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.
