HomeMy WebLinkAbout2011/07/19 Item 08 Attachment A Appendix_U_Preservation_Brief_09_Repair_Historic_Wooden_Windows
Preservation Brief 9: The Repair of Historic Wooden WindowsPage 1of 11
9
The Repair of
Historic Wooden Windows
John H. Myers
»Architectural or Historical Significance
»Physical Evaluation
»Repair Class I: Routine Maintenance
»Repair Class II: Stabilization
»Repair Class III: Splices and Parts Replacement
»Weatherization
»Window Replacement
»Conclusion
»Additional Reading
A NOTE TO OUR USERS: The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white, and
some complex charts have been omitted.
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.
Architectural or Historical Significance
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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.
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
Windows are frequently important visual
types and their details, the ultimate
focal points, especially on simple facades
such as this mill building. Replacement of
determination of significance should be made
the multi-pane windows with larger panes
within the context of the whole building,
could dramatically alter the appearance of
wherein the windows are one architectural
the building. Photo: NPS files.
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.
Physical Evaluation
The key to successful planning for window treatments is a careful evaluation of existing
physical conditions on a unit-by-unit basis. A graphic or photographic system may be
devised to record existing conditions and illustrate the scope of any necessary repairs.
Another effective tool is a window schedule which lists all of the parts of each window
unit. Spaces by each part allow notes on existing conditions and repair instructions.
When such a schedule is completed, it indicates the precise tasks to be performed in the
repair of each unit and becomes a part of the specifications. In any evaluation, one
should note at a minimum:
1) window location
2) condition of the paint
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3) condition of the frame and sill
4) condition of the sash (rails, stiles and muntins)
5) glazing problems
6) hardware, and
7) the overall condition of the window (excellent, fair, poor, and so forth)
Many factors such as poor design, moisture, vandalism, insect attack, and lack of
maintenance can contribute to window deterioration, but moisture is the primary
contributing factor in wooden window decay. All window units should be inspected to see
if water is entering around the edges of the frame and, if so, the joints or seams should
be caulked to eliminate this danger. The glazing putty should be checked for cracked,
loose, or missing sections which allow water to saturate the wood, especially at the
joints. The back putty on the interior side of the pane should also be inspected, because
it creates a seal which prevents condensation from running down into the joinery. The
sill should be examined to insure that it slopes downward away from the building and
allows water to drain off. In addition, it may be advisable to cut a dripline along the
underside of the sill. This almost invisible treatment will insure proper water runoff,
particularly if the bottom of the sill is flat. Any conditions, including poor original design,
which permit water to come in contact with the wood or to puddle on the sill must be
corrected as they contribute to deterioration of the window.
One clue to the location of areas of excessive
moisture is the condition of the paint; therefore,
each window should be examined for areas of
paint failure. Since excessive moisture is
detrimental to the paint bond, areas of paint
blistering, cracking, flaking, and peeling usually
identify points of water penetration, moisture
saturation, and potential deterioration. Failure of
the paint should not, however, be mistakenly
interpreted as a sign that the wood is in poor
condition and hence, irreparable. Wood is
frequently in sound physical condition beneath
Deterioration of poorly maintained windows
unsightly paint. After noting areas of paint
usually begins on horizontal surfaces and at
failure, the next step is to inspect the condition
joints, where water can collect and saturate
the wood. Photo: NPS files.
of the wood, particularly at the points identified
during the paint examination.
Each window should be examined for operational soundness beginning with the lower
portions of the frame and sash. Exterior rainwater and interior condensation can flow
downward along the window, entering and collecting at points where the flow is blocked.
The sill, joints between the sill and jamb, corners of the bottom rails and muntin joints
are typical points where water collects and deterioration begins. The operation of the
window (continuous opening and closing over the years and seasonal temperature
changes) weakens the joints, causing movement and slight separation. This process
makes the joints more vulnerable to water which is readily absorbed into the endgrain of
the wood. If severe deterioration exists in these areas, it will usually be apparent on
visual inspection, but other less severely deteriorated areas of the wood may be tested
by two traditional methods using a small ice pick.
An ice pick or an awl may be used to test wood for soundness. The technique is simply
to jab the pick into a wetted wood surface at an angle and pry up a small section of the
wood. Sound wood will separate in long fibrous splinters, but decayed wood will lift up in
short irregular pieces due to the breakdown of fiber strength.
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Another method of testing for soundness consists of pushing a sharp object into the
wood, perpendicular to the surface. If deterioration has begun from the hidden side of a
member and the core is badly decayed, the visible surface may appear to be sound
wood. Pressure on the probe can force it through an apparently sound skin to penetrate
deeply into decayed wood. This technique is especially useful for checking sills where
visual access to the underside is restricted.
Following the inspection and analysis of the results, the scope of the necessary repairs
will be evident and a plan for the rehabilitation can be formulated. Generally the actions
necessary to return a window to "like new" condition will fall into three broad categories:
1) routine maintenance procedures,2) structural stabilization, and 3) parts
replacement. These categories will be discussed in the following sections and will be
referred to respectively as Repair Class I,Repair Class II, and Repair Class III.
Each successive repair class represents an increasing level of difficulty, expense, and
work time. Note that most of the points mentioned in Repair Class I are routine
maintenance items and should be provided in a regular maintenance program for any
building. The neglect of these routine items can contribute to many common window
problems.
Before undertaking any of the repairs mentioned in the following sections all sources of
moisture penetration should be identified and eliminated, and all existing decay fungi
destroyed in order to arrest the deterioration process. Many commercially available
fungicides and wood preservatives are toxic, so it is extremely important to follow the
manufacturer's recommendations for application, and store all chemical materials away
from children and animals. After fungicidal and preservative treatment the windows may
be stabilized, retained, and restored with every expectation for a long service life.
Repair Class I: Routine Maintenance
Repairs to wooden windows are usually labor intensive and
relatively uncomplicated. On small scale projects this
allows the do-it-yourselfer to save money by repairing all
or part of the windows. On larger projects it presents the
opportunity for time and money which might otherwise be
spent on the removal and replacement of existing windows,
to be spent on repairs, subsequently saving all or part of
the material cost of new window units. Regardless of the
actual costs, or who performs the work, the evaluation
process described earlier will provide the knowledge from
which to specify an appropriate work program, establish
the work element priorities, and identify the level of skill
needed by the labor force.
This historic double-hung
The routine maintenance required
window has many layers of
to upgrade a window to "like new"
paint, some cracked and
condition normally includes the missing putty, slight separation
at the joints, broken sash
following steps: 1) some degree of
cords, and one cracked pane.
interior and exterior paint
Photo: NPS files.
removal, 2) removal and repair of
sash (including reglazing where necessary), 3) repairs to the
frame, 4) weatherstripping and reinstallation of the sash, and
5) repainting. These operations are illustrated for a typical
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double-hung wooden window, but they may be adapted to
other window types and styles as applicable.
Historic windows have usually acquired many layers of paint
over time. Removal of excess layers or peeling and flaking
paint will facilitate operation of the window and restore the
clarity of the original detailing. Some degree of paint removal is
also necessary as a first step in the proper surface preparation
for subsequent refinishing (if paint color analysis is desired, it
should be conducted prior to the onset of the paint removal).
There are several safe and effective techniques for removing
paint from wood, depending on the amount of paint to be
removed.
After removing paint from
Paint removal should
the seam between the
begin on the interior
interior stop and the
frames, being careful
jamb, the stop can be
pried out and gradually
to remove the paint
worked loose using a pair
from the interior stop
of putty knives as shown.
and the parting bead,
Photo: NPS files.
particularly along the
seam where these stops meet the jamb. This
can be accomplished by running a utility knife
along the length of the seam, breaking the
paint bond. It will then be much easier to
Sash can be removed and repaired in a
remove the stop, the parting bead and the
convenient work area. Paint is being removed
from this sash with a hot air gun. Photo: NPS
sash. The interior stop may be initially loosened
files.
from the sash side to avoid visible scarring of
the wood and then gradually pried loose using a pair of putty knives, working up and
down the stop in small increments. With the stop removed, the lower or interior sash
may be withdrawn. The sash cords should be detached from the sides of the sash and
their ends may be pinned with a nail or tied in a knot to prevent them from falling into
the weight pocket.
Removal of the upper sash on double-hung units is similar but the parting bead which
holds it in place is set into a groove in the center of the stile and is thinner and more
delicate than the interior stop. After removing any paint along the seam, the parting
bead should be carefully pried out and worked free in the same manner as the interior
stop. The upper sash can be removed in the same manner as the lower one and both
sash taken to a convenient work area (in order to remove the sash the interior stop and
parting bead need only be removed from one side of the window). Window openings can
be covered with polyethylene sheets or plywood sheathing while the sash are out for
repair.
The sash can be stripped of paint using appropriate techniques, but if any heat
treatment is used, the glass should be removed or protected from the sudden
temperature change which can cause breakage. An overlay of aluminum foil on gypsum
board or asbestos can protect the glass from such rapid temperature change. It is
important to protect the glass because it may be historic and often adds character to the
window. Deteriorated putty should be removed manually, taking care not to damage the
wood along the rabbet. If the glass is to be removed, the glazing points which hold the
glass in place can be extracted and the panes numbered and removed for cleaning and
reuse in the same openings. With the glass panes out, the remaining putty can be
removed and the sash can be sanded, patched, and primed with a preservative primer.
Hardened putty in the rabbets may be softened by heating with a soldering iron at the
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point of removal. Putty remaining on the glass may be softened by soaking the panes in
linseed oil, and then removed with less risk of breaking the glass. Before reinstalling the
glass, a bead of glazing compound or linseed oil putty should be laid around the rabbet
to cushion and seal the glass. Glazing compound should only be used on wood which has
been brushed with linseed oil and primed with an oil based primer or paint. The pane is
then pressed into place and the glazing points are pushed into the wood around the
perimeter of the pane.
The final glazing compound or putty is applied and beveled to complete the seal. The
sash can be refinished as desired on the inside and painted on the outside as soon as a
"skin" has formed on the putty, usually in 2 or 3 days. Exterior paint should cover the
beveled glazing compound or putty and lap over onto the glass slightly to complete a
weather-tight seal. After the proper curing times have elapsed for paint and putty, the
sash will be ready for reinstallation.
While the sash are out of the frame, the condition of the wood in the jamb and sill can
be evaluated. Repair and refinishing of the frame may proceed concurrently with repairs
to the sash, taking advantage of the curing times for the paints and putty used on the
sash. One of the most common work items is the replacement of the sash cords with
new rope cords or with chains. The weight pocket is frequently accessible through a door
on the face of the frame near the sill, but if no door exists, the trim on the interior face
may be removed for access. Sash weights may be increased for easier window operation
by elderly or handicapped persons. Additional repairs to the frame and sash may include
consolidation or replacement of deteriorated wood. Techniques for these repairs are
discussed in the following sections.
The operations just discussed summarize the efforts necessary to
restore a window with minor deterioration to "like new" condition.
The techniques can be applied by an unskilled person with
minimal training and experience. To demonstrate the practicality
of this approach, and photograph it, a Technical Preservation
Services staff member repaired a wooden double-hung, two over
two window which had been in service over ninety years. The
wood was structurally sound but the window had one broken
pane, many layers of paint, broken sash cords and inadequate,
worn-out weatherstripping. The staff member found that the
frame could be stripped of paint and the sash removed quite
easily. Paint, putty and glass removal required about one hour for
each sash, and the reglazing of both sash was accomplished in
about one hour. Weatherstripping of the sash and frame,
replacement of the sash cords and reinstallation of the sash,
Following the
relatively simple parting bead, and stop required an hour and a half. These times
repairs, the window is
refer only to individual operations; the entire process took several
weathertight, like new
days due to the drying and curing times for putty, primer, and
in appearance, and
serviceable for many paint, however, work on other window units could have been in
years to come.Photo:
progress during these lag times.
NPS files.
Repair Class II: Stabilization
The preceding description of a window repair job focused on a unit which was
operationally sound. Many windows will show some additional degree of physical
deterioration, especially in the vulnerable areas mentioned earlier, but even badly
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damaged windows can be repaired using simple processes. Partially decayed wood can
be waterproofed, patched, built-up, or consolidated and then painted to achieve a sound
condition, good appearance, and greatly extended life. Three techniques for repairing
partially decayed or weathered wood are discussed in this section, and all three can be
accomplished using products available at most hardware stores.
One established technique for repairing wood which is split, checked or shows signs of
rot, is to: 1) dry the wood, 2) treat decayed areas with a fungicide, 3) waterproof with
two or three applications of boiled linseed oil (applications every 24 hours), 4) fill cracks
and holes with putty, and 5) after a "skin" forms on the putty, paint the surface. Care
should be taken with the use of fungicide which is toxic. Follow the manufacturers'
directions and use only on areas which will be painted. When using any technique of
building up or patching a flat surface, the finished surface should be sloped slightly to
carry water away from the window and not allow it to puddle. Caulking of the joints
between the sill and the jamb will help reduce further water penetration.
When sills or other members exhibit surface
weathering they may also be built-up using wood
putties or homemade mixtures such as sawdust
and resorcinol glue, or whiting and varnish. These
mixtures can be built up in successive layers, then
sanded, primed, and painted. The same caution
about proper slope for flat surfaces applies to this
technique.
Wood may also be strengthened and stabilized by
consolidation, using semirigid epoxies which
saturate the porous decayed wood and then
This illustrates a two-part expoxy
patching compound used to fill the
harden. The surface of the consolidated wood can
surface of a weathered sill and rebuild
then be filled with a semirigid epoxy patching
the missing edge. When the epoxy
compound, sanded and painted. Epoxy patching
cures, it can be sanded smooth and
painted to achieve a durable and
compounds can be used to build up missing
waterproof repair. Photo: NPS files.
sections or decayed ends of members. Profiles can
be duplicated using hand molds, which are created
by pressing a ball of patching compound over a sound section of the profile which has
been rubbed with butcher's wax. This can be a very efficient technique where there are
many typical repairs to be done. The process has been widely used and proven in
marine applications; and proprietary products are available at hardware and marine
supply stores. Although epoxy materials may be comparatively expensive, they hold the
promise of being among the most durable and long lasting materials available for wood
repair. More information on epoxies can be found in the publication "Epoxies for Wood
Repairs in Historic Buildings," cited in the bibliography.
Any of the three techniques discussed can stabilize and restore the appearance of the
window unit. There are times, however, when the degree of deterioration is so advanced
that stabilization is impractical, and the only way to retain some of the original fabric is
to replace damaged parts.
Repair Class III: Splices and Parts Replacement
When parts of the frame or sash are so badly deteriorated that they cannot be stabilized
there are methods which permit the retention of some of the existing or original fabric.
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These methods involve replacing the deteriorated parts with new matching pieces, or
splicing new wood into existing members. The techniques require more skill and are
more expensive than any of the previously discussed alternatives. It is necessary to
remove the sash and/or the affected parts of the frame and have a carpenter or
woodworking mill reproduce the damaged or missing parts. Most millwork firms can
duplicate parts, such as muntins, bottom rails, or sills, which can then be incorporated
into the existing window, but it may be necessary to shop around because there are
several factors controlling the practicality of this approach. Some woodworking mills do
not like to repair old sash because nails or other foreign objects in the sash can damage
expensive knives (which cost far more than their profits on small repair jobs); others do
not have cutting knives to duplicate muntin profiles. Some firms prefer to concentrate on
larger jobs with more profit potential, and some may not have a craftsman who can
duplicate the parts. A little searching should locate a firm which will do the job, and at a
reasonable price. If such a firm does not exist locally, there are firms which undertake
this kind of repair and ship nationwide. It is possible, however, for the advanced do-it-
yourselfer or craftsman with a table saw to duplicate moulding profiles using techniques
discussed by Gordie Whittington in "Simplified Methods for Reproducing Wood
Mouldings," Bulletin of the Association for Preservation Technology, Vol. III, No. 4, 1971,
or illustrated more recently in The Old House, Time-Life Books, Alexandria, Virginia,
1979.
The repairs discussed in this section involve window frames which may be in very
deteriorated condition, possibly requiring removal; therefore, caution is in order. The
actual construction of wooden window frames and sash is not complicated. Pegged
mortise and tenon units can be disassembled easily, if the units are out of the building.
The installation or connection of some frames to the surrounding structure, especially
masonry walls, can complicate the work immeasurably, and may even require
dismantling of the wall. It may be useful, therefore, to take the following approach to
frame repair: 1) conduct regular maintenance of sound frames to achieve the longest
life possible, 2) make necessary repairs in place, wherever possible, using stabilization
and splicing techniques, and 3) if removal is necessary, thoroughly investigate the
structural detailing and seek appropriate professional consultation.
Another alternative may be considered if parts replacement is required, and that is sash
replacement. If extensive replacement of parts is necessary and the job becomes
prohibitively expensive it may be more practical to purchase new sash which can be
installed into the existing frames. Such sash are available as exact custom
reproductions, reasonable facsimiles (custom windows with similar profiles), and
contemporary wooden sash which are similar in appearance. There are companies which
still manufacture high quality wooden sash which would duplicate most historic sash. A
few calls to local building suppliers may provide a source of appropriate replacement
sash, but if not, check with local historical associations, the state historic preservation
office, or preservation related magazines and supply catalogs for information.
If a rehabilitation project has a large number of windows such as a commercial building
or an industrial complex, there may be less of a problem arriving at a solution. Once the
evaluation of the windows is completed and the scope of the work is known, there may
be a potential economy of scale. Woodworking mills may be interested in the work from
a large project; new sash in volume may be considerably less expensive per unit; crews
can be assembled and trained on site to perform all of the window repairs; and a few
extensive repairs can be absorbed (without undue burden) into the total budget for a
large number of sound windows. While it may be expensive for the average historic
home owner to pay seventy dollars or more for a mill to grind a custom knife to
duplicate four or five bad muntins, that cost becomes negligible on large commercial
projects which may have several hundred windows.
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Most windows should not require the extensive repairs discussed in this section. The
ones which do are usually in buildings which have been abandoned for long periods or
have totally lacked maintenance for years. It is necessary to thoroughly investigate the
alternatives for windows which do require extensive repairs to arrive at a solution which
retains historic significance and is also economically feasible. Even for projects requiring
repairs identified in this section, if the percentage of parts replacement per window is
low, or the number of windows requiring repair is small, repair can still be a cost
effective solution.
Weatherization
A window which is repaired should be made as energy efficient as possible by the use of
appropriate weatherstripping to reduce air infiltration. A wide variety of products are
available to assist in this task. Felt may be fastened to the top, bottom, and meeting
rails, but may have the disadvantage of absorbing and holding moisture, particularly at
the bottom rail. Rolled vinyl strips may also be tacked into place in appropriate locations
to reduce infiltration. Metal strips or new plastic spring strips may be used on the rails
and, if space permits, in the channels between the sash and jamb. Weatherstripping is a
historic treatment, but old weatherstripping (felt) is not likely to perform very
satisfactorily. Appropriate contemporary weatherstripping should be considered an
integral part of the repair process for windows. The use of sash locks installed on the
meeting rail will insure that the sash are kept tightly closed so that the weatherstripping
will function more effectively to reduce infiltration. Although such locks will not always
be historically accurate, they will usually be viewed as an acceptable contemporary
modification in the interest of improved thermal performance.
Many styles of storm windows are available to improve the thermal performance of
existing windows. The use of exterior storm windows should be investigated whenever
feasible because they are thermally efficient, cost-effective, reversible, and allow the
retention of original windows (see "Preservation Briefs: 3"). Storm window frames may
be made of wood, aluminum, vinyl, or plastic; however, the use of unfinished aluminum
storms should be avoided. The visual impact of storms may be minimized by selecting
colors which match existing trim color. Arched top storms are available for windows with
special shapes. Although interior storm windows appear to offer an attractive option for
achieving double glazing with minimal visual impact, the potential for damaging
condensation problems must be addressed. Moisture which becomes trapped between
the layers of glazing can condense on the colder, outer prime window, potentially
leading to deterioration. The correct approach to using interior storms is to create a seal
on the interior storm while allowing some ventilation around the prime window. In actual
practice, the creation of such a durable, airtight seal is difficult.
Window Replacement
Although the retention of original or existing windows is always desirable and this Brief
is intended to encourage that goal, there is a point when the condition of a window may
clearly indicate replacement. The decision process for selecting replacement windows
should not begin with a survey of contemporary window products which are available as
replacements, but should begin with a look at the windows which are being replaced.
Attempt to understand the contribution of the window(s) to the appearance of the
facade including: 1) the pattern of the openings and their size; 2) proportions of the
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frame and sash; 3) configuration of window panes; 4)muntin profiles; 5) type of wood;
6) paint color; 7) characteristics of the glass; and 8) associated details such as arched
tops, hoods, or other decorative elements. Develop an understanding of how the window
reflects the period, style, or regional characteristics of the building, or represents
technological development.
Armed with an awareness of the significance of the existing window, begin to search for
a replacement which retains as much of the character of the historic window as possible.
There are many sources of suitable new windows. Continue looking until an acceptable
replacement can be found. Check building supply firms, local woodworking mills,
carpenters, preservation oriented magazines, or catalogs or suppliers of old building
materials, for product information. Local historical associations and state historic
preservation offices may be good sources of information on products which have been
used successfully in preservation projects.
Consider energy efficiency as one of the factors for replacements, but do not let it
dominate the issue. Energy conservation is no excuse for the wholesale destruction of
historic windows which can be made thermally efficient by historically and aesthetically
acceptable means. In fact, a historic wooden window with a high quality storm window
added should thermally outperform a new double-glazed metal window which does not
have thermal breaks (insulation between the inner and outer frames intended to break
the path of heat flow). This occurs because the wood has far better insulating value than
the metal, and in addition many historic windows have high ratios of wood to glass, thus
reducing the area of highest heat transfer. One measure of heat transfer is the U-value,
the number of Btu's per hour transferred through a square foot of material. When
comparing thermal performance, the lower the U-value the better the performance.
According to ASHRAE 1977 Fundamentals, the U-values for single glazed wooden
windows range from 0.88 to 0.99. The addition of a storm window should reduce these
figures to a range of 0.44 to 0.49. A non-thermal break, double-glazed metal window
has a U-value of about 0.6.
Conclusion
Technical Preservation Services recommends the retention and repair of original
windows whenever possible. We believe that the repair and weatherization of existing
wooden windows is more practical than most people realize, and that many windows are
unfortunately replaced because of a lack of awareness of techniques for evaluation,
repair, and weatherization. Wooden windows which are repaired and properly
maintained will have greatly extended service lives while contributing to the historic
character of the building. Thus, an important element of a building's significance will
have been preserved for the future.
Additional Reading
ASHRAE Handbook 1977 Fundamentals. New York: American Society of Heating,
Refrigerating and Air-conditioning Engineers, 1978 (chapter 26).
Ferro, Maximillian. Preservation: Present Pathway to Fall River's Future. Fall River,
Massachusetts: City of Fall River, 1979 (chapter 7).
file://H:\Gabriel\Historic Preservation DRAFT\Appendices\Preservation Brief 9 The Rep...05/11/2011
Preservation Brief 9: The Repair of Historic Wooden WindowsPage 11of 11
"Fixing Double-hung Windows." Old House Journal (no. 12, 1979): 135.
Morrison, Hugh. Early American Architecture. New York: Oxford University Press, 1952.
Phillips, Morgan, and Selwyn, Judith. Epoxies for Wood Repairs in Historic Buildings.
Washington, DC: Technical Preservation Services, U.S. Department of the Interior
(Government Printing Office, Stock No. 024016000951), 1978.
Rehab Right. Oakland, California: City of Oakland Planning Department, 1978 (pp.
7883).
"Sealing Leaky Windows." Old House Journal (no. 1, 1973): 5.
Smith, Baird M. "Preservation Briefs: 3 Conserving Energy in Historic Buildings."
Washington, DC: Technical Preservation Services, U.S. Department of the Interior, 1978.
Weeks, Kay D. and David W. Look, "Preservation Briefs: 10 Exterior Paint Problems on
Historic Woodwork." Washington, DC: Technical Preservation Services, U.S. Department
of the Interior, 1982.
Washington, D.C. 1981
Home page logo: Historic six-over-six windows--preserved. Photo: NPS files.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
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