The windows on many historic buildings are an important aspect
of the architectural character of those buildings. Their design,
craftsmanship, or other qualities may make them worthy of preservation.
This is self-evident for ornamental windows, but it can be equally
true for warehouses or factories where the windows may be the
most dominant visual element of an otherwise plain building. Evaluating the significance of these windows and planning
for their repair or replacement can be a complex process involving
both objective and subjective considerations. The Secretary of
the Interior's Standards for Rehabilitation and the accompanying
guidelines, call for respecting the significance of original materials
and features, repairing and retaining them wherever possible,
and when necessary, replacing them in kind. This Brief is based
on the issues of significance and repair which are implicit in
the standards, but the primary emphasis is on the technical issues
of planning for the repair of windows including evaluation of
their physical condition, techniques of repair, and design considerations
when replacement is necessary.
Much of the technical section presents repair techniques as an
instructional guide for the do-it-yourselfer. The information will
be useful, however, for the architect, contractor, or developer
on large-scale projects. It presents a methodology for approaching
the evaluation and repair of existing windows, and considerations
for replacement, from which the professional can develop alternatives
and specify appropriate materials and procedures.
Evaluating the architectural or historical significance of windows
is the first step in planning for window treatments, and a general
understanding of the function and history of windows is vital
to making a proper evaluation. As a part of this evaluation, one
must consider four basic window functions: admitting light to
the interior spaces, providing fresh air and ventilation to the
interior, providing a visual link to the outside world, and enhancing
the appearance of a building. No single factor can be disregarded
when planning window treatments; for example, attempting to conserve
energy by closing up or reducing the size of window openings may
result in the use of more energy by increasing electric lighting
loads and decreasing passive solar heat gains.
 Windows are frequently important visual focal points, especially on simple facades such as this mill building. Replacement of the multi-pane windows with larger panes could dramatically alter the appearance of the building. Photo: NPS files. |
Historically, the first windows in early American houses were
casement windows; that is, they were hinged at the side and opened
outward. In the beginning of the eighteenth century single- and
double-hung windows were introduced. Subsequently many styles of
these vertical sliding sash windows have come to be associated
with specific building periods or architectural styles, and this
is an important consideration in determining the significance
of windows, especially on a local or regional basis. Site-specific,
regionally oriented architectural comparisons should be made to
determine the significance of windows in question. Although such
comparisons may focus on specific window types and their details,
the ultimate determination of significance should be made within
the context of the whole building, wherein the windows are one
architectural element.
After all of the factors have been evaluated, windows should be
considered significant to a building if they: 1) are original,
2) reflect the original design intent for the building, 3) reflect
period or regional styles or building practices, 4) reflect changes
to the building resulting from major periods or events, or 5)
are examples of exceptional craftsmanship or design. Once this
evaluation of significance has been completed, it is possible
to proceed with planning appropriate treatments, beginning with
an investigation of the physical condition of the windows.
"The Repair of Historic Wooden Windows" an Historic Preservation Brief
