Today’s HVAC and building-envelope technologies further enhance the inherent sustainable advantages of renovating historical structures.
By John D. Lesak, AIA, LEED AP, FAPT, Principal, Page & Turnbull
Building construction and operation are major contributors to global warming. A 2016 report from the EPA shows that commercial and residential building operations account for 11% of all greenhouse-gas emissions in the U.S. Good design is green design, and architects have a responsibility to share best practices, including repurposing and upgrading existing buildings. There is almost unlimited potential in adaptive reuse and redevelopment, and rehabilitating historical buildings represents one of the most sustainable approaches to the design and construction of built space available to us, for several reasons.
For one, the carbon footprint associated with construction of even the most sustainably designed new building is considerable. Life-cycle analyses and other calculations of embodied energy often reveal a lengthy payback period, in terms of carbon output. A new energy-efficient home, for example, may take between 35 and 50 years before its efficient operations offset the carbon dioxide expended during construction, according to the National Trust for Historic Preservation, Washington (savingplaces.org). Leveraging the original energy investment represented by saving tons of stone, steel, wood, and concrete, with a deep energy retrofit, drastically reduces the payback period. There are even multiple examples of historical buildings operating with net-zero-carbon emissions.
Learn more about restoring historical structures in our interview with John Lesak.
Another reason is that existing building demolition and new construction are responsible for thousands of tons of building-material waste going into landfill, which is decidedly unsustainable. Additionally, the legacy architectural norms underpinning older buildings are often intrinsically sustainable because they were built before reliance on building systems. For example, typical mid-20th-century high-rise office buildings often featured large rectilinear floor plates, which were considered economically efficient. Electrical and mechanical systems provided light and air to the interior areas, increasing the rentable square footage per floor.
Pre-Depression-era buildings, in comparison, characteristically used smaller floor plates containing light courts that permitted daylight and fresh air to penetrate the inner spaces. Their architects considered site placement and fenestration to optimize occupant comfort and provide daylight.
Unfortunately, many older buildings were modified considerably over the years to accommodate the latest building technologies, such as fluorescent lighting and air conditioning, often to the detriment of their aesthetic qualities. It’s important to recognize that these inherently sustainable building features can be restored, often with more efficient performance.
A common-sense three-step approach to improving building performance involves:
1. reducing demand
2. using efficient technology
3. providing controllability.
For historical structures, this approach must be balanced against preserving or restoring character-defining features.
The first step, reducing demand, involves using passive measures to reduce the need for mechanical systems. These include adding insulation, improving windows, and maximizing daylight and views. Serving as architect and preservation architect, Page & Turnbull designed five different insulation systems for the Antelope Valley Indian Museum in Lancaster, CA, to provide a museum-quality environment within an eclectic vernacular building in the high desert.
Most critical was the roof. Adding tapered insulation to the topside introduced an air barrier and improved seismic resistance while preserving a highly decorative ceiling.
Likewise, the design team reduced energy demand for the mixed-use Carson Block Building in Eureka, CA, by restoring the elegant façade and removing bad modifications made over the years. Reconstructed storefronts, combined with skylights over open stairwells, flood the interior with welcome natural daylight, resulting in reduced consumption of electric lighting.
The second step requires upgrading existing systems or inserting high-efficiency equipment. For Antelope Valley Museum, the team replaced an old swamp cooler and window units with a heat-pump system connected to geothermal wells. For the Carson Block Building radiant steam heating system, the radiators were retrofitted from steam to hot water and the 80-year old boiler replaced with modern, efficient water heaters.
The third step, controllability, combines two critical concepts: using energy only in populated spaces and giving individuals the ability to self-adjust illumination and climate to make themselves comfortable and, therefore, more productive. Fortunately for historical buildings, state-of-the-art systems have smaller, slimmer profiles, requiring less intervention to install than those produced as recently as five years ago.
Sometimes change is necessary to improve the use of a historic building. Converting the former Masonic temple in Glendale, CA, into regional headquarters for CBRE provides a good example. Working with Gensler, Page & Turnbull introduced a sustainable intervention rather than a strict preservation approach, breathing new life into an Art Deco treasure that had been unused for three decades. The project team introduced penetrations into the side and rear concrete walls for new windows, improving circulation and adding light to activate the interior. Combining rehabilitation of original detailing, including original wooden trusses from the 1920s, the result is a unique blend of architectural history and contemporary commercial workplace application.
John D. Lesak, AIA, LEED AP, FAPT, is a principal with the award-winning innovative design, architecture, and historic preservation firm Page & Turnbull (page-turnbull.com), and manager of their Los Angeles office. Lesak specializes in the preservation, rehabilitation, repair, reuse, and maintenance of historic structures.