Attached ADU Builders in Northern California
Add smart, livable space to your home with a custom attached ADU. Sidex designs and builds seamless additions that feel like they’ve always been part of your home.
4.9/5 rating from 56+ online reviews.
What Is an Attached ADU & Why It Works
An attached ADU is a self-contained living unit built as an extension of your existing home. Unlike detached units, an ADU attached to a house shares at least one wall with the main structure, making it a more cost-effective and space-efficient option.
Across attached ADU projects, homeowners are choosing this approach because it blends naturally with the home, simplifies utility connections, and often moves faster through approvals. At Sidex, we make sure your attached dwelling unit is designed right, built right, and fully compliant.
Complete Attached ADU Services
Custom Attached ADU Design
We design attached ADUs that integrate perfectly with your home’s layout and architecture. From private entrances to efficient floor plans, every detail is planned to maximize comfort, privacy, and functionality.
Full Attached ADU Construction
Our team handles complete attached ADU construction; from foundation extensions to framing, electrical, plumbing, and interior finishes. We build spaces that feel like a natural part of your home, not an add-on.
Permits & Code Compliance
Building an attached ADU California requires meeting local zoning and building codes. We manage permits, approvals, and inspections so your project moves forward without unnecessary delays.
Built with Precision, Designed for Real Living
Explore our projects to see how we build functional, durable, and visually seamless structures across Northern California.
How We Build Your Attached ADU
Consultation & Assessment
We evaluate your home’s layout, available space, and goals to determine the best approach for your attached ADU.
Step 1
Design & Planning
Our team creates a custom plan for your attached accessory dwelling unit, including layout, materials, and utility integration. We also handle permit documentation.
Step 2
Construction & Integration
We carefully build and connect the ADU attached to the house, ensuring structural integrity, proper insulation, and seamless transitions between old and new spaces.
Step 3
Final Walkthrough
We complete inspections, ensure everything meets code, and walk you through your new attached dwelling unit so it’s ready for use.
Step 4
Attached ADU Construction Across Northern California
We design and build attached ADUs for homeowners throughout the region, serving over 57 locations.
The Bay Area
From San Francisco to San Jose, we create space-efficient attached dwelling units that increase property value without sacrificing design.
South Lake Tahoe
We build durable attached ADUs designed for colder climates, with proper insulation and weather-resistant construction.
Sacramento Region
In Sacramento and surrounding areas, we deliver practical and cost-effective attached accessory dwelling unit solutions for growing households and rental income.
Attached ADU FAQs
What is an attached ADU?
An attached ADU is a separate living unit connected to your main home, with its own entrance, kitchen, and bathroom.
Is an attached ADU cheaper than a detached ADU?
In many cases, yes. Because it shares a structure and utilities, an attached ADU can be more cost-effective to build.
Can I rent out my attached ADU?
Yes, many homeowners use attached ADUs as rental units, depending on local regulations.
Do attached ADUs require permits in California?
Yes. Every attached ADU California project must comply with zoning laws and building codes. We handle the process for you.
Will it look like an addition or part of my home?
When designed properly, an attached accessory dwelling unit blends seamlessly with your existing structure.
Trustindex verifies that the original source of the review is Google.
Elizabeth Neilsen2024-07-15We needed some deck repairs and had Sidex out to give us a bid and suggestions. Best choice ever. They spent time to evaluate necessary repairs and gave us estimates. Contracted for the work. Workers were great. Very efficient and tidy. So happy with the results. Thank you Sidex. ❤️Trustindex verifies that the original source of the review is Google.Sruthi gn2024-06-15Thank you Sidex for an excellent work. They built our 12x12 deck in one day. Such a great team. We enjoyed the work .Trustindex verifies that the original source of the review is Google.Joshua K2024-06-02I recently had my dock replaced by Sidex Siding and Decking, and we couldn't be happier with how it turned out! I reached out to Andrey, and he and his team did an amazing job from start to finish. They listened to our vision for the dock, sourced high-quality materials, and maintained excellent communication throughout the process. The entire project was completed within a week, and the workmanship is outstanding. We are thrilled with how it turned out and would highly recommend Sidex Siding and Decking to anyone. Thank you, Andrey and team, for your exceptional work!Trustindex verifies that the original source of the review is Google.Rand Martin2024-05-16Excellent and meticulous work.Trustindex verifies that the original source of the review is Google.Barry Cohen2024-05-14Andrey and his team repaired a fence for me recently and I could not be happier with the work. I know he went out of his way to keep on schedule to do that work on the day upon which we agreed even though it was inconvenient for him. The team arrived on time, did the work efficiently and I believe for a reasonable price. The end product, the repair, was excellent. I would use this company again.Trustindex verifies that the original source of the review is Google.Nicole2024-05-13I am ???? grateful for this wheelchair ramp. They worked so hard to get it done in one day, so I could take my brother to the doctor by myself without using medical transportation. This is the first company that heard my needs and made it happen. I recommend Andrey! They are gentle, kind, and professional. Outstanding!Trustindex verifies that the original source of the review is Google.Elisey Borisov2024-05-09Thank you Sidex. Great team, easy to work with. Customer service was outstanding, answered all of my questions quickly, made me feel comfortable throughout all stages of the process. Great job guys, with new windows and siding my house looks brand new!Trustindex verifies that the original source of the review is Google.Any Way Moving2024-05-09I recently had the pleasure of hiring Sidex for siding installation on my home, and I couldn't be more impressed with the results. From start to finish, the entire process was seamless and professional. Firstly, the team at Sidex demonstrated excellent communication skills, promptly addressing all my inquiries and concerns. They provided a detailed quote outlining the scope of work and timeline for completion, which was very helpful in setting expectations. When it came to the installation itself, the craftsmanship exhibited by the crew was outstanding. They worked diligently, paying close attention to detail to ensure a flawless finish. The siding not only looks beautiful but also feels sturdy and durable, providing added protection to my home. Moreover, the project was completed within the agreed-upon timeframe, without any delays or unexpected issues. The crew was respectful of my property, keeping the work area clean and tidy throughout the process. Overall, I am beyond satisfied with the quality of work delivered by Sidex. Their expertise, professionalism, and attention to detail have truly transformed the exterior of my home. I would highly recommend their services to anyone in need of siding installation or any other home improvement projects.Trustindex verifies that the original source of the review is Google.Ariel Hernandez2024-05-09Absolutely killed it! From our first interaction, and up to the final moments of the project they showed true professionalism and good quality work with a smile on their face! I couldn’t recommend a better company, thank you!Trustindex verifies that the original source of the review is Google.Angel Solis2024-05-09Trusted company. Whatever your needs maybe be, regarding siding and decking, be sure that you can you trust Sidex.
