ADU Construction & Garage Conversions

Build Extra Living Space, Maximize Property Value & Fully Permitted & Custom Designed

Serving San Diego, CA

ADU Construction & Garage Conversion Services

Looking for more space without moving? S Squared, Inc. makes it easy to convert your garage or build a custom Accessory Dwelling Unit (ADU) right on your existing property. Whether you need a rental unit, guest suite, home office, or space for multi-generational living, we deliver fully permitted, beautifully finished solutions tailored to your home.

As a licensed and insured general contractor with 13+ years of experience, we’ve helped homeowners across San Diego unlock the hidden potential of their properties.

Licensed & Insured

3D Design Rendering

Custom-Built Solutions

On-Time Completion

Garage to Living Space Conversions

Turn your underused garage into a fully insulated, code-compliant living space with its own bathroom and kitchen. Perfect for smaller lots or in-law suites.

Detached ADU Construction

Build a brand-new, standalone ADU in your backyard with custom layouts and premium finishes. We handle design, permitting, and full buildout.

Attached ADUs

Seamlessly connect a new unit to your existing home for a cohesive layout. Includes full plumbing, electrical, HVAC, and structural work.

Design & Permitting

We create custom 3D renderings to help you visualize your unit and ensure all construction complies with California ADU regulations and local San Diego building codes.

ADU Construction in San Diego, CA

From urban neighborhoods to suburban lots, we’ve built ADUs and converted garages in San Diego, Chula Vista, El Cajon, La Mesa, Poway, Santee, and beyond. We understand the zoning requirements and offer strategic guidance for maximizing your property.

Our Reviews

All ADU and garage conversion projects can include a 3D design preview, so you can walk through your new space before we build it. Make real-time adjustments, view floorplans, and confidently approve every detail.

Ready to Build Your ADU or Convert Your Garage?

We make it simple to add flexible, livable space to your home. Whether it’s for family, guests, or income, let S Squared, Inc. help you build smarter.

Request a Free ADU or Garage Conversion Estimate

Get in touch with our expert design-build team today.

Do I need a permit to build an ADU or convert my garage?

Yes—and we handle that entire process for you. Our team works with San Diego County and local city offices to secure all required permits.

How much does a garage conversion cost?

It depends on size, features, and finishes, but conversions generally range from $60,000–$100,000+. Detached ADUs tend to cost more depending on foundation, plumbing, and electrical work.

How long does it take?

Garage conversions usually take 2–3 months. Detached ADUs may take 4–6 months, depending on complexity and permitting speed.

Can I rent out my ADU?

Yes. ADUs can be rented long-term in San Diego (and sometimes short-term, depending on your city’s regulations). They’re a great way to generate passive income.

Why Choose S Squared, Inc.?

Family-owned. Licensed. Over 20 years of experience.

We’re more than just builders – we’re your partners in turning dream spaces into real places. S Squared, Inc. is a San Diego-based construction company specializing in residential remodeling, commercial renovations, and custom pool & spa construction. Whether it’s your home or business, our team brings precision, craftsmanship, and dedication to every job.