Fort Collins, CO Accessory Structures: Tiny Homes (2026)

City Code Sec. 5-30, the amendments and deletions to the 2024 International Residential Code, lists among its numbered amendments that Appendix BB Tiny Houses is adopted in its entirety, right alongside Appendix BA Manufactured Housing Used as Dwellings, also adopted whole, and Appendix BC Accessory Dwelling Units, adopted with local amendments. Adopting Appendix BB in full means tiny houses built to that appendix's reduced ceiling height, loft, ladder, and egress standards can obtain a building permit in Fort Collins as tiny houses rather than needing to meet the full-size dwelling provisions of the base residential code.

Placement of a tiny house as an accessory dwelling unit still runs through the separately amended Appendix BC, which caps ADUs at one per lot, requires the ADU to be secondary in size and function to the primary dwelling, and requires compliance with the Land Use Code's dimensional standards for where an ADU can sit on the lot; a detached ADU's location must also meet Section R302 fire-separation requirements. Because Appendix BB is a building-code appendix, it governs construction standards for the structure itself, such as reduced stair and loft dimensions, while the Land Use Code separately controls whether and where a tiny house can be sited on a given lot, including as a principal or accessory use. CDNS handles the building permit and inspection under the adopted Appendix BB standards for any tiny house project in the city.