Introduction
The Secretary of the Interior's "Standards for Rehabilitation"
require that where historic windows are individually significant
features, or where they contribute to the character of significant
facades, their distinguishing visual qualities must not be destroyed.
Further, the rehabilitation guidelines recommend against changing
the historic appearance of windows through the use of inappropriate
designs, materials, finishes, or colors which radically change
the sash, depth of reveal, and muntin configuration; the reflectivity
and color of the glazing; or the appearance of the frame.
Windows are among the most vulnerable features of historic buildings
undergoing rehabilitation. This is especially the case with rolled
steel windows, which are often mistakenly not deemed worthy of
preservation in the conversion of old buildings to new uses. The
ease with which they can be replaced and the mistaken assumption
that they cannot be made energy efficient except at great expense
are factors that typically lead to the decision to remove them.
Maintaining historic steel windows for continued use is always recommended. Photo: NPS files. |
In many cases, however, repair and retrofit of the historic windows
are more economical than wholesale replacement, and all too often,
replacement units are unlike the originals in design and appearance.
If the windows are important in establishing the historic character
of the building, insensitively designed replacement
windows may diminish--or destroy--the building's historic character.
This Brief identifies various types of historic steel windows
that dominated the metal window market from 1890-1950. It then
gives criteria for evaluating deterioration and for determining
appropriate treatment, ranging from routine maintenance and weatherization
to extensive repairs, so that replacement may be avoided where
possible.(1) This information applies to do-it-yourself jobs and
to large rehabilitations where the volume of work warrants the
removal of all window units for complete overhaul by professional
contractors.
This Brief is not intended to promote the repair of ferrous metal
windows in every case, but rather to insure that preservation
is always the first consideration in a rehabilitation project.
Some windows are not important elements in defining a building's
historic character; others are highly significant, but so deteriorated
that repair is infeasible. In such cases, the Brief offers guidance
in evaluating appropriate replacement windows.
"The Repair and Thermal Upgrading of Historic Steel Windows" an Historic Preservation Brief
