Can you build a PSL Modular unit in Montana?

Yes. SB 528, effective January 1, 2024, requires every Montana municipality to allow at least one ADU by right on a lot with a single-family dwelling — attached, detached, or internal. A detached ADU is capped at the lesser of 1,000 sq ft or 75% of the primary home's floor area. The Montana Supreme Court allowed the law to take effect while related litigation continues, so confirm your city's adopted regulations but rely on the statewide floor.

The Montana Department of Labor & Industry, Building Codes Program (Business Standards Division), through its Factory-Built Building program. Units must bear a Montana Factory-Built Building Insignia (or, where applicable, the insignia of a reciprocal state or a certified third-party inspection agency) before sale. Your local jurisdiction then permits the site work — foundation, utilities, zoning — without re-reviewing the structure.

Cold and snow. Montana winters drive a high-performance thermal envelope and heavy ground-snow loads, especially in the mountains and the Flathead. Western Montana also sits in the Intermountain seismic belt (near Helena and toward Yellowstone), so seismic design matters there. PSL Modular engineers the cold-climate envelope, snow load, and seismic from your site.

Very. Gateway communities draw heavy tourism, and modular places finished cabins quickly through a short build season — the units are built indoors year-round and set fast. The building clears via the state insignia; your work is county land-use, septic, access, and any local short-term-rental rules.

They implement the state ADU floor and may add reasonable local standards (size, height, setbacks, parking). Both are high-demand, high-cost markets where a rentable ADU is compelling. Confirm the current local ordinance, but they can't ban the ADU outright under SB 528.