Historic Zoning Commission

Edgewood-Park City H-1: Level II

9-E-12-HZ

Applicant Request

Level II. Replacement/repair

Replace original slate roofing with metal faux slate roofing. Fabricate custom ridge caps that will replicate the plain (not embossed) metal ridge caps that are currently on the house. The new ones will be solid gray in color. The original finials will be returned to their original positions and better secured. Replace guttering.

Site Info

Two-story frame with weatherboard wallcovering, fishscale shingles in gables, sawn wood brackets in eaves. Hip roof with lower cross-gables, slate covering, finials. Two-story wrap-around porch with with mansard roof with standing seam metal covering.

The applicant's contractor asserts that the ~ 120 yr-old slate roof has reached the end of its use life and needs to be replaced because the slates are very brittle and pieces are delaminating, breaking off, and falling . The applicant asserts that the charcoal gray color with enhanced dimensional shading is very close in color to the current slate. The applicant asserts that their insurance company would not cover the cost of slate replacement.

STAFF FINDINGS-- Part I (removal of slate rather than repair)
1) Excerpt from Preservation Brief 29, Technical Preservation Services, National Park Service, DOI, 1992: "The relatively large percentage of historic buildings roofed with slate during the late nineteenth and early twentieth centuries means that many slate roofs, and the 60 to 125 year life span of the slates most commonly used, may be nearing the end of their serviceable lives at the end of the twentieth century." (Jeffrey S. Levine, The Repair, Replacement & Maintenance of Historic Slate Roofs)

2) Slate samples from and observaion of the current slate roof covering indicate some degree of deterioration.

3) The metal ridge caps that are currently on the house show signs of rust.

4) The Edgewood-Park City recommend to applicants to "try to repair or reuse such materials as slate and tile when they are available."

STAFF FINDINGS -- Part II (use of an alternate material to replace the slate)
1) The Park-City Edgewood Design Guidelines allow for substitute roofing materials when the original material is not readily available or when it is "cost is prohibitive."

2) The applicant asserts that their contractor provided information that similar slate roof shingles were not readily available.

3) In a recent slate re-roofing application, there was a waiting period for slate to be mined from quarries.

4) Slate tile substitute materials are available in clay, polymer, resin as well as metal. There are at least two instances in which "rubber" substitute slate material that has been utilized in other areas is exhibiting curling at the edges.

STAFF FINDINGS -- Part III (replacement with decorative metal shingles)
1) The current slate roofing was original to the house and was/is still found on several George Barber houses in Knoxville historic districts.

2) There are at least two other remaining slate roofs shingles on Queen Anne houses (thought to be Barber Houses) on Washington Street.

3) The slate roof covering and finials are identified in the 1986 survey as a character-defining feature of the house. The front porch and new rear addition have non-historic standing seam metal roofing.

4) In Knoxville's historic districts, the most typical evolution from more expensive roofing materials has been to change to modern asphalt shingles as a lesser expensive material.

5) Standing seam sheet metal roofing was and is still utilized for roofing in this district and other Knoxville historic districts, so there is no doubt that this type of metal was historically and is currently utlized; however, the aesthetic and patterning of standing seam metal roof is different from that of the feaux metal-shingles.

6) Excerpt from "Roofing for Historic Buildings." National Park Service Preservation, Technical Preservation Services, Brief No 4, by Sarah M. Sweetser, 1978:
"In a rehabilitation project, there may be valid reasons for replacing the roof with a material other than the original. The historic roofing may no longer be available, or the cost of obtaining specially fabricated materials may be prohibitive. . . But if the roof is readily visible, the alternative material should match as closely as possible the scale, texture, and coloration of the historic roofing material."


EDGEWOOD-PARK CITY DESIGN GUIDELINES

ROOFS pp. 14-15
A roof is one of the most dominant features of a building. . . The houses in the Edgewood-Park City Historic District may have been roofed with slate, tile, wood shingles, metal, or with asphalt shingles, sometimes cut in over-size, shaped patterns. The modern building materials that are available may limit a property owner's access to roofing materials, but it is important that owners try to repair or reuse such materials as slate and tile when they are available. Printed and sculptured fiberglass shingles can also be used to duplicate the look of original roofs. If replacement materials are not available or are prohibitively expensive, intact historic roofing materials should be used on the visible elevations, with replacement materials used at the rear or on a less visible section of the roof.

The architectural features associated with a roof should be saved. These include attic vent windows, finials, roof cresting, molding, dormer windows, complex slopes and intersecting gables. If built-in gutters are present on the house, they should be repaired so that the original appearance of the roof is recaptured.

Although the historic zoning commission does not regulate colors, it is suggested that roof colors, which will
be visible for the lifetime of the roof, be dark in color to mimic the roof colors that were present when the buildings were new.

1) . . .Replacement roofs must copy the shape and pitch of original roofs, and the soffit, fascia and trim detail between roof and wall should mimic the original.

3.) Repair or replace roof details (chimneys, roof cresting, finials, attic vent windows, molding and
other unique roof features). Use some of these details in designing new buildings.

4.) Materials used in roofing existing buildings or new construction shall duplicate original roofing
materials as much as possible. Asphalt or fiberglass shingles can be appropriate, as are slate, standing
seam metal, or metal or wood shingle roof coverings. The color of roofing materials should be a
dark green, charcoal gray or black or dark reddish brown, to simulate the original roof colors.


SECRETARY OF INTERIORS STANDARDSparticularly applicable to this proposal:

2. The historic character of a property shall be retained and preserved. The removal of historic materials or alteration of features and spaces that characterize a property shall be avoided.

5. Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a property shall be preserved.

6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials. Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence.


FURTHER STAFF RECOMMENDATIONS for approving this application:

If the desire of the Edgewood-Park City Historic District is to support the use of alternative or simulated materials to allude to the original material or design in that district, then a precedent is set for slate roofing materials, only, due to the expense of slate shingles, rather than setting the precedent for all building materials. (Although the HZC reviews each application on a case-by-case basis and on the merits of each distinct and unique case, they are still bound to treat similarly situated properties similarly.) The basis for approval of replacing the slate shingles with the specifically proposed feaux slate metal shingles should be that the neighborhood and HZC find that the feaux metal slate shingles selected adequately simulates the original natural slate shingles.