You’d think that the architects committed to preservation and those concerned with sustainability would be the last people to disagree. You can make a good case for historic preservation as the ultimate in adaptive reuse. What do they have to fight about?
Windows, it turns out.
The National Trust is pretty clear on the value of preserving, rather than replacing, old windows. In the March/April 2009 issue of Preservation Magazine, they outline their point of view. The National Trust feels that repairing existing windows made of old-growth wood is greener than replacing them with new materials. Infiltration, which causes energy loss, can be diminished with storm windows and weatherstripping, which tighten the seal around a window. They point out that new windows will need to be replaced about every 25 years, while historic ones can last much longer than that.
Windows and doors can add up to 13 points of the 17 needed to certify a building for LEED in the energy use category, according to the most often-used LEED standard, the one for new construction. If you’re specifying a building for LEED certification, you’re looking for the most energy-efficient technologies, including those in windows.
But a few historic buildings have achieved high levels of LEED certification, and some of them have involved a compromise on windows. The University of Oregon’s Portland complex, located in three renovated historic buildings in downtown Portland, is an example of an accommodation rather than a fight. Fletcher Farr Ayotte, the architect, and Venerable Properties, the developer, recommended three buildings on the White Stag Block to the University—the Bickel Block building, dating from 1883; the Skidmore Block building, from 1889; and the White Stag building, from 1907.
In addition to the design challenges of knitting three buildings together, there was a tug between the requirements of the University, which wanted to the buildings to achieve LEED Gold certification, and the National Park Service, which maintains the buildings’ status on the National Register, a situation that Erica Ceder, FFA’s job captain for the project, called “a double threat.”
Ceder was surprised by the emotion generated by windows. “The National Register feel[s] they’re character-defining and they don’t like to see historic windows removed.” But in this case, the windows’ condition was a problem. Ceder said, “The windows were in disrepair. They had one layer of glazing and they were leaky.”
And in this case, the State Historic Preservation Office and the National Park Service, which maintains the Register, were amenable to replacement. Ceder said that an energy efficient facsimile—double-glazed and argon-filled—was an acceptable substitute for the originals. It preserved the look, and it sealed the building envelope.
Repair the windows if you can. Replace them if you must. But please, don’t fight next to the windows—they’re fragile and we want them to last.