ADU Locator

1 Best ADU Builders in Billings, Montana

Verified ADU contractors and builders in Billings, MT

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Larch Architecture

At Larch Architecture, we’re proud to be part of that solution by offering ready-to-build Accessory Dwelling Unit (ADU) plans—crafted specifically for life in Montana. We don’t just design for Montana—we live here.

(406) 698-0955
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Frequently Asked Questions — ADU Builders in Billings

How much does it cost to hire an ADU builder in Billings?

ADU construction costs in Billings, Montana vary widely depending on size, type, and site conditions. Detached ADUs typically range from $150,000–$400,000+, while garage conversions and attached ADUs can be more affordable. Contact multiple builders in Billings to get accurate quotes for your specific project.

How long does it take to build an ADU in Billings?

In Billings, the ADU construction timeline typically ranges from 6 to 18 months from permit application to move-in. Permitting alone can take 2–6 months depending on Montana local regulations. Prefab and modular ADUs often have faster timelines than site-built units.

Do I need a permit to build an ADU in Billings?

Yes, a building permit is required for ADU construction in Billings, Montana. Your ADU builder will typically handle the permit application as part of their service. Montana has adopted streamlined ADU permitting laws in recent years, which may reduce wait times.

What types of ADUs can be built in Billings?

Common ADU types in Billings include detached ADUs (backyard cottages), attached ADUs, garage conversions, basement conversions, and prefab/modular ADUs. The best type for your property depends on lot size, zoning, and budget. A local Billings ADU builder can advise on what's allowed on your specific parcel.