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Custom ADU Builds & Garage Conversions Across the Bay Area
From modern accessory dwelling unit designs to complete garage conversions, we create functional, stylish ADU living spaces that expand your home’s value and flexibility.
Accessory Dwelling Units & Garage Conversions Designed for Bay Area Living
Create more space and increase property value with our modern ADU designs and custom garage conversions. As trusted ADU builders, we transform underused areas into private, fully functional living spaces tailored to your lifestyle.
Custom-Built ADU Services – Designed for How You Live
At Design By M&M, we provide complete ADU design and construction services—tailored to your needs, property layout, and long-term goals. Whether you’re building a detached accessory dwelling unit, converting a garage, or expanding with a junior ADU, we handle it all from the ground up. Unlike many ADU builders who rely on prefab units, we construct every project on-site using high-quality materials and a true custom approach.
- Detached ADUs
- Attached ADUs
- Garage Conversions
- Junior ADUs (JADUs)
- Two-story ADUs and Modern ADU designs
From ADU bathroom and kitchen design to maximizing living space and ensuring compliance with city regulations, our team ensures every detail is handled. We’re not just building space—we’re building long-term value for your property.
The Independent Suite
Design in 3 simple steps
Consult & Design
We start with a thorough consultation, creating custom designs tailored to your style and needs.
Expert Construction
Our skilled team manages every detail, from demolition to installation, ensuring precision and quality.
Enjoyment
We complete your project with meticulous attention, ensuring your complete satisfaction and a stunning new ADU.
/ FAQ
Frequently Asked Questions
If you don’t see your question answered here, please don’t hesitate to contact us directly – we’re always happy to help!”
An Accessory Dwelling Unit (ADU) is a self-contained living space built on the same lot as your primary home. A garage conversion is one type of ADU, where an existing garage is transformed into a fully livable unit with its own entrance, plumbing, and electrical systems.
On average, a custom-built ADU takes 4–6 months from design to final inspection, depending on the project complexity and permitting timeline. Garage conversions typically move faster, often completed in 3–4 months.
Yes. Whether you're building a detached ADU, converting a garage, or adding a junior ADU (JADU), you'll need permits from your local city or county. Our team handles the entire ADU permitting process for you.
Absolutely. A professionally built garage conversion ADU adds livable square footage and can significantly increase your property value. It also opens up rental income opportunities and multi-generational living solutions.
We offer:
- Detached ADUs
- Attached ADUs
- Garage Conversions
- Junior ADUs
- Two-story ADUs
Each is fully customizable to fit your lot size, lifestyle needs, and city zoning regulations.
Prefab ADUs may seem quicker, but they often come with hidden limitations and cookie-cutter designs. We specialize in custom ADUs, built from the ground up to match your home’s architecture and meet your exact needs using premium materials.
Start Your Project with Us
Ready to build, remodel, or expand? Fill out the form and our team will be in touch to discuss next steps.
Straightforward, professional, and on your terms.
- +1 (650) 899-8968
- design@designbymm.pro
- 100 South Murphy Ave STE 200 Sunnyvale CA 94086

License number #1082131