ADU Design in California
NSBW Architects provides permit-ready ADU (Accessory Dwelling Unit) design services for homeowners across California. Whether you are building a backyard cottage for rental income, a guest house for family, or a home office, we deliver complete architectural drawings that meet California’s ADU regulations and local building codes.
What Is an ADU?
An Accessory Dwelling Unit is a secondary housing unit built on an existing residential lot. California has been at the forefront of ADU legislation, making it easier than ever for homeowners to add a unit to their property. ADUs can be detached structures in the backyard, attached additions to the main house, or conversions of existing garages and basements.
Since 2020, California law has streamlined ADU approvals significantly. Most ADUs under 800 sq ft are exempt from impact fees, and cities cannot impose minimum lot size requirements for ADUs. This makes them one of the most accessible and financially rewarding home improvement investments available to California homeowners.
Our ADU Design Process
Our process begins with understanding your site, your goals, and your budget. We assess your lot’s zoning, setback requirements, and utility connections before proposing a design concept. From there, we develop full architectural drawings including floor plans, elevations, sections, site plans, and construction details — everything you need to submit for permits.
We handle ADU projects from concept through permit-ready documentation. Our deliverables include architectural plans, structural coordination, Title 24 energy compliance, and all documentation required by your local building department. We work with local structural engineers and Title 24 consultants to ensure a smooth permitting process.
ADU Types We Design
We design all types of ADUs permitted under California law: detached ADUs (standalone backyard units, typically 400–1,200 sq ft), attached ADUs (additions to the existing home), garage conversions (converting an existing attached or detached garage into a living unit), Junior ADUs (JADUs, up to 500 sq ft, created within the existing footprint of the primary home), and multi-family ADUs (for properties with existing multi-family buildings).
Why Choose NSBW Architects for Your ADU
With over 200 projects delivered across India and the United States, NSBW Architects brings a depth of residential design experience that most ADU-focused firms cannot match. We don’t use cookie-cutter templates — every ADU we design is tailored to the specific lot, the homeowner’s needs, and the neighborhood context.
Our proficiency in BIM modeling and Revit means your drawings are precise, coordinated, and ready for construction. We also bring a strong design sensibility — your ADU should not only meet code requirements but also look and feel like a thoughtful, well-designed home.
California ADU Regulations at a Glance
California’s statewide ADU laws (Government Code Sections 65852.2 and 65852.22) establish baseline rules that all cities must follow. Key provisions include: no minimum lot size requirement, 4-foot side and rear setbacks for detached ADUs, no owner-occupancy requirement for ADUs permitted before 2025, no parking requirement if the ADU is within half a mile of public transit, and a maximum size of 1,200 sq ft for detached ADUs (or 1,000 sq ft for one-bedroom and 850 sq ft for studios in some jurisdictions). Local rules may offer additional flexibility, so we always verify with your specific city before beginning design.
Get Started on Your ADU
Ready to add an ADU to your California property? Contact us for a free initial consultation. We will review your lot, discuss your goals, and provide a clear scope and timeline for your project. We respond within 24 hours.
NSBW Architects
Email: nsbw@nsbw.in