About Us

USModular is a second generation, full service, design build general contractor with over 35 years of experience. We specialize in factory built/ prefabricated Accessory Dwelling Units and single family homes. We have an A+ Rating with the Better Business Bureau and we have been featured in Forbes. We are your “One-Stop-Shop” for your detached ADU project in Southern California. We handle everything from design, permits, installation and all site work. Don’t over complicate your ADU project. USModular builds FASTER – BETTER – GREENER and FOR LESS!

Get a Free ADU Site Assessment

Is one of our ADUs right for your property? Enter the complete street address below to find out.

ADUs 160 sq ft to 1,200 sq ft

Park Model RV "Tiny Home" Up to 399 SF
ADU Models 400 SF to 750 SF
ADU Models 751 SF to 950 SF
ADU Model 951 SF to 1,200 SF

Why choose Us?

Full service

USModular is Southern California’s premier full service design and build general contractor for the construction of your prefab  Accessory Dwelling Unit (“ADU”).

All-inclusive pricing

USModular works with several lender partners to assist our clients with funding for their ADU project.

Fast build

Don’t over complicate your ADU project.  USModular builds FASTER – BETTER – GREENER and FOR LESS!

How do we start

We thought you would never ask!
Review the series of floor plans that we offer.​ Then contact us and provide your project site address and your preferred ADU model

New 2020 California Laws

California is in a housing crisis, both of physical houses and affordability. ADUs help the crisis by getting more homes and lowering cost to build as land and utility infrastructure is already in place (2 of the biggest costs to build a new home). New State of California ADU laws include:

  • ADUs can be up to 1,200 sq. ft. regardless of the size of primary dwelling unit (as long as you meet setbacks and FAR)

  • Setbacks reduced to 4’ side and rear yard

  • Parking requirement for ADU waived


Building with us

The peace of mind is in the details.

Our process

Additional Space for family members – grandparents, kids, and relatives


Our clients are not required to use one of our lender partners for financing. 

Standard features

’Prefab’ is shorthand for ‘Previously Fabricated’, meaning it was built in a factory and is reassembled or finished onsite.

We help teams build a business of their dreams with our services.

Identify Goals

We work closely with you to understand and identify your business goals that can be converted into an actionable plan.

Bring Ideas to Life

The ideas and plans that we’ve jotted will then be brought to life. We help and guide you to take the first step and set things up.

Business Expansion

Setting up a business is not enough. We help you think ahead and encourage you to expand your business with a full-proof plan.

Trusted by Leaders

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Priscila Markus
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Kyle Hoffman
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Jason Myles

Customer stories

See why people love building with us.

Leslie-Oceanside CA

“Working with USModular for ADU was easy they did it all. Love my new ADU!

Dora-Santa Ana CA

“I’m now living next to my daughter and grandkids. Glad the USModular team worked with city to get
permits and build ADU. Watching crane lift my house into backyard was very exciting

Tamara – Los Angeles CA

Started my ADU just before Covid shutdown it was a trying time but USModular persevered and got
permits and built me a beautiful ADU

Mary-Vista CA

I have a duplex and was able to permit 2 additional ADUs on my property. No brainer!! I will double my
rental income. Thanks”