New Life for Old Double-Hung Windows
With new weatherstripping, weights, pulleys, and ropes, you can improve performance without compromising historical authenticity.
Synopsis: There’s a good reason why traditional double-hung windows have long lives: They use a simple layout and have basic operation. Even the best old windows can use a little help, though. New Orleans restoration carpenter John Michael Davis describes his methods for upgrading traditional double-hung windows to make them energy-efficient and smooth while also keeping them historically authentic. Davis begins by disassembling the windows; repairing and/or upgrading parts; sealing gaps to halt air leaks; then tuning up the channels, weights, ropes, and pulleys.
Magazine extra: View a photo essay where Davis shows you how to fit new sashes into old jambs.
A client recently complained to me about how badly the old windows rattled in his historic home. He wanted to stop the noise as well as the air infiltration, but he didn’t want me to replace the windows. Like me, my client understands the important role that original windows play in preserving an older home’s historical integrity.
As a carpenter who specializes in restoration projects in New Orleans, I’ve come to appreciate not just the beauty of old windows but also their solid construction. All the sashes I see are made from locally milled cypress, a wood that has long been prized for its strength, its workability, and its rot-resistant qualities: ideal characteristics in this hot, wet climate. With the resources available today, boosting the efficiency of old sashes doesn’t mean tearing them out or painting them shut. You can have smooth-working windows original to the house that don’t rattle in the wind or make you dread next month’s energy bill.
Old sashes work better
Most people who want to address the issue of leaky windows tend to have a knee-jerk reaction: Either install storm units over the existing window opening, or remove the old sashes in favor of replacement windows (new units that insert in the old jambs). While storm windows can be installed to look unobtrusive, they are a pain to operate. To me, the much-more-expensive method of installing replacement-window units also has disadvantages. For starters, many of them don’t come close to operating as effortlessly as old sashes hung with counterbalanced weights. Unlike the pulley-and-counterweight system, which has few working parts, replacement windows contain many pieces that can break down over time, resulting in operation that deteriorates with age.
As an alternative course, I prefer to keep as many of the existing elements that make old houses unique and historical as possible, including the windows. Because windows have such a large impact on a house’s appearance, updating them with new technology that doesn’t detract from historical aesthetics is a far better (and more environmentally responsible) option.
My process involves removing the sashes from the opening, but it is far cheaper in the long run than the aforementioned alternatives. When upgrading windows, I usually repair damage to sashes, casings, jambs, and sills rather than replace them. Even highly durable cypress can fail in spots, rather than wholesale like lesser woods; repaired cypress will still be better than most any new wood everywhere else. I use two-part epoxy putties, adhesives, and special coatings to repair and protect these pieces.
The channel that the sashes move in should be tough but slippery. I coat the channel with DuPont Imron (www.dupont.com) two-part polyurethane over DuPont’s Corlar epoxy enamel. These products are available only through industrial suppliers.
For more photos, drawings, and details, click the View PDF button below: