But no matter how decorative the patterning or how compelling the form, the roof is a highly vulnerable element of a shelter that will inevitably fail. A poor roof will permit the accelerated deterioration of historic building materials-- masonry, wood, plaster, paint--and will cause general disintegration of the basic structure. Furthermore, there is an urgency involved in repairing a leaky roof since such reThe essential ingredients for replacing and maintaining a historic roof are:
costs will quickly become prohibitive. Although such action is desirable as
soon as a failure is discovered, temporary patching methods should be carefully
chosen to prevent inadvertent damage to sound or historic roofing materials and
related features. Before any repair work is performed, the historic value of
the materials used on the roof should be understood. Then a complete internal
and external inspection of the roof should be planned to determine all the
causes of failure and to identify the alternatives for repair or replacement of
- Understanding the historic characterof the building and being sympathetic to it.
- Careful examination and recordingof the existing roof and any evidence of earlier roofs.
- Consideration of the historic craftsmanship and detailing and implementing them in the renewal wherever visible.
- Supervision of the roofersor maintenance personnel to assure preservation of historic fabric and proper understanding of the scope and detailing of the project.
- Consideration of alternative materialswhere the original cannot be used.
- Cyclical maintenance program to assure that the staff understands how to take care of the roof and of the particular trouble spots to safeguard.
Although a new roof can be an object of beauty, it will not be protective for long without proper maintenance. At least twice a year, the roof should be inspected against a checklist. All changes should be recorded and reported. Guidelines should be established for any foot traffic that may be required for the maintenance of the roof. Many roofing materials should not be walked on at all. For some--slate, asbestos, and clay tile--a self-supporting ladder might be hung over the ridge of the roof, or planks might be spanned across the roof surface. Such items should be specifically designed and kept in a storage space accessible to the roof. If exterior work ever requires hanging scaffolding, use caution to insure that the anchors do not penetrate, break, or wear the roofing surface, gutters, or flashing.