Montana State Building Code Governs Tiny House Construction

Title 50, Chapter 60 MCA establishes the Montana State Building Code, administered by the Department of Labor and Industry's Building and Measurement Standards Bureau. Montana has adopted IRC Appendix Q, which provides minimum standards for dwellings under 400 square feet on permanent foundations. Tiny houses on wheels meeting RVIA or NFPA 1192 standards are regulated as recreational vehicles, not dwellings, and cities cannot impose dwelling code requirements on them. Manufactured tiny homes fall under HUD-code rules at MCA 50-78. Local zoning still controls placement, lot size, and use.

Building or occupying a tiny home without proper permits, inspections, or code compliance may trigger stop-work orders, fines, and removal under MCA 50-60-107.