DS 20-259 (Dolores 3 NE 11th): Consideration of a Track 1 Design Study Referral (DS 20-259, Jackson) for the installation of a new roof on an existing residence located on Dolores Street, 3 NE of 11th Avenue in the Single-Family Residential (R-1) Zoning District. (APN 010-155-012)

CEQA Action: Staff recommends the project be found Categorically Exempt from CEQA pursuant to Section 15301 (Existing Facilities).

The applicant is requesting to install a new approximately 2,300 square foot metal roof on an existing single-family residence located on Dolores 3 SE 11th.

Adopt a Resolution (Attachment 1) approving a Track 1 Design Study Referral for the installation of a new low gloss dark bronze standing seam metal roof on an existing residence located on Dolores Street, 3 NE of 11th Avenue in the Single-Family Residential (R-1) Zoning District.

At the October 14, 2020 hearing, the Planning Commission considered a Design Study application for the installation of a new standing seam copper roof to an existing single-family residence to replace an existing wood shake roof.  The Commission continued the application with direction to the applicant to resubmit with a different roof material other than copper siting environmental concerns, potential impacts to neighbors, and the attractiveness of an artificial patina as areas of concern. Additionally, the Commission provided direction that if the alternative roof material is going to be metal, the project shall be brought back to the Planning Commission for consideration, but if the roof material is a more traditional material (i.e. composition shingle), the roof can be approved at the staff level.

The applicant is proposing to install an approximately 2,300 square foot standing seam metal roof on an existing single-family residence.  The proposed re-roof will maintain the existing roof pitch with no changes to the building form. The roof is proposed to be 24 gauge low gloss Dark Bronze CoolR by Sheffield Metals (refer to Attachments 2 & 3). A material sample will be made available at the project site on the day of the hearing.

Metal Roofs. While Residential Design Guideline 9.8 states, metal, plastic, and glass roofs are inappropriate in all neighborhoods, metal roofs are becoming more common due to the increased fire risk that the traditional wood shake roofs pose. Metal roofs approved by the Commission, regardless of material (aluminum, zinc, steel), are required to have a matte and non-reflective finish to minimize light and glare impacts to adjacent properties. 

The proposed metal roofing material (Dark Bronze CoolR by Sheffield Metals) is proposed to have a low gloss finish and a Solar Reflectance Index (SRI)* of 24. While the city has not established a prescriptive set of standards for relating to reflectivity indexes or values, the proposed material has an index lower than other approved metal roofs and is substantially similar in terms of appearance to other approved metal roofs. The manufacture only lists one product that references a matte appearance, “Matte Black” (refer to Attachment 3), however, it is unclear if the actual finish is matte or if it is just the name of the color.  Additionally, the Matte Black color has a higher SRI index (27) than the proposed Dark Bronze.

While Design Guideline 9.8 states, “Roof materials should be consistent with the architectural style of the building and with the context of the neighborhood," the commission did not comment as to the appropriateness of a metal roof based on the architecture at the previous hearing.  Rather the item was continued with direction to return if an alternative metal (other than copper) was proposed. Additionally, there are multiple residences with metal roofs in the immediate vicinity so the introduction of a metal roof would not be out of character for the neighborhood.  As such, staff is supportive of the proposed standing seam dark bronze copper roof.     

* Solar  Reflectance Index(SRI) is a measure of the constructed surface’s ability to stay cool in the sun by reflecting solar radiation and emitting thermal radiation. It is defined such that a standard black surface has an initial SRI of 0, and a standard white surface has an initial SRI of 100.

Light Reflectance Value (LRV) measures the amount of visible or usable light that reflects from a surface. LRV is expressed as a percentage from 0 to 100; the higher the number the more visible light that is reflected. Typically, lighter colors will have a higher value than dark colors, but texture can impact LRV as well.

Staff recommends that the proposed project be found categorically exempt from the California Environmental Quality Act (CEQA), State CEQA guidelines and local environmental regulations, pursuant to Section 15301 (Class 1) – Existing Facilities. Class 1 exemptions include minor alterations to private structures involving no expansion of the existing use. The project is a re-roof of an existing single family dwelling. The project does not present any unusual circumstances that would result in a potentially significant environmental impact.