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HomeMy WebLinkAbout11-03-25 Public Comment - E. Bonnett - UDC Draft_ Plate Height Measurement Language for Shed RoofsFrom:Erik Bonnett To:Bozeman Public Comment Subject:[EXTERNAL]UDC Draft: Plate Height Measurement Language for Shed Roofs Date:Monday, November 3, 2025 9:02:16 AM Attachments:image.png CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. Dear Community Development Board and Staff, Thank you for your continued work to serve our community, especially as it relates toupdating the zoning code. This comment follows up on a previous comment I submitted on July 3rd, 2025 entitled "Public Comment: New UDC Plate Height Definition." That comment illustrated with a letterand series of drawings how the draft UDC plate height measurement language would treat shed roof forms more restrictively than other forms, such as gable forms. This is because ashed roof form, also known as a mono-pitch, has a low and high side, so even on very small buildings like a garage ADU, a shed roof's high side would extend above the proposed plateheight maximum. The language as it currently stands would make shed roof forms essentially fully prohibited on the second story in R-A and the third story in R-B. The September 9th, 2025 draft of the UDC does not address this issue. The draft languageappears to be crafted with gable roof forms in mind. When a gable roof form rises away from a side property line, the draft language's limitations create a plane above the plate slopingaway from the property line. The draft language allows dormers above 50% of that plate length. When a gable end is adjacent to the side property line, a triangular wall area ispermitted to extend above the plate height limit. In both cases, the area between the plate height limit and the total building height limit may be partially obstructed by a vertical wall.Thus it is appropriate that shed roofs similarly be permitted to partially obstruct the above- plate-limit height. The following is specific amendment language intended to treat shed roof forms equitably togable forms. The unbolded text is the current draft language; the bold italic text is the language proposed to be added: Measurementa. Wall plate height is measured from grade to the wall plate of the building. b. Wall plate height is measured at the point where the exterior wall intersects the roofstructure, typically at the building corners. For complex roof forms - such as cross gables or standard gables - the measurement applies at the corners, and the roof form then extends abovethis height. For shed roofs, the measurement applies at the lowest two corners, and the roofform then extends above this height.c. Dormers located within the roof form above the wall plate cannot exceed more than 50% of the width of the roof.d. The high-side plate corners of a shed roof located within 15' of a property line cannot exceed by more than 6 feet the wall plate maximum height specified by zoning district. The loose hatch is the allowable building volume up to the plate height. The tight hatch is theobstructed area above the plate height allowed for various roof forms, including the shed roofarea proposed to be allowed 6' above the plate-height maximum on the shed's high side. The first two drawings above illustrate the current draft language for a gable end and dormercondition. Currently a gable end 5' from the property line can obstruct 50% of the planebetween the plate-height maximum and the total building height limit, with a mean height5'-3" above the plate height. A dormer could obstruct 37% of that same plane. Thus it isreasonable the high side of a shed roof should also be allowed to partially obstruct that plane(33% in R-A as proposed). A 6' encroachment above the plate height for shed roofs isappropriate because it is intuitively and numerically a similar obstruction as would be allowedfor gable roof forms, and because that would allow a 2:12 shed to slope for 36' beforeexceeding this height, which is adequate to facilitate a shed roof form on the top level of abuilding. The zoning code should not be a tool to dictate architectural style. The proposed languageabove equitably addresses the underlying issues of mass, bulk and shading across a propertyline, while giving designers, builders, and architects the latitude to select a style that fits theproject. Thank you for considering this recommendation to address the issue, Erik Bonnett Architect, AIA He, Him, His www.studioco-hab.com p. 651.336.0394