Commission reviews proposed changes to accessory building standards in Mapleton City Code

The Mapleton City Planning Commission reviewed proposed amendments to Mapleton City Code, Title 18, that would change standards for residential accessory buildings, including maximum rear-yard coverage and height/setback requirements.

Sean, a city staff member presenting the item, told the commission the city has seen a substantial increase in accessory buildings and that neighbors had expressed concerns about one recently built structure. "Our revised proposal would be to reduce the max rear yard coverage that you could have with accessory buildings from 30% to 20%," Sean said. He outlined additional changes: accessory buildings under 15 feet tall could remain as close as 3 feet to a side or rear property line (unchanged from current code); buildings 15 to 18 feet tall would be required to set back at least 10 feet from the rear property line; and for every 1 foot above 18 feet the building would need to be shifted an additional 2 feet from the rear property line until it reaches the standard rear setback (typically 25 feet in most zones). Sean gave an example: "If the building was 24 feet, you'd have to be 22 feet."

Commission members questioned the tradeoffs. One commissioner said reducing allowable footprint from 30% to 20% could create an incentive to build taller instead of using more ground area. "When you reduce the footprint size, you create incentive to go taller," the commissioner said. Sean replied that owners could still build taller but the taller structure would need to be shifted further into the property rather than closer to neighboring rear yards.

Commission members also discussed alternative approaches, including allowing 30% coverage if the structure were limited to a single story with a lower maximum height while reducing coverage for two-story accessory buildings. Staff noted prior proposals had included a 24-foot height limit, but that was revised downward following feedback; current discussion centers on the 18-foot threshold with the incremental setback formula above that height.

The commission did not record a formal vote on the ordinance in the transcript. Commissioners and staff indicated they would continue to refine the language and return the item for further consideration; one staff speaker said the item would likely return on May 7.

The discussion focused on balancing neighbor privacy and views with property-owner rights to construct accessory structures; the transcript records substantive technical clarifications from staff and several commissioners but no formal adoption at this meeting.