Windows and doors

Repair Vs. Replacement 

Windows are vitally important to the character of a historic property. They are a key aspect of its architectural design, yet often they are replaced in the name of efficiency. Many property owners feel this is a necessary first step and a worthwhile investment towards long-term preservation and efficiency; however, evidence from the National Trust for Historic Preservation suggests that properly done retrofits and repairs have better returns than replacement windows. This has been corroborated by a study conducted in Vermont on the energy performance of wood windows in cold climates. The study found that replacing a historic window does not necessarily result in greater savings than storm windows and other upgrades that retain the existing window sash. These partial upgrades not only retained the original window but also reduced air leakage by at least 95% and 80%, respectively, at a lower cost. 

Besides similar performance and reduced cost, historic windows Are also often made from higher-quality materials than new replacements. Windows in older homes were often built using old-growth wood, which is naturally rot-resistant and deters insects. They have been shown to last longer than their newer counterparts, and they may need to be replaced more frequently. Materials used to create old windows may also be one of a kind. This is because windows were often constructed before the early 1950s using handmade glass rather than the more uniform float glass. Lastly, changing out historic windows to entirely new ones may cause additional strain on the building itself. that is because windows and historic homes were custom-built to fit the structure and often do not match standard sizing for Windows. Therefore, The building will require custom windows or may need to be modified to match standard sizes. Because the house settles around the windows over time, removing them may also pose structural risks to the property.

Before you decide whether to replace or fully replace a widow, ask these questions: 

  • Are these windows original to the property?

  • Do they contribute to the historic/visual character of the property?

  • Can they be repaired? 

To learn more about the benefits of preserving historic windows and strategies you can view this tip sheet created by the National Trust for Historic Preservation. The Preservation Alliance of West Virginia also offers articles and informational resources on rehabilitating wooden windows. 

Types of Repairs

If windows are in good enough condition to be salvaged, several repair options may be used to improve the efficiency and comfort of your property. 

  1. Weatherstripping and caulking: Weatherstripping and caulking work by sealing the gaps between windows and doors to prevent moisture and air leakage. They have been used for over 100 years in the United States and are available in various materials for different purposes; however, the most historically accurate material for old buildings is often bronze or zinc. 

  2. Sash locks: Many people believe sash locks are primarily for home security, but they are also effective at ensuring windows are tightly closed to avoid air leakage. 

  3. Storm windows: Storm windows can be retrofitted to sit in the interior or exterior of the window sill to improve energy efficiency. These inserts can be left up year-round or removed in the warmer months. Modern storm windows do not obstruct the view or aesthetic of the original window pane and can even be made to open and close for air ventilation in summer. 

Whether you are repairing or replacing windows, it is important to follow the guidelines for preservation to remain on the National Register of Historic Places and preserve the original charm of your home. Making significant repairs or alterations to a historic property that do not meet reasonable standards set by the Secretary of the Interior may risk losing incentives and/or grant funding. 

 

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