Detached accessory dwelling unit — Billings, MT
Last updated: September 24, 2026
What affects the price
Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.
About this service
A detached ADU is a standalone building separate from your main home, like a backyard cottage. These provide the most privacy for you or your tenants since there are no shared walls. You need this if you have a large enough yard to accommodate a separate structure.
Frequently asked in Billings
What are the options for accessory dwelling unit financing?
Are affordable ADUs possible in Billings?
What is the cost to build an accessory dwelling unit in Billings?
What does 'accessory dwelling unit' actually mean?
Can I find an accessory dwelling unit for rent in Billings?
What are the options for emergency ADU construction?
Who are the best accessory dwelling unit companies?
Also serving nearby: Salt Lake City · West Valley City · Sandy · West Jordan · Fort Collins
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Billings — population 120,864; about 2,652 residents per square mile across 45.6 sq mi. ZIP codes covered include 59101, 59102, 59103, 59104, 59105, 59106, 59107, 59108.
Neighborhoods served in Billings: North Park, South Park, West End, Heights, Downtown Billings — and every surrounding area.
Areas we serve
Browse by state, then city.