Preservation and sustainability
. What does one have to do with the other? If we examine these terms more closely, we can see that older buildings are inherently “green
” or sustainable because of “embodied energy” (all of the energy used to build the building that would need to be expended to build something else). In fact, the report
from the National Trust for Historic Preservation “The greenest building” states:
“This study finds that it takes 10 to 80 years for a new building that is 30 percent more efficient than an average-performing existing building to overcome, through efficient operations, the negative climate change impacts related to the construction process.”
This statement about life cycle analysis indicates that the construction process is resource intensive (both in production and transportation of new materials and landfill debris – about 20%-25% of landfill waste is construction-related). Reusing an existing building is the ultimate recycling, so preservation and sustainability are often inextricably linked, and this link highlights the importance and value for sustainability inherent in preservation.
Photo by Random Institute on Unsplash
PRESERVATION’S LINK TO SUSTAINABILITY
Not surprisingly, both the preservation and the “green”/sustainable initiatives have significant common ground and can work in concert with one another. This is particularly relevant in light of concerns regarding climate change and major environmental concerns. The National Trust for Historic Preservation formed the Preservation Green Lab in 2009 to strengthen the connection between preservation and sustainability, and updated the name to The Research and Policy Lab in recognition of expanded needs. The National Trust for Historic Preservation has increased focus on climate change impacts on our heritage. There is also an International Climate Heritage Network to address the intersection of climate change and other environmental disasters on arts, culture, and heritage.
However, at times in the recent past, green and preservation agendas have been at odds and there has been a bias in the sustainable building field to start over with new buildings and materials, as pointed out by Tristan Roberts, and The Washington State Department of Archaeology and Historical Preservation’s (DAHP) Sustainability and Historic Preservation Executive Summary from 2011. The Whole Building Design Guide’s Historic Preservation Subcommittee (WBDG) notes that there has also been a stigma attached to preservation and it has been (often inaccurately) labeled as inefficient and requiring overwhelming or costly procedures to retrofit energy efficient systems into old systems. Additionally, Roberts reports that certain sustainable products that are made of recycled content or other sustainable materials may not be approved by the National Park Service’s Secretary of Interior’s Standards for Rehabilitation simply because they disrupt a building’s character-defining appearance. However, preservation and sustainability are far from being mutually exclusive. As Roberts reports:
“Both the environment and cultural heritage suffer when buildings are treated as disposable.”
Below, we outline characteristics of preservation that lend themselves to sustainability:
- Energy Efficiency. As noted earlier, it also takes less energy to maintain or rehabilitate an existing building than to demolish an existing building to construct a new building, even if that new building is “green.” Restoration involves less carbon emissions than new construction. Comparatively, DAHP noted in 2011 that new buildings accounted for 40% of all extracted energy sources and 68% of all consumed energy per year. DAHP also cited the U.S. Department of Energy (DOE) who shared data indicating that “commercial buildings constructed before 1920 actually use less energy per square foot than buildings from any other decade up until 2000.” New buildings made of new materials means one must consume energy to both create and ship those materials, and this also contributes to carbon emissions. DAHP adds that many historical buildings were designed with “passive systems,” or systems that took advantage of things like natural light, ventilation, and solar orientation when electrically-powered options did not exist. These passive system characteristics are all inherently sustainable and meet the same “green” goals of the sustainability camp. You can read more of our articles on energy efficiency in our archives here.
- Durability and Waste. Preserving a historical building reduces consumption of materials, and retaining old material creates less construction landfill waste. Green buildings should have materials that are both durable and repairable, whether that green building is new or old. Many new green building products are durable, but not necessarily repairable (read our repair archives here). Additionally, to build a new building with new materials, you have to create and ship the resources (both of which take energy), and often they are placed on newly cleared land which takes energy but also may be removing resources such as forest or farmland. Rehabilitating an existing or historical building eliminates a lot of these issues. Even reusing durable, salvaged materials from buildings that are torn down keeps those materials out of landfills and provides green materials for another building. However, more wasteful decisions are perpetuated, as Roberts points out that the construction industry often falls prey to “short-term thinking,” focusing on what works in-the-moment and disregarding long-term outcomes. Despite these benefits of preserving or rehabilitating older buildings, there can be challenges related to durability and waste in older buildings. Roberts notes that not all older buildings were well-built with durable material or construction, so in some cases, building damage is not due to neglect or abuse, but the way the building was constructed (e.g., some buildings with structural steel that is corroded cost a lot to repair). Further, as more modern buildings age and qualify as “historic” each year, these sometimes less durably-built structures pose new challenges for both the preservation and sustainability movements.
“GREENING” YOUR HISTORICAL COMMUNITY, BUILDING, OR HOME
Several efforts at the international and national level have been highlighted here for increasing connections between preservation and sustainability. WBDG’s Historic Preservation Subcommittee adds several guidelines that marry LEED guidelines for “greening” existing buildings with processes that incorporate specialization for historical buildings (here). However, there are several things individuals in and building and homeowners can do as well. On a community scale, The National Trust for Historic Preservation includes information on helping preserve your community and designating a historic place. Below are tips for owners of older buildings and homes. These are based primarily on the framework provided by the National Trust for Historic Preservation’s Meghan White in “8 Ways to Green Your Historic House“, listed below, as well as information from other articles and our own expertise:
- Conduct an energy audit. Know where energy may be leaking. White states “A popular example is the blower door test. This test involves using a high-powered fan to take the air out of the building, which depressurizes the interior. The difference in air pressure is then measured with an air pressure gauge.” The pressure difference allows outside air to come into the building via openings, which reveals areas you’ll need to seal.
- Don’t replace windows (or doors, or siding, etc.). As we’ve noted several times, a big misconception is that historical windows are to blame for the drafts in homes. White reports “As the National Trust’s Research & Policy Lab (formerly known as the Preservation Green Lab) notes in their study Saving Windows, Saving Money, historic windows rarely deserve to be completely replaced. Instead, weatherstrip them or install minimally invasive storm windows so that they keep the drafts out and lower your energy bills. The study found that retrofitting windows are the most cost-efficient way to decrease a historic house’s carbon footprint. As a bonus, old growth wood found in historic windows lasts longer than modern day wood, so preserving your historic windows will keep you from having to replace them more often.” Similar points can be made for doors, siding, and many exterior home parts that separate the outside from the inside. DAHP adds that more energy is lost from plumbing openings and uninsulated ducts than windows. The key is to repair, restore, and maintain these protections from the outside elements.
- Insulate the attic and basement. White notes that energy escapes through uninsulated spots such as basements, crawl spaces, and attics. Insulating them can help to prevent air from escaping. They say “Cellulose is a great option because, unlike spray foam, it’s reversible.” They also caution “You should refrain from insulating walls because you’re removing the permeable vapor barrier inherent in historic structures. The walls of historic houses are made to breathe, but inhibiting movement of air and heat through and around the wall can lead to issues like trapped moisture.” This issue is closely related to our points about differences in modern mortar and historical mortar, and the inherent breathability of old wall materials.
- Take advantage of your house’s natural passive heating and cooling. White says “Artificial cooling and heating methods can be some of the highest energy consumers in a historic house.” They suggest using your historical home’s shutters to cool your house naturally: open your windows and latch the shutters to allow natural air flow. The added bonus is it will shade your interior from the sun. Window awnings that are historically appropriate can also provide similar benefits. In cases where you want or need additional electric components, consider finding a preservation and sustainability-minded HVAC professional who can retrofit systems with little disturbance to your home’s historic fabric, as we discussed here.
- Consider installing renewable energy sources. Installing solar, wind, or geothermal renewable energy sources on your historic property are also options to consider. White says “Solar panels produce electricity naturally and will help lower your bills. When connected to a utility power grid, modern wind turbines can also help create electricity using renewable resources and in a more cost-efficient manner. Read more about installing solar panels on historic properties here.” Tesla has also developed solar panels that are extremely sympathetic to the historical aesthetics of an older home, though it may be cost-prohibitive for many.
- Pay attention to your landscaping. Trees may help to conserve energy in your house,with deciduous trees providing shade in the summer and fallen leaves allowing sunlight to warm your house in late fall and winter. Another issue we acknowledge is environmental damage due to combined sewer systems in many cities. When it rains too much the system becomes overwhelmed and this causes untreated sewage to be dumped into streams and rivers and contaminates waterways. The EPA fines communities every time this happens. As an individual homeowner, you can prevent some of your own contribution to this problem by: creating a rain garden to divert the water away from the storm drain and also away from the foundation; installing permeable pavers laid in the traditional manner (with sand underneath instead of mortar); and you can build a drywell. Check with your local municipality to see if they have a grant to help defray the costs of to property owners who make these changes.
- Change your Lightbulbs. White points out “According to the General Services Administration, High Efficiency Incandescent (HEI) lamps reduce energy by 50 to 75% and use only 25% of the energy that regular incandescent bulbs use. They also don’t alter the appearance of historic light fixtures where the bulbs are visible, like LEDs do. Otherwise, LEDs are a good option when the bulb is obscured by opaque shades or lenses.”
- Reuse old materials or salvage. White encourages readers renovating historical buildings to replace missing pieces with materials from salvage companies before resorting to all-new material. This helps preserve historical pieces and prevents some landfill waste.
Preservation and sustainability have much in common, and destroying or demolishing old buildings is more wasteful than helpful, even when replacing it with a new “green building.” It is best to preserve what we do have, by repairing, restoring, and maintaining these buildings.