How Long Does It Take to Build an ADU?

The timeline for building a backyard home varies depending on the builder, type of construction, and scope of work. Here we'll share the overall average project time for building a prefab accessory dwelling unit (ADU) with Villa. We'll also share the main stages of our process and timelines for each.

Building timeline overview

Our ADU builds take about eleven months on average, from the signing of the Project Services Agreement to final inspection. It depends on your ADU and the design choices you make. We can provide a more accurate estimate upfront because all of our backyard home models are prefab, meaning there's very little construction guesswork. Compare this with stick-build projects, which are subject to all kinds of unpredictable delays, such as due to bad weather. Plus, because we're an all-in-one builder, meaning we handle everything from permits to installation, we've streamlined the entire process.

1. Assessment and design (1 month)

You'll start with a free instant quote to see if we can build one of our many ADU models on your property and get a ballpark estimate for budget. If you'd like to proceed from there, we'll create a custom proposal. This proposal includes a timeline, budget, and site plan.

2. Permitting (2 to 4 months)

After you've finalized your design decisions, such as any layout customizations and upgrades, our team will work on permitting. This includes permit research and facilitation as well as payments to local and state agencies. Our experts have worked on hundreds of projects and have access to pre-approved designs so that you can trust we'll get your permit approved.

3. Manufacturing and site prep (4 to 12 months)

After the permits have been secured and you've signed off on your final project, we'll prepare your site. This involves clearing dirt and obstructions, plus excavating for the stem wall foundation's footings and piers. Then we'll install the foundation. While this is happening, we'll with our factory partners to manufacture your home to your exact specifications offsite.

4. Installation and finishing (2 weeks to 2 months)

When your ADU arrives from the factory, our team will install it. This includes hooking up electrical, water, and sewer lines with up to 50 feet of trenching. It also includes seaming if your model comes in two sections. (Seaming involves using interlocking siding to make the unit look like a unified whole.) Keep in mind that installing a prefab home means you'll have less construction noise and disruption than you'd have with site-built construction.

Then our team will do a final inspection, and you can move in!