How to Save Historic Windows on an Existing Property
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.