Including gutters, downspouts, leaderheads, flashing and other roof details
The different building types in the historic districts have a large assortment of roof designs. Among the most common are gable ended (front or side), hipped, shed and low pitched or "flat" roofs. It is important in contemplating work on an existing roof to retain important visual clues to a building's style and age. In addition to the shape of a roof, other aspects of the construction such as the roofing material, flashing, ridge caps or cresting, gutters, downspouts, flashing, skylights, chimneys, lightning rods and ventilators communicate information regarding the age and style of a building as well as add visual interest. This section will review the types of work that are approvable on roofs and associated details on rated structures under the jurisdiction of the Commissions.
Shape.
The Commissions discourage the alteration of the general shape of a sloped roof on any rated structure under their jurisdiction. All alterations to roof shape including the addition of dormers (where no evidence remains that one existed previously) must be referred to the Architectural Review Committee and the Commission for approval.
Minor alterations to the pitch of "flat" roofs can be approved at the staff level if the change does not have a major impact on the appearance of the building. Changes in the shape of roofs of unrated structures can also be approved at the staff level if they do not cause a negative impact on the general appearance of the building.
Roofing Material.
A wide variety of roofing materials are used in the local historic districts. Slate is the most common original roofing material for structures built before and through the first decade of the 20th century. Cement-asbestos roofing material became common for new roofs and replacement roofs in the late 19th century. There are also examples of clay tile and metal roofs in all of the districts. These roofs are commonly referred to as "hard" roofs because they are very resistant to weathering and fire.
The Commissions encourage the retention of "hard" roofs (slate, cement asbestos, metal) wherever they exist, and can be reasonably retained. The staff of the Commissions have the authority to allow the removal of a "hard" roof on all but blue and purple-rated structures. A statement from a licensed roofing contractor must be submitted with the application to document the extent of the failure of the roof. The staff of the Commissions will investigate to verify the information supplied in the contractor's report. A replacement roof can be a "soft" roofing material such as asphalt shingles or a fiberglass reinforced shingle. The Commissions require that the roof color be black or dark gray. Samples of the type of roofing material must be submitted with the application for the approval of the staff. Other roofing material may be applied for. Depending on the age of the building, roofs may be approved by the staff or referred to the Commissions for their review.
The Commissions reserve the right to approve the removal of an original "hard" roof from all blue or purple-rated structures. Of particular importance to the Commissions is the existence of colored or shaped patterned slate roofs typical of some early 19th century cottages and late 19th century Second Empire style buildings. Examples of these patterned roofs are rare and every effort should be made to insure their preservation. The staff of the Commissions may review and approve all work on existing "soft" roofs and roofs on unrated structures so long as they conform to the above stated policy.
Flashing, Downspouts, Gutters and Leaderheads.
These elements are as important to the waterproofing function of a roof as the roofing material. Copper and galvanized metal are the most common materials used for flashing, downspouts, gutters, and leaderheads. As with the shape and type of roofing material, the shape of the gutters and to a lesser extent the downspouts communicate a great deal of information about the age and style of the building. When not properly maintained, the loss or failure of any one of these building parts can quickly undermine the effectiveness of an otherwise serviceable roof in protecting the fabric of a building.
The Commissions retain the right to approve any change in the style, size, material or configuration of the gutters, downspouts, flashing, or leaderheads on a blue or purple-rated structure. Applications for work which match the original in all aspects may be approved at the staff level. On green, red, or gold-rated buildings, the Commissions have given the staff the authority to issue Certificates of Appropriateness for replacement gutters, downspouts and flashing so long as they are similar in style and dimension to the originals. On unrated structures any work is approvable at the staff level. The staff will investigate the proposed work to insure that it will not detract from the character of the historic district.
Special note regarding the support and attachment of gutters to a structure: Care should be taken to observe and reproduce any special molding, strap or bracket used to support or attach a gutter or downspout to a building. This is particularly important in late 19th century structures where a decorative molding in concert with the gutter section often forms an important element of the cornice section.
Skylights.
Skylight installations should be handled with care and attention to their effect on the appearance of the roof, the roof structure and the compatibility of materials. They should relate primarily to the historic appropriateness of their use and only secondarily to the contemporary needs of the present occupants.
Skylights may be appropriate on original warehouses and some commercial structures. Skylights are occasionally appropriate on townhouse structures, Creole cottages, Victorian shotguns, and other residential building types where dormers do not already exist.
Plans for skylight installation shall meet the following criteria: 1. All applications shall include information regarding the size, location and design of the proposed skylight; 2. On blue and purple-rated structures the Commissions retain the right to review and approve all applications for installation of skylights, except where they previously existed. The Commissions discourage the addition of highly visible skylights on blue-rated structures and prohibit them on purple-rated structures; 3. The staff may review and approve the installation of minimally visible skylights on green, red and gold-rated structures; 4. If more than one skylight is proposed, the total number should be kept to a minimum. The openings should be arranged on the roof in orderly fashion. The construction detail for the installation of the skylight should keep to a minimum the alterations to the existing structure. Generally speaking, the long axis of the skylight should be parallel to the rafters; 5. Skylights shall not be placed on roof slopes with dormers.
Dormers.
Dormers add to the function of the roof level of a building and to the visual interest of a historic structure. The Commissions strongly encourage the retention of existing original dormers on all rated structures. The Commissions also encourage the reconstruction of dormers on buildings where there is clear evidence that they existed previously.
Evidence may be supplied either through photographs of the building which show the dormer in place or from existing framing in the roof. Where existing physical evidence is used as evidence of a previously existing dormer or where a photograph does not show adequate detail of the appearance of the dormer, the Commissions encourage the use of comparison to existing buildings and historic documents to formulate a proposal for the design of the dormer. Examples of dormers of similar age and style are studied to assist in making drawings for the new dormer. Care should be taken to observe the location on the roof, spacing, dimension, and detailing of historical examples. With proper documentation, including elevation and detail drawings, the staff is empowered by the Commissions to approve the addition of a dormer to an existing rated building.
For the addition of a dormer to a "rated" structure where no evidence remains of the previous existence of a dormer, the work must be approved by the Architectural Review Committee and the Commission. Drawings showing the proposal in elevation, with details, must be submitted with the work application. The Commissions encourage additions of this type to be appropriate to the style and age of the building.
Chimneys.
In addition to adding visual interest to the roof of a building, the size and placement of chimneys help describe the interior arrangement of rooms. Chimneys can also convey clues about the age and style of a building through the use of decorative brick work and ceramic chimney pots.
The Commissions strongly encourage the retention of visually prominent chimneys on all rated structures under their jurisdiction. The removal of an original chimney from a purple or bluerated structure must be approved by the Architectural Review Committee or the Commission. On green, red or gold-rated buildings, the removal of an original chimney can be approved at the staff level if it can be demonstrated that it is in poor structural condition. The Commissions encourage the repair of structurally deficient chimneys whenever possible. Non-original chimneys, which do not contribute to the architectural or historical value of a building, can be removed with the approval of the staff.
The Commissions encourage the reconstruction of chimneys which have been removed from a building. As with dormers, photographs or physical evidence can be used to establish the previous existence of a chimney. Where accurate evidence does not exist of the details of the chimney's original appearance, reconstruction is allowed if there exists adequate chimney comparisons from other buildings or historic documents. The staff is empowered by the Commissions to approve (based on elevation and detail drawings) the reconstruction of a previously existing chimney where the material matches the original.
New chimneys to vent fireplaces which did not previously exist or reconstruction of previously existing chimneys in non-original materials may be expressed in light weight materials. A flue surround may be constructed with a stucco exterior finish provided that it meets all other fire code requirements. For rated structures, the Commissions discourage the construction of flue enclosures with non-traditional materials such as weather boards. The addition of a new chimney on blue and purple-rated structures is discouraged and must be approved by the full Commission. New chimneys which are not visually prominent may be approved by the staff on buildings with lower architectural ratings.
Ridge Caps, Cresting, Lightning Rods, and Ventilators.
The roofs of historic structures often carried various equipment to assist in the maintenance or function of a building. The Commissions encourage the retention of all existing original roof equipment, including but not limited to ceramic ridge caps, ceramic or cast iron cresting, lightning rods, and metal ventilators.
Applications for the removal of these items must be reviewed by the Commissions for all purple and blue-rated structures. On lower rated structures the staff may approve the removal if it is considered appropriate. Where some question exists as to the appropriateness of a removal, the staff will refer the matter to the Architectural Review Committee. The conditions for the addition of these items are the same as for their removal.
Modern Mechanical Equipment and Roof Penetrations.
The contemporary use of a historical building often requires the placement of mechanical equipment on the roof. Various types of penetrations are also often required for vents and ducts. The placement of equipment on roofs and penetrations for vents and ducts requires the approval of the Commissions before work can go forward. The Commissions encourage a minimum amount of visual clutter on the roof of a building. The placement of air conditioning compressor units on the roofs of structures, where they are visible from the street, is not allowed. Applications for mechanical equipment and penetrations must be approved by the Commissions on all purple and blue-rated structures. The Commissions have directed the staff to handle approvals for all buildings of lesser architectural importance.