Help for Historic Windows
January 17, 2009
One of the most wonderful aspects of our local architecture is its historic windows with their characteristic divided lite panes and historic glass. They are not only visually appealing, but their design and craftsmanship make them worthy of preservation. Unfortunately, because they are single-glazed and often in disrepair, they are also one of the largest sources of heat loss in winter and a major source of heat gain in the summer. The windows alone can be responsible for 25 to 50 percent of the energy used to heat and cool homes!
First of all, this discussion is about historic windows – unless the windows have historical significance, replace them rather than repair when they are truly worn out. New windows, with insulating and low-e glass, will make your house more comfortable and will lower your energy bills.
The repair of an historic window, with the addition of a storm window, proper sealant and weather-stripping, can result in a window with energy efficiency close to that of a new window. The repair of these windows can be labor intensive and often is not of interest to general contractors or carpenters, who are often happier replacing an old window with a new one. Companies focused on window restoration are dedicated to bringing your windows back to their original beauty and functionality. Starck House Joiners in New Hampton, New Hampshire (www.starckhousejoiners.com) and The Window Woman in Topsfield, Mass. (www.window-woman-ne.com) are two local experts in the repair and reconstruction of historic windows. The following is a description of what you should expect from a window restoration project:
Depending on the condition of your windows, their repair will fall into three categories, increasing in cost and time from 1 to 3.
1)Routine Maintenance Procedures – To upgrade a window to “like new” condition, this category generally includes the some degree of interior and exterior paint removal, the removal and repair of sash (including replacement of the glass, or reglazing, where necessary), repairs to the frame, weather-stripping and reinstallation of the sash and repainting.
2) Structural Stabilization – When the window shows some additional degree of damage or rot, additional steps required to repair the window include drying the wood and treating the decayed areas with a fungicide, filling cracks and holes with putty and painting the surface.
3) Parts Replacement – When parts of the frame or sash (the moveable part of the window) are so badly deteriorated that they cannot be repaired with by stabilizing, there are methods for replacing only damaged parts of the window with matching pieces. A skilled millwork carpenter or window restorer can duplicate window parts that can replace damaged components of the window or can even build a new window sash to match the existing damaged sash.
Once the window has been repaired, it should be made as energy efficient as possible with the use of weather-stripping to reduce air infiltration and repaired sash locks to ensure a tightly closed window.
Many styles of storm windows are available to improve the thermal performance of existing windows. The use of exterior storms is preferable because they are thermally efficient, cost-effective, reversible, and allow the retention and protection of existing windows. Storm windows frames are made of wood, vinyl or plastic, and their visual impact can be minimized by painting them in colors to match the trim color.
Although interior storm windows appear to offer an attractive option for achieving double glazing with minimal visual impact, they often cause condensation problems. The moisture which becomes trapped between the layers of glazign can condense on the colder, outer prime window, leading to its deterioration.
There is a point when the condition of the window clearly indicates that a replacement is necessary. When considering replacement windows, it is important to not only consider their energy efficiency, but also their appearance in terms of the pattern of the proportions of their frame and sash, the configuration of the window panes, muntin profiles, types of wood and characteristics of the glass. Search for a replacement that retains as much of the character of the historic window as possible.
If you have any questions, feel free to contact me or the listed companies.
Starck House Joiners www.starckhousejoiners.com
The Window Woman www.window-woman-ne.com