As schools and universities look to preserve and renovate their older facilities, administrators face the challenge of repairing or replacing windows while trying to maintain the architectural character of the original design.
“If the windows are important in establishing the historic character of the building, insensitively designed replacement windows may diminish — or destroy — the building's historic character,” according to the Heritage Preservation Services (HPS) division of the National Park Service.
The HPS has published preservation briefs that offer guidance for repairing and replacing windows while preserving their historical significance.
To preserve architectural significance, rehabilitation and repair are preferred, but not always feasible.
“If it is shown that repair cannot be accomplished due to extensive deterioration… any replacement window needs to match the historic sash, the pane size and configuration, the glazing, the muntin detail and profile, and the historic color and trim,” says the HPS. “Using the same type of material is always the preferred recommendation. If repair is not feasible, then a compatible substitute material can be considered.”
Manufacturers often can customize products to meet unique needs.
“While stock modern window designs do not share the multi-pane configuration of historic windows, most of these manufacturers can reproduce the historic configuration if requested, and the cost is not excessive for large orders,” according to the HPS recommendation for steel windows.
For wooden windows, the HPS recommends consulting with local historical associations and state historic preservation offices, checking building supply firms, local woodworking mills, carpenters, preservation-oriented magazines, or catalogs or suppliers of old building materials for product information.
Schools should take improved energy efficiency into account when choosing replacement windows, but should not let that issue override other considerations.
“Energy conservation is no excuse for the wholesale destruction of historic windows that can be made thermally efficient by historically and aesthetically acceptable means,” says the HPS brief on historic wooden windows.
Percentage of public schools that rate the condition of their walls, finishes, windows and doors as less than adequate.18
Percentage of public schools with less than adequate walls, finishes, windows and doors that are planning to replace them.29
Percentage of public schools with less than adequate walls, finishes, windows and doors that are planning major repairs or renovation.53
Percentage of public schools with less than adequate walls, finishes, windows and doors that have no plans for repair, renovation or replacement.
Source: Survey on the Condition of Public School Facilities, 1999