Expanding Your Space — ADUs & Additions That Feel Like They’ve Always Belonged

From extra bedrooms and expanded living areas to fully detached ADUs, we design and build thoughtful additions that integrate seamlessly with your home. Ellis Development handles everything — design, permits, construction, and final finishes — to deliver spaces that are functional, beautiful, and built to last.

Smart Expansions, Seamless Additions

Whether you're adding livable square footage or building a fully independent ADU, we create spaces that feel like they’ve always belonged. From layout and permitting to buildout and finish work, Ellis Development delivers additions and accessory dwelling units that integrate naturally, perform beautifully, and add lasting value — all with the clarity and care we’re known for.

View of a modern backyard with a swimming pool, a white building with black trim, and outdoor furniture. The building has a door and a window, with warm interior lighting visible through the glass. There's greenery and a fence surrounding the yard.

  • We design and build custom home additions that feel like a natural extension of your space — not an afterthought. Whether it’s a new bedroom, expanded living area, or a primary suite retreat, our additions are crafted to enhance comfort, function, and flow. Every expansion is thoughtfully planned, seamlessly integrated, and built to match the way you live.

    Additions starting at $250 Per sq/ft

  • Turn underused square footage into livable space with a thoughtfully designed garage conversion. We specialize in building attached ADUs that seamlessly integrate with your existing home while creating functional, private living quarters — ideal for extended family, guests, or rental income. From zoning and structural assessments to permits, layout design, and build-out, Ellis Development handles every step with precision and care.

    Attached ADU’s Starting at $300 Per Sq/Ft

  • Detached living spaces offer unmatched flexibility, privacy, and long-term value — and at Ellis Development, we treat them with the same level of craftsmanship and intention as a full-scale custom home. Whether you’re building a guest house, a poolside retreat, or a fully equipped backyard ADU, we design and construct detached dwellings that blend seamlessly with your property while serving a purpose all their own.

    As licensed ADU builders, we navigate California’s evolving code requirements to ensure every structure is fully compliant — from lot setbacks and utility connections to Title 24 energy standards and city-specific permitting. These dwellings can function as private rental units, multigenerational suites, office or creative spaces, or simply a well-appointed extension of your home.

    From initial concept and architectural design to finish work and final inspection, we manage the entire process — delivering detached structures that are thoughtful, functional, and built to last.

    Starting at $350 Per Sq/Ft