ADU Design
Permit-Ready ADU Design & Engineering for California Homes
From site planning and floor layouts to structural engineering and submittal—we manage the full ADU design and permit process.
Our Stats
California Trusted Architectural & Structural Engineering
Years of Experience
Projects Delivered
Permit Approval Rate
Professional Team Members
Cecilia Home provides licensed architectural and structural engineering services for ADUs, additions, remodeling, wall removals, and permit-ready plans. We make the process simple, clear, and stress-free.
With 20+ years of experience, 2,000+ completed projects, and a 95% approval rate, our California-registered engineers deliver accurate, code-compliant designs trusted by homeowners statewide.
Trust & Collaboration
ADU Plans Approved Across California Cities
Our ADU plans are consistently approved across California. With expertise in ADU codes and local review standards, we help homeowners reduce corrections and secure permits faster.
All Featured Projects Are Real, City-Approved Plans
Why You Need This
Why Build an ADU in California?
ADUs offer one of the highest ROI opportunities for California homeowners—when executed with proper planning, engineering, and permitting.
Risks of Poor ADU Planning
- Incorrect setbacks and height limits cause permit rejectionADU zoning varies by city; misinterpretation leads to costly redesigns.
- Improper utility planning increases construction costsSewer, electrical load, and gas line upgrades must be calculated early.
- Delays from incomplete architectural or structural plansCities require detailed documents—missing items trigger correction cycles.
Benefits of Building an ADU
- Increase property value immediatelyFinished ADUs add 20–40%+ to property resale value in many CA regions.
- Generate passive rental incomeLong-term rentals, student housing, or multi-generational living options.
- Statewide ADU laws make approval easierCalifornia mandates cities to approve compliant ADU plans within legal timelines.
Why Choose Cecilia Home
- Full architectural + structural ADU plan setsPermit-ready drawings tailored to each city’s ADU ordinance.
- Fast approval turnaroundWe minimize correction cycles by aligning plans with local code requirements.
- Specialized ADU engineering teamExperts in utility mapping, Title 24, load calculations, and site planning.
Our Features
Why Choose Cecilia Home?
Licensed, experienced, and trusted across California—we deliver precise designs, clear communication, and reliable results for every project.
PROFESSIONAL EXPERTISE
Licensed architects and engineers with deep knowledge of California codes, ensuring accurate, compliant, and build-ready designs.
CLIENT-CENTERED APPROACH
Clear communication and personalized guidance at every step, ensuring your vision stays at the center of the project.
COMPREHENSIVE SOLUTIONS
From design to permit approval, we provide complete, end-to-end services that save you time and streamline your project.
QUALITY ASSURANCE
All plans meet California building standards, with rigorous checks to ensure safety, accuracy, and long-term performance.
FAST & EFFICIENT DELIVERY
Our optimized design workflow allows us to deliver complete, permit-ready plans in as fast as 7 days—without compromising quality.
LOCAL EXPERIENCE
Expert understanding of California’s building styles, climate needs, and local city requirements for successful permits.
ADU Permit Ready
ADU Design & Engineering
California-compliant ADU drawings engineered for accuracy, safety, and easy permit approval.
Garage Conversion ADU
Transform your garage into a valuable living space with complete architectural and structural plans engineered for city approval.
Detached Backyard ADU
Custom ground-up ADU designs tailored to your property setbacks and zoning requirements for maximum privacy and value.
JADU & Interior Conversion
Convert existing bedrooms or spaces into independent Junior ADUs with efficiency and full code compliance.
Two-Story ADU Design
Maximize square footage with multi-level ADU designs engineered for structural stability and aesthetic appeal.
Our Process
Our Process
Our process is designed to be transparent and efficient, delivering a complete one-stop service from design to final permit approval.
Guidance for your project
Free Consultation
Expert advice on your project needs, budget considerations, and permit requirements.
On-Site Assessment
Precise measurements and site evaluation for accurate project planning.
Design Development
Creating detailed plans and visualizations to bring your vision alive.
Permit Acquisition
Navigating complex approval processes to ensure code-compliant construction.
Construction Support
Ongoing guidance and contractor coordination throughout the building process.
Client Testimonials
Trusted by California Homeowners
Ranked #1 on Thumbtack based on verified reviews from homeowners who relied on our architectural and structural engineering services.
Cecilia Home designed our complete home renovation, explained everything clearly, and delivered detailed plans. Honest, professional, and fairly priced—our HOA now knows exactly how to proceed.
View Verified ReviewTrudy M.
Home Remodeling
Mason delivered exactly what I needed—professional, responsive, and great value. Clear communication throughout the process. I'll rely on him for all future remodeling projects.
View Verified ReviewJoanne D.
Home Remodeling
Mason responded instantly and offered honest guidance on whether my garage conversion would pass city review. Knowledgeable, direct, and trustworthy—I look forward to working with them again.
View Verified ReviewJasper T.
ADU Design
I appreciated their honesty. They explained that my foundation cracks were common in the Bay Area and didn't push unnecessary work. Professional, transparent advice I could trust.
View Verified ReviewArturo S.
Structural Engineering
As a general contractor, I value teams who are responsive and accurate. Cecilia Home delivered clear communication, timely plans, and over-the-counter approval. I highly recommend them.
View Verified ReviewKevin V.
Building Permit Services
Mason gave detailed structural guidance for removing our load-bearing wall, including safety considerations. Quick responses and practical advice that helped us comply with local regulations.
View Verified ReviewJackson B.
Wall Removal
FAQ
Frequently Asked Questions
Find answers to common questions about ADU design, engineering, and permit approval.
Our ADU design package includes architectural plans, structural engineering drawings, load calculations, Title-24 energy compliance, site planning, and all documents required for city submittal. We provide a complete permit-ready plan set.
Initial concepts are typically ready within 5–7 days. Full architectural and structural plans take about 2–3 weeks depending on the complexity of your project.
City review times vary by jurisdiction, but most ADU permits take 4–8 weeks for first review. Our clear and code-compliant drawings help reduce corrections and speed up the approval process.
Yes. We prepare all required documents and submit the ADU plans to your city on your behalf. We also respond to correction notices until your permit is approved.
Yes. All ADUs—including conversions—require structural plans and calculations to meet California Building Code requirements. Our licensed engineers prepare full structural drawings for safe and buildable ADUs.
Absolutely. We specialize in garage conversions and prepare structural reinforcement details, updated layouts, and all required compliance documents for a smooth review process.