Mistake: 6 Leaving it leaky
Old homes leak—a lot. Depending on the region, this air leakage may be the biggest challenge to energy efficiency and the biggest opportunity for improvement.
When we remodel old homes, we regularly lower energy use by 50% to 75%, which would be really amazing if the starting point weren’t so unimpressive.
Tightening up a home built with strip sheathing and lacking insulation—an energy-inefficient tandem common in houses built before World War II—offers us a chance to leapfrog typical 20th-century insulation strategies and jump directly to 21st-century sealed assemblies. This includes a sealed crawlspace and sealed attic, which put all the mechanical systems and ductwork inside a conditioned space.
A blower-door test, which uses a large, high-powered fan to depressurize a home and reveal air infiltration, is the best way to identify leakage areas. Once those are established, I like to seal and insulate at the same time using closed-cell spray foam.
Spray-foam use has been controversial among preservationists, who are concerned about its nonreversibility (once it’s sprayed, it’s stuck to the wood). This view, however, may be changing: The National Park Service is currently revising the 1978 recommendations that discouraged spray-foam use.
Closed-cell foam works well on older homes because it reduces air infiltration, helps to keep out moisture, and unlike other insulations, does not absorb moisture that does get in. This may be less of an issue on modern high-performing homes with good water-management strategies. But these technologies did not exist in the early 20th-century homes I’ve worked on, and here in the hot, humid South, the combination of moisture and 100°F days can lead quickly to moldy walls.
Mistake 7: Installing new windows
The window repair-vs.-replace debate is an emotional one for old-home enthusiasts. Windows can be character-defining or, in the case of replacement windows, character-destroying. Increasingly, there are homebuyers who no longer consider a historic home desirable if the windows have been replaced.
Further, the energy-saving benefits of window replacement are overblown. Only 10% of a typical home’s heat loss is through its windows, according to the Department of Energy, and old windows are not as inefficient as you might think. A Lawrence Berkeley National Laboratory study found that a rehabilitated window in tandem with a storm window performs within 6% of the efficiency of the average replacement.
There’s also evidence that cheap replacement windows advertised as “maintenance free” are actually disposable, short-term fixes. FHB ran an article in 2004 that suggested 30% of the windows being replaced are less than 10 years old, which is shocking compared to windows constructed 100 years ago that continue to perform with just a little maintenance.
I do whatever I can to save old windows and make them energy efficient. This may involve new glazing, weatherstripping, carpentry work, and paint. Efficiency can be boosted with a variety of storm-window options, including fixed interior storms, custom wood exterior storms, and aluminum triple-track storms. On one project, we added an additional pane of glass to an existing single-pane sash to preserve the look, feel, and unobstructed view of the historic window. It was a lot of work, but in my view, it’s silly to replace a multicentury asset with one that may need replacing every few decades, could lower the property value, and is unlikely ever to see a return on investment.
Mistake 8: Replacing rather than reparing
Windows are not the only parts of an old home that should be restored. Custom mantels, hand-blown glass, and hand-built doors and hardware all showcase character that cannot be entirely replicated.
It’s not always architectural beauty that needs to drive improvement decisions. Old systems, such as electrical knob-and-tube wiring, can, when inspected for safety, function with perfect adequacy in certain situations. Above all, resist the temptation to replace materials because of minor imperfections. Ghost marks—for example, a hole patch marking the spot where plumbing once fed a radiator—offer tangible proof of a home’s history. Leaving these flaws in place helps to tell the home’s story.
The repair-vs.-replace debate would not be complete without addressing the ultimate replacement strategy: gut jobs. Gut jobs are wasteful and destructive, and they strip a house of character earned over many years. On a 3000-sq.-ft. Queen Anne gut job (one we were unable to avoid because of the severe state of the house relative to the improvements planned), we ended up sending 35 tons of material—half the estimated mass of the structure—to the dump.
Gutting usually involves removing plaster, which is considered superior to drywall for sound, look, and feel. Installing drywall in its place presents a number of challenges due to the varying depths of many old balloon-framed studs as well as the difference in thickness between plaster and lath (1 in. or more) and maximum 3⁄4-in. drywall.
If authentic materials must be removed or replaced, this should be done deliberately, with the intent to reuse. Anything less is just wasteful.