The Timeline of Building an ADU: What to Expect
Building an accessory dwelling unit (ADU) is one of the most rewarding ways to add space and value to your property. However, understanding the timeline helps set clear expectations and ensures a smooth experience. At MF ADU, we’ve refined a streamlined process that keeps projects efficient—whether you’re creating a rental unit, a guest suite, or extra family space.
Step 1: Initial Consultation and Planning
Every project starts with a conversation. During this stage, we evaluate your property, discuss your goals, and review zoning requirements. This step typically takes a few weeks, depending on site conditions and how quickly you finalize your design preferences.
Step 2: Design Development and Permitting
Once we’ve identified your vision, our design team creates detailed plans that meet both your needs and California’s building standards. We then submit them for city approval. Permitting timelines vary by location but usually take several weeks once the application is complete. Our team stays in touch with local agencies to keep things moving forward.
Step 3: Site Preparation and Foundation Work
After permits are approved, we begin preparing your site. This includes clearing the area, grading, and installing utilities. The foundation—whether a slab or pier system—is then built to support the structure. These steps can often happen while your prefabricated ADU is being built in the factory, saving significant time overall.
Step 4: Off-Site Fabrication and Delivery
Prefab ADUs are constructed in controlled environments, ensuring high quality and no weather-related delays. While this phase happens off-site, we stay in touch with you to provide updates. Once fabrication is complete, your ADU is delivered and ready for assembly on your property.
Step 5: Installation and Final Finishing
Assembly and installation usually take only a few days. Afterward, we handle the interior finishes—flooring, paint, fixtures, and final inspections. Once approved by the city, your ADU is ready for move-in or rental.
Did you know?
Did you know? Prefabricated ADUs can cut total project timelines by nearly half compared to traditional construction—saving months of waiting and on-site disruption.
A Streamlined Experience from Start to Finish
Building an ADU doesn’t have to take forever. At MF ADU, we manage the entire process—from planning and permitting to installation and final inspection—so you can enjoy your new space as soon as possible.
Explore our prefabricated ADU models and see how we make the building process simple, fast, and efficient.
Frequently Asked Questions
How long does it take to build an ADU from start to finish?
Most projects are completed within a few months, depending on design complexity, permitting, and site preparation.
Can construction and permitting happen at the same time?
Yes. We often prepare your site while permits are being reviewed to keep the project on schedule.
What factors can delay the process?
Delays may occur due to city reviews, weather conditions, or utility connections, but prefabrication minimizes these risks.
Do all ADU projects follow the same timeline?
Not exactly. Each city and property is unique, but the overall process follows the same basic steps.
When can I move into my ADU?
Once final inspections are complete and the city grants occupancy approval, your ADU is ready to use.