How to Save Historic Windows on an Existing Property

Along with bringing natural light into a home, windows also act as the building’s eyes, allowing the residents to look out into the world. Because of this important role they hold in the history of a house, many homeowners choose to preserve the original windows while creating a modern, updated home around them.
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Windows are one of the most expressive elements of a building’s facade, and when the originals are still intact in an older building, most restoration experts recommend a wide range of window repair options before resorting to completely replacing them as a last resort.

A renovation of a historic brownstone in New York City included the restoration of the existing two-over-two, double-hung windows and their interior folding wood shutters to their original appearance.

A renovation of a historic brownstone in New York City included the restoration of the existing two-over-two, double-hung windows and their interior folding wood shutters to their original appearance.

You may be thinking that the older the window, the draftier and less energy-efficient it is. However, it's possible to have your cake and eat it too: you can enjoy original windows and stay warm in winter months—and remain cool in the summer—with a few easy fixes.

Weatherstripping

Installing weatherstripping between the two sashes can reduce cold air infiltration from outside. Weatherstripping can be applied along the edges of any window (or door), and are an inexpensive way to reduce noise and draft from coming in. 

Weatherstripping on existing windows can make a world of difference in terms of air that can infiltrate through the gaps between window sashes, window frames, and open channels for window hardware.

Weatherstripping on existing windows can make a world of difference in terms of air that can infiltrate through the gaps between window sashes, window frames, and open channels for window hardware.

Window Inserts

Another solution—albeit more visible—is to install window inserts. Window inserts are acrylic windows that fit inside existing windows, acting almost as interior storm windows. They may change the interior profile of the trim, but can be easily uninstalled during the summer months if desired, and they don't affect the exterior appearance of the windows.

Arched windows are a unique architectural feature of this building, but on the interior, the window frames are rectangular and sealed with weatherstripping to reduce air infiltration from outside.

Arched windows are a unique architectural feature of this building, but on the interior, the window frames are rectangular and sealed with weatherstripping to reduce air infiltration from outside.

Storm Windows

On the other hand, exterior storm windows are another common and very effective option—because of the airspace between the two panes of glass. They can even outperform a new double-glazed metal window. Old doesn't have to mean inefficient.

 Storm windows, while never invisible, can have a reduced appearance if painted to match the existing window frames and if designed to fit flush, rather than protruding out from the facade.

 Storm windows, while never invisible, can have a reduced appearance if painted to match the existing window frames and if designed to fit flush, rather than protruding out from the facade.

Dealing With Damage to the Wood Framing

Another common issue with older windows is damage to wood framing members that can occur from rot or termites. While these problems will most likely require removal of some original material, it doesn’t mean that you need to replace an entire window. Partial replacement of wood members is always an option.

A house in Portland, Oregon, keeps its double-hung windows well-maintained with regular coats of dark, contrasting paint.

A house in Portland, Oregon, keeps its double-hung windows well-maintained with regular coats of dark, contrasting paint.

Preserve the Original Wood Whenever Possible

Generally speaking, it’s best to try and keep as much of the old wood as possible, since old-growth lumber—i.e. lumber manufactured prior to World War II—is more resistant to rot than the lumber that's found on the market today. So, be sparing in your operation. It's also nice to try and keep as much historic fabric as possible for history's sake.

The Torroja pendant light by David Weeks hangs in the dining area, standing in sharp relief to the home’s original brick, now painted white (in Benjamin Moore Paper White) along with the wooden floorboards (in Benjamin Moore Revere Pewter). Radiant heat underfoot means a toasty interior even without a surfeit of textiles. 

The Torroja pendant light by David Weeks hangs in the dining area, standing in sharp relief to the home’s original brick, now painted white (in Benjamin Moore Paper White) along with the wooden floorboards (in Benjamin Moore Revere Pewter). Radiant heat underfoot means a toasty interior even without a surfeit of textiles. 

Dealing With Broken Window Panes

A similar approach of selective removal and replacement can be applied to original or historic windows that have broken window panes. Individual panes can be easily cut to size and inserted into existing window sashes or muntins by removing old putty or caulk, inserting the new panes, and re-puttying or caulking.

A brownstone in Brooklyn, New York, was renovated by interior designer Kiki Dennis, complete with a full restoration of the wood window framing and decorative moldings. As much of the original fabric was retained as possible.

A brownstone in Brooklyn, New York, was renovated by interior designer Kiki Dennis, complete with a full restoration of the wood window framing and decorative moldings. As much of the original fabric was retained as possible.

Pay Attention to Consistency

Be careful, however, to pay attention to the aesthetic properties of the older glass to ensure that you don't end up with a patchwork of clearly old or new individual glass panes. These can include small bubbles, slight waviness in the surface of the glass, or perhaps a greenish tint. This is where reusing or recycling old glass is a great option.

A former Amsterdam bank was transformed into a hotel, complete with a full restoration of the existing windows. Careful attention was paid to the windows and glass ceiling of the interior courtyard, so that new window panes blended in with old.

A former Amsterdam bank was transformed into a hotel, complete with a full restoration of the existing windows. Careful attention was paid to the windows and glass ceiling of the interior courtyard, so that new window panes blended in with old.

Prevention and Protection

What's the best way to make sure you keep your windows as original as possible? Regular maintenance! Regular painting of wood framing members, annual inspections of rot or termite damage, and checking for weather damage can help you make sure that your original windows stay in great condition as long as possible.

Repairs of original windows, especially stained glass, should be made using in-kind glass, meaning that the new glass matches the original in color, texture, and opacity.

Repairs of original windows, especially stained glass, should be made using in-kind glass, meaning that the new glass matches the original in color, texture, and opacity.

Kate Reggev
॰ Architect & Preservationist ॰ Lover of buildings old, new, & everything in between! Inbox me at kate.reggev@gmail.com

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