Interior Conversion ADU
Convert Unused Interior Space into a Rental Unit
About Our Interior Conversion ADU Services
An interior conversion ADU repurposes existing space within your home - such as a basement, bonus room, or unused wing - into a fully independent dwelling unit with its own kitchen, bathroom, and entrance. Unlike a JADU, an interior conversion ADU can exceed 500 square feet if the existing space allows, and it must have its own bathroom (no sharing with the main home).
CCS Inc. evaluates your home's existing layout to identify the optimal conversion opportunity. Our architects design the unit to maximize livability within the existing footprint, while our engineers verify that structural modifications (such as adding a separate entrance or rerouting plumbing) are safe and code-compliant. We handle everything from design to permits to construction.
Interior conversions offer a middle ground between the minimal scope of a JADU and the full expense of new construction. They are especially valuable in larger homes with underused square footage, split-level homes with natural separation, or homes with walk-out basements. Because no new foundation or exterior walls are needed, costs and timelines are significantly reduced compared to attached or detached ADUs.
Why Choose CCS for Interior Conversion ADU?
No new foundation or exterior construction required
Utilizes existing underused space in your home
Lower cost and faster timeline than new-build ADUs
Can exceed 500 sqft (unlike JADUs)
Adds significant rental income and property value
Minimal impact on exterior appearance and yard
How It Works
1
Home walkthrough to identify convertible spaces
2
Floor plan design with separate entrance, kitchen, and bathroom
3
Structural and MEP engineering as needed
4
Permit filing and plan check management
5
Interior build-out and final inspection
Free Property Tools
Use our free online tools to research your property and explore your options.
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Ready to Get Started?
Schedule a free consultation with our interior conversion adu experts. We'll assess your project and provide a detailed plan.
