current figures and ask whether city fees and utility work are included.

4. ADU Concepts

ADU Concepts pros

• Design-build service from permits to final walkthrough.
• Panelised light-gauge steel, assembled on site by its own crews.
• Fifteen pre-engineered layouts that can be adjusted, or fully custom designs.

ADU Concepts cons

• Steel panels bring different engineering considerations than wood framing.
• Part of a larger group of companies; confirm which one holds your contract.

My experience with ADU Concepts

I’d consider this team when exploring steel construction. Before choosing it, I’d ask how engineering and panel delivery fit the property and Pasadena’s requirements. 

Starting from pre-designed floor plans can shorten design time, but each layout still has to fit your lot.

ADU Concepts pricing

Request a custom quote. Have the proposal separate engineering, site preparation and construction costs.

5. LADU

LADU pros

• Free site visit before you commit.
• Dedicated project manager and a live project dashboard.
• Pasadena listed as a service area, with fixed-fee design.

LADU cons

• Construction goes to licensed partner contractors that LADU connects you with.
• Confirm who holds the construction contract.

My experience with LADU

LADU’s coordination model may appeal if you want one contact across the process. I’d clarify the relationship between LADU and the builder before signing.

LADU pricing

Design is quoted as a fixed fee. Request the construction price separately, plus a payment schedule.

6. L Square Design & Build

L Square pros

• Architecture, structural engineering, permits and construction kept in-house.
• One contract from first sketch to final inspection.
• Prepares permit packages for Pasadena’s own departments.

L Square cons

• Headquartered in Orange County.
• Its Pasadena pricing is published only as broad ranges; a firm quote follows a site visit.

My experience with L Square

The in-house model makes L Square worth comparing for coordinated delivery. Given its Orange County base, I’d check local crew availability and site supervision.

L Square pricing

Ask for a detailed proposal. Confirm material allowances and exclusions rather than relying on an initial estimate.

Conclusion

Go ADU is my top pick for Pasadena. Its own crew, guaranteed pricing against a written scope and milestone billing answer the main questions I’d bring to a builder shortlist.

Otto ADU is the design-first runner-up, and ADU Build LA is useful for comparing published starting budgets. 

Before signing with anyone, compare written scopes, exclusions and payment schedules, and ask who supervises construction.

FAQ

Do I need a Pasadena-specific ADU builder?

No, but the builder should serve Pasadena and understand its permit process. Ask for local examples and who will respond to city comments.

How do starting prices differ from all-in pricing?

Starting prices aren’t standardised. Ask whether each quote includes design, permits, utility connections, site preparation and city fees.

What contract terms prevent surprise change orders?

A detailed scope, clear exclusions and written change approvals reduce surprises. Ask how each builder handles unforeseen site conditions and owner-requested changes.