New Construction? Name Your Poison. But Greenest is not Always Easiest

More than ever, the historic preservation movement is aligned with the sustainability movement in seeking to use what we have wisely in order to create healthier, more livable communities. As the new mantra goes: the greenest building is one that is already standing. Translated: Reuse an existing structure is environmentally preferable to new construction. The savings involve not just the materials themselves, but the energy and related costs: sequestered carbon that went into the original construction, demolition waste and its disposal, and so forth.

Marlboro Lights vs. Reds? We're still smoking

A recent much-discussed study by the National Trust for Historic Preservation provided empirical proof for this belief. That was the lead-in of an article in the Oregon Daily Journal of Commerce, which also gave me a nice pull quote illustrating the point:

When we say something is green and it gets some sort of accolade or LEED certification, in my opinion, what we’re really doing is simply smoking Marlboro Lights as opposed to Marlboro reds,” said Jeff Myhre of Myhre Group Architects. “We’re still smoking. We’re still paving. We’re still polluting. We’re still having an environmental impact on the planet, and that’s for any new building, period.

The principle is sound, and the quote serves as a great cautionary reminder. However, other cautions are also in order. There are times when new construction is simply necessary, or at the least, on balance the most practical choice. The new integrated science center at Amherst College (about which more in the future) is one such example. The green reuse principle could moreover be prefaced with the phrase, "all things being equal." Of course, things are not always equal. As the article points out, even assuming a structure is suitable for the intended purpose, adaptive reuse poses many practical challenges.

Portland, Oregon, the article explains, is a particularly instructive case because various factors complicate the equation of reuse with best practices. On the earthquake-prone west coast, for example, required code upgrades for seismic protection can be very costly, to the point that reuse is not economically viable or at least not attractive enough to owners or investors. In addition, one needs to take into account the nature of the specific structure, meaning both the type of building and the time required to recoup the energy savings of new, efficient construction. (Preservationists are well familiar with the latter issue from their attempts to caution property-owners regarding the exaggerated claims by manufacturers of replacement windows—which reminds me that I need to do a post on that one of these days.)

Do the homework, do the math

The general preference for reuse as a green policy must therefore be differentiated:

But environmental benefits of such projects can also be significant.

The “Greenest Building” study concluded that if Portland were to retrofit and reuse the single-family homes and office buildings likely to be demolished over the next 10 years, it could reduce carbon emissions by approximately 231,000 metric tons – 15 percent of Multnomah County’s total reduction target for the next decade.

The report compared environmental impacts of seven types of renovations – such as commercial to office, warehouse to office and warehouse to multifamily – in four cities: Chicago, Atlanta, Phoenix and Portland. It found that 10 to 80 years are needed for a new building 30 percent more efficient than an average-performing existing one to overcome the negative climate change impacts related to construction.

The article goes on to consider further details, including policy "carrots" that can make reuse more affordable and attractive. It also notes that the Historic Preservation League of Oregon will come out with a report on this issue in October.

So, no easy and automatic, one-size-fits-all answers, but a sound principle that should be remembered and applied first. As always, one has to do one's homework—and the math.



Reference: Lee Fehrenbacher, "The high cost of adaptive reuse in Portland," Oregon Daily Journal of Commerce, 21 August 2012.