Identify, Retain and Preserve
Identifying, retaining, and preserving windows--and
their functional and decorative features--that are important
in defining the overall historic character of the building.
Such features can include frames, sash, muntins, glazing,
sills, heads, hoodmolds, panelled or decorated jambs
and moldings, and interior and exterior shutters and
blinds.
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This view of a historic building shows how the
windows clearly help define its character, partly
because of their shape and rhythm. If additional
windows were inserted in the gap of the upper
floors, the character would be drastically changed,
as would painting the window heads to match the
color of the brick walls.
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Conducting an indepth survey of the condition of
existing windows early in rehabilitation planning so
that repair and upgrading methods and possible replacement
options can be fully explored.
Removing or radically changing windows which are important
in defining the historic character of the building so
that, as a result, the character is diminished.
Changing the number, location, size or glazing pattern
of windows, through cutting new openings, blocking-in
windows, and installing replacement sash that do not
fit the historic window opening.
Changing the historic appearance of windows through
the use of inappropriate designs, materials, finishes,
or colors which noticeably change the sash, depth of
reveal, and muntin configuration; the reflectivity and
color of the glazing; or the appearance of the frame.
Obscuring historic window trim with metal or other
material.
Stripping windows of historic material such as wood,
cast iron, and bronze.
Replacing windows 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.
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The historic steel sash has been removed and replaced with modern aluminum sash, resulting in
a negative visual impact on the building's historic
character. Photo: NPS files.
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Protect and Maintain
Protecting and maintaining the wood and architectural
metals 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 systems.
Making windows weathertight by re-caulking and replacing
or installing weatherstripping. These actions also improve
thermal efficiency.
Evaluating the overall 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
results.
Retrofitting or replacing windows rather than maintaining
the sash, frame, and glazing.
Failing to undertake adequate measures to assure the
protection of historic windows.
Repair
Repairing window frames and sash by patching, splicing,
consolidating or otherwise reinforcing. Such repair
may also include replacement in kind--or with compatible
substitute material--of those parts that are either
extensively deteriorated or are missing when there are
surviving prototypes such as architraves, hoodmolds,
sash, sills, and interior or exterior shutters and blinds.
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These historic steel windows are being prepared
for repairs and re-finishing as part of a rehabilitation
project. Photo: NPS files.
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Replacing an entire window 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 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
incompatible.
Replace
Replacing in kind an entire window 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.
Removing a character-defining window that is unrepairable
and blocking it in; or replacing it with a new window
that does not convey the same visual appearance.
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Inappropriate change to a historic building means
the loss of its distinctive visual qualities,
as well as a lessening of its long-term historical
and cultural value. Photo: Martha L. Werenfels,
AIA.
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The following work
is highlighted to indicate that it represents
the particularly complex technical or design aspects
of Rehabilitation projects and should only be
considered after the preservation concerns listed
above have been addressed.
Design for the Replacement of Missing Historic
Features
Designing and installing new windows when the
historic windows (frames, sash and glazing) are
completely missing. The replacement windows may
be an accurate restoration using historical, pictorial,
and physical documentation; or be a new design
that is compatible with the window openings and
the historic character of the building.
Creating a false historical appearance because
the replaced window is based on insufficient historical,
pictorial, and physical documentation.
Introducing a new design that is incompatible
with the historic character of the building.
The following work is
highlighted to indicate that it represents the
particularly complex technical or design aspects
of Rehabilitation projects and should only be
considered after the preservation concerns listed
above have been addressed.
Alterations/Additions for the New Use
Designing and installing additional windows
on rear or other-non character-defining elevations
if required by the new use. New window openings
may also be cut into exposed party walls. Such
design should be compatible with the overall design
of the building, but not duplicate the fenestration
pattern and detailing of a character-defining
elevation.
Providing a setback in the design of dropped
ceilings when they are required for the new use
to allow for the full height of the window openings.
Installing new windows, including frames, sash,
and muntin configuration that are incompatible
with the building's historic appearance or obscure,
damage, or destroy character-defining features.
Inserting new floors or furred-down ceilings
which cut across the glazed areas of windows so
that the exterior form and appearance of the windows
are changed.
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In the rehabilitation of a church for offices and
apartments, the large open interior space was inappropriately subdivided by inserting a full second floor. Removing the stained glass windows further
changed the historic appearance, compromising their size and proportion on the interior. Photo: NPS files.
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