City Council Study Session Agenda and Packet 2022 11 07

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SUBJECT: STUDY SESSION — ACCESSORY DWELLING UNITS DATE: NOVEMBER 7, 2022 PAGE 3 OF 8 Size limitation on ADUs: ADU standards most often include a limitation on the size of the unit. This policy helps to ensure that the predominate character of the neighborhood remains as a single- family and helps to limit occupant density. The size limitation may be a cap on sq. ft. of building area or a limit as a percentage of principal dwelling area, and often will differ for attached and detached accessory units. The regulations on size from neighboring communities range from 550-1,200 sq. ft. and 1/3 to 1/2 of the principal dwelling size. Location of ADU on the lot: Attached ADUs may be integrated into the existing home (e.g. in the basement or separate floor of the home) or if attached to the principal dwelling most regulations require that they are constructed off the rear or side and behind the front facade of the principal dwelling. Regulations may also require that detached ADUs be set back behind the front facade of the principal dwelling and have minimum separation requirements from the principal dwelling. As with the other design and size restrictions, this type of policy helps to ensure preservation the character of the neighborhood as predominately single-family. Design Standards for ADUs: Design standards are also common in ADU ordinances to ensure the preservation of neighborhood character. These regulations may include standards for matching or compatible building materials, limitation on the massing and height of the ADU, window design and privacy standards, provision of outdoor use areas, and building setback and lot coverage maximums. Other common requirements include having the entry to the ADU on the side or rear or to be designed to be clearly subordinate to the entrance of the primary structure and having the ADU setback a minimum of 10 feet from the front of the principal dwelling facade. The images below provide examples of ADUs designs that have compatible materials and architecture with the principal dwelling. Example ADUs with compatible architecture and materials in relation to the principal dwelling � � 4 . c. s w ,. Spacing or limitation on number of ADUs within a neighborhood: Some communities may chose to limit the number or density of ADUs within particular zone districts or neighborhoods. This is often done by requiring a minimum spacing between properties with ADUs or a maximum perecent of properties within a certain radius containing ADUs. The City of Boulder provides an example of limiting the CITY COUNCIL COMMUNICATION 9