Identify, Retain and Preserve
Identifying, retaining, and preserving windows--and
their functional and decorative features--from the restoration
period. Such features can include frames, sash, muntins,
glazing, sills, heads, hoodmolds, panelled or decorated
jambs and moldings, and interior and exterior shutters
The Ephrata Cloister, founded in 1732 by German settlers, is located in Central Pennsylvania's Lancaster
County. One of America's earliest religious communities, its twelve buildings are
open to the public and interpreted. The distinctive multi-paned
windows shown here from the interior (see photo, right) are part of the visitor's experience
at this National Historic Landmark site. Photo left: Courtesy, Pennsylvania
Historical and Museum Commission; Photo right:
Conducting an indepth survey of the condition of
existing windows from the restoration period early in
the planning process so that repair and upgrading methods
and possible replacement options can be fully explored.
Altering windows or window features from the restoration
Failing to properly document window features from the
restoration period which may result in their loss.Applying
paint or other coatings to window features or removing
them if such treatments cannot be documented to the
Changing the type or color of protective surface coatings
on window features unless the work can be substantiated
by historical documentation.
Stripping windows of sound material such as wood, cast
iron, and bronze.
Replacing windows from the restoration period solely
because of peeling paint, broken glass, stuck sash,
and high air infiltration. These conditions, in themselves,
are no indication that windows are beyond repair.
Protect and Maintain
Protecting and maintaining the wood and architectural
metals from the restoration period which comprise the
window frame, sash, muntins, and surrounds through appropriate
surface treatments such as cleaning, rust removal, limited
paint removal, and re-application of protective coating
In spite of the fact that this historic window is 250 years old, routine maintenance
of the paint coupled with glazing putty repairs
have kept the sash in operable condition over the years. Photo:
© John Leeke.
Making windows weathertight by re-caulking, and
replacing or installing weatherstripping. These actions
also improve thermal efficiency.
Evaluating the existing condition of materials to
determine whether more than protection and maintenance
are required, i.e. if repairs to windows and window
features will be required
Failing to provide adequate protection of materials
on a cyclical basis so that deterioration of the window
Retrofitting or replacing windows from the restoration
period rather than maintaining the sash, frame, and
Failing to undertake adequate measures to assure the
protection of window materials from the restoration
Repairing window frames and sash from the restoration
period by patching, splicing, consolidating or otherwise
reinforcing. Such repair may also include replacement
in kind--or with compatible substitute material--of
those extensively deteriorated or missing parts when
there are surviving prototypes such as architraves,
hoodmolds, sash, sills, and interior or exterior shutters
and blinds. The new work should be unobtrusively dated
to guide future research and treatment.
Original leaded glass windows are repairable, even though they may be damaged. Disassembling the window glass in warm water helps to soften the putty,
minimize breakage, and reduce exposure to airborne
dust. Photo: Neal A. Vogel.
Replacing an entire window from the restoration period
when repair of materials and limited replacement of
deteriorated or missing parts are appropriate.
Failing to reuse serviceable window hardware such as
brass sash lifts and sash locks.
Using a substitute material for the replacement part
that does not convey the visual appearance of the surviving
parts of the window or that is physically or chemically
Replacing in kind a window feature from the restoration
period that is too deteriorated to repair using the
same sash and pane configuration and other design details.
If using the same kind of material is not technically
or economically feasible when replacing windows deteriorated
beyond repair, then a compatible substitute material
may be considered. The new work should be unobtrusively
dated to guide future research and treatment.
Using the same sash and pane details in restoration
is key to achieving a
successful window project. Photo: NPS files.
Removing a window feature from the restoration period
that is unrepairable and not replacing it; or failing
to document the new work.
The following Restoration
work is highlighted to indicate that it involves
the removal or alteration of existing historic
windows and windows features that would be retained
in Preservation and Rehabilitation treatments;
and the replacement of missing window features
from the restoration period using all new materials.
Removing Existing Features from Other Historic
Removing or altering windows or window features
from other historic periods, such as later single-pane
glazing or inappropriate shutters.
Documenting materials and features dating
from other periods prior to their alteration or
removal. If possible, selected examples of these
features or materials should be stored to facilitate
Failing to remove a window feature from another
period, thus confusing the depiction of the building's
Failing to document window features from other
historic periods that are removed from the building
so that a valuable portion of the historic record
Re-creating Missing Features
from the Restoration Period
Re-creating a missing window or window feature
that existed during the restoration period based
on physical or documentary evidence; for example,
duplicating a hoodmold or shutter.
Constructing a window feature that was part of
the original design for the building, but was
never actually built; or constructing a feature
which was thought to have existed during the restoration
period, but for which there is insufficient documentation.