Historic Zoning Commission

Old North Knoxville H: Level II

4-D-23-HZ

Applicant Request

Proposed replacement of fifteen windows on the c.2005 rear addition. Existing windows are double-hung, one-over-one, wood windows. Proposed replacement windows are one-over-one, double-hung Ultrex (a pultruded fiberglass composite project manufactured by Marvin). The provided specs note the muntins and rails are 1-5/8", comparable to the current window.

APPROVED 4.20.2023, subject to one condition: 1) applicant to provide specifics for window replacements to staff for approval, including details on top and bottom rails, stiles, and meeting rail, to reflect wood window measurements.

Site Info

Two-story residence clad in brick and wood shingles, featuring a steeply-pitched slate hipped roof with multiple turrets, exterior brick chimneys, and a hipped-roof, one-story wrap-around porch.

1. 505 E. Scott Ave is a contributing resource to the ONK National Register Historic District and local overlay. The proposed scope of work will occur on a non-historic, flat-roof rear addition built c.2005.

2. The windows to be replaced are double-hung, one-over-one wood windows. According to a written description provided by the owner, after 18 years, the wood windows have severely deteriorated since installation, due to the quality of non-historic wood window materials and a high degree of sun exposure on the rear addition.

3. ONK's guidelines note that if replacement windows are necessary, they should be the same overall size as the originals, with the same pane division, material, and muntin depth, width, and profile. The applicant is not proposing to replace original windows on the house.

4. Some alternative materials have been considered by the HZC for windows on non-historic additions or new construction, including aluminum-clad wood. The Ultrex fiberglass product has not been evaluated. Fiberglass's tensile strength allows the muntins and meeting rails to be thinner in profile than vinyl or other composite products, which would require more surface area to support the glass panes.

5. A letter from the contractor notes the frame width of the window at 1-5/8", which is the same frame width as the current wood double-hung window. To confirm the proposed window replacement meeting all guidelines (same pane division and muntin depth, width, and profile) other than material, the applicant should provide specific measurements of stiles, top and bottom rails, and meeting rail to compare with the wood product.