In most historic buildings, the window sash, window framing, and the architectural detail surrounding them were all carefully designed to harmonize withthe style, scale, and character of the building.
It is important, therefore, to retain the original window configuration, including the size of openings, sills,lintels, decorative wood or masonry moldings, as well as the sashes themselves.
Replacing sashes and frames is often unnecessary, because in many cases existing historic windows can be repaired. If it is necessary to replace or alter any window elements, such changes must be made according to the Commission’s Window Rules.
The historic and architectural character of a building can be seriously damaged by inappropriate window treatments.
The deterioration of historic windows is caused by age, weathering, and inade-quate maintenance. Such deterioration makes window operation impossible or inefficient, and diminishes energy performance. Because it is desirable to maintain the original materials in historic buildings, the installation of new window sashes and frames is appropriate only when the windows are in such
poor condition that replacement is required.
Deteriorated wood windows can often be restored in a cost-effective manner by treatment with preservatives, wood fillers and epoxies,
and by replacement of only severely damaged sections.
Broken, sticky, or loose sashes can be removed from the frames for repair, excess paint can be stripped from the sash and tracks, and weather stripping installed.
Repairing and preserving historic windows rather than replacing them is strongly encouraged, and will save original material while saving money.