Is renovation the key to sustainability of our cities?

Is it economically and environmentally more viable to extend the life of an existing building through renovation – or to demolish it, dispose of it, and rebuild?

Researcher Peter A. Bullen of the Curtin University of Technology in Perth, Australia, asked building owners that question and found 83% of respondents felt it was preferable to adapt rather than demolish.[i] His research found a growing perception that it is better to convert old buildings into new uses, than to tear down the past, transport the rubble to a landfill, and rebuild.

“Reusing the existing building stock, particularly as a result of performance upgrading, has been identified as having an important impact on sustainability of the built environment,” he says.[ii]

The commercial real estate magazine Globe St. agreed, noting a growing trend in the practice – particularly when it comes to converting office buildings to multi-family residential. “In general, adaptive reuse for commercial buildings is gaining favor due to its potential for higher returns, cheaper material costs and being more economical compared to demolitions and having a reduced environmental impact on the area by much less hauling to landfills,” the magazine reported.[iii]

And while our consumer-based society is driven by the assumption that socio-economic growth drives a demand for new buildings, the number of buildings actually constructed in developed countries each year only corresponds to 1.5% to 2% of a community’s existing building stock. At that rate of construction output, Bullen found, it would take anywhere from 50 to 100 years to replace the current stock.[iv]

That means our buildings are here to stay – frequently for much longer than they were designed to.

The average lifespan of a commercial buildings today is about 50 years, according to SMR Research Corporation, which conducted an extensive analysis of commercial buildings by type and use.[v]

A typical “big box” store today may be designed to last for just eight years, according to a study by the University of Texas – which attributed this “throw away” mentality to economic pressures and the need for business to adapt to changes in the marketplace.[vi]

In the past, building designers had to account for nature: thick-walled structures helped regulate temperatures indoors to fight off blazing heat or biting cold. Windows were strategically placed to make the most of light and ventilation. But those long-held strategies became irrelevant with cheap artificial lighting and HVAC systems. The focus in homebuilding became not so much to create a structure that would last, but to erect a dwelling that would serve the needs of the buyer and encourage a quick and easy sale, according to research by the University of Texas.[vii]

And because life didn’t change much in those early days, the usefulness of those buildings endured for centuries. That started to change in the 20th century, when plumbing, electricity and transportation came into vogue and industrialization sparked economic prosperity that fueled an ever-changing landscape for both residential and commercial buildings.

Just think about the now-obscure elements in a building that were once considered cutting-edge: the milk chutes for delivery to homes; dumbwaiters; telephone niches in hallways and phone booths in lobbies.

Pressure to adapt

Rapid technological and social advances can quickly render a building’s design obsolete. This has created a booming industry in redesigning interior spaces to better serve the needs of communities today. It may involve the conversion of a warehouse into a shopping mall, a factory into live/work lofts, an old church into a restaurant, or stately courthouses into museums. An old hotel might be converted to mixed-use development with more spacious units on the upper floors. This process of reinvention brings an important use to meet the needs of a new community and preserves a piece of history that would otherwise be lost forever.

It’s happening all over the world, but some recent examples cited by the California Department of Parks Office of Historic Preservation include:

The Maydestone building in downtown Sacramento. Originally built in 1912, this Mission Revival style hotel deteriorated and a fire in 2003 left it derelict for many years until it was redeveloped in 2012 into apartments, preserving most of the historic features intact.
The Presidio Hospital in San Francisco. Originally built in 1895, the adaptive reuse of this building called for the removal of 1950s-era wings and the conversion of the facility into 154 luxury apartments.
The Pier 15 conversion in San Francisco involved the reuse of an industrial pier built in 1931 to house the Exploratorium, now one of the city’s most popular tourist destinations.

The team at Optimum Seismic has performed many adaptive reuse projects over the years, including the conversion of a historic hotel in downtown San Luis Obispo into a mixed-use project of 48 apartments and retail; a similar conversion at the Mayfair Hotel in downtown Pomona; and the conversion of Victorian homes into student housing for the University of Southern California.

In the vast majority of these and other adaptive reuse projects, it’s not simply about reusing the space inside the building shell, it involves other upgrades as well: such as seismic retrofits, electrical rewiring, plumbing replacement and other improvements that add significant value to the building.

Lifecycle assessment and sustainability

Today, with heightened interest in sustainable construction, building practitioners are evaluating environmental impacts of design decisions over the full lifecycle of a building. This process, known as lifecycle assessment, or LCA, requires an estimate of a building’s useful life span. More statistical data on actual service lives will assist in keeping LCA results meaningful.[viii]

Resilience goes hand in hand with sustainability. What could be better for the earth than to conserve and continue using what is already in place? To do so avoids the negative impacts of demolition and disposal, consumption of natural resources for production of new materials and the need to transport everything to and from the site.

Resilience also requires constructing a building that can be adapted to multiple uses in the future. This is as much a sociological exercise as a brick-and-mortar solution. Communities and their needs change with advances in technology, population shifts and new modes of transportation.

Bullen, in his research, found several qualifying factors that made adaptive reuse a positive strategy[ix]:

It reduces resource consumption, energy use and emissions
It extends the useful life of buildings
It is more cost-effective than demolition and rebuilding
It creates valuable community resources from unproductive property
It revitalizes existing neighborhoods
It reduces land consumption and urban sprawl
It retains streetscapes that maintain a sense of place
It preserves visual cultural heritage

Architect Carl Elefante once said, “The greenest building is the one that’s already built.” A new building may be “green” in every sense of the word, but if the new building replaced a demolished one, all the embodied energy is lost and it could take anywhere between 10 and 80 years for the new building to overcome the loss of the embodied energy in the demolished building.[x]

Important elements to a building’s innate longevity include its ability to remain a viable place to live or do business. This frequently hangs on the limited relevance of these building components:[xi]

Style: Kitchens, bathroom appliances, paint and floor coverings. These normally adhere to style for 10 to 15 years before they become outdated.
Function: Windows and flat roofs last about 30 years.
Longevity: The actual building shell lasts between 70 and 100 years.

Recognizing this, Renato Piffaretti of Swiss Life recommends that building owners put aside 1 percent of a building’s value every year to ensure it can be renovated every 30 years. “An important component of longevity is a building’s adaptability”, he says, “it should be easy to change the room layout. For example, preferences regarding kitchens and bathrooms have changed a lot over the past 30 years. However, it is difficult to make the required changes to 30-year-old buildings so they often have to be knocked down.”

Yale-educated architect Dave Sellers, credited with helping launch the design/build movement 50 years ago, recently built a home in Vermont designed to last for 500 years. The home has a mostly concrete exterior, with a flexible interior floor plan that can adapt to changing needs easily.[xii]

“This house is designed to handle a single family, or two families, or three families,” he told Green Building Advisor. “Or it could be designed to handle 50 people. There are no interior walls. It’s like a big barn. You sort of fill in. We basically built post and beam out of concrete, and you can build whatever you want in it. It can change over time without wrecking the house.”

Interior space

The space inside a building should adapt to new needs as dictated by our lifestyle. Builder and Developer magazine recently underscored the following changes for 2020 home design:[xiii]

Prep pantries, which allow for much of the work involved in entertaining to take place behind doors, so the kitchen can continue to serve as an attractive hub for entertaining.
With large computers a thing of the past, the computer center or kitchen desk will become a thing of the past. Instead, a command center will take its place: including room for charging stations, package deliveries and tablets.

Other trends will include:

Environmentally conscious designs with lower energy needs and reduced carbon footprint.
Window-to-wall ratios of less than 30%
Maximum wall, roof and foundation insulation
Tight building envelopes so all openings are sealed.
Energy-efficient HVAC systems
Water efficient fixtures
High ceilings to deliver openness and freedom throughout the home
Open floor plans to enforce togetherness and create more free space

Building safety upgrades

California’s Northridge Earthquake of 1994 exposed the vulnerability of several of our popular building types – including older wood-framed, soft-story structures, which collapse under significant seismic shaking. The quake also underscored the interdependency of our built environment.

“Communities are complex, interconnected systems… (that) are rarely, if ever, isolated from one another. When adverse events occur, all components in the local system must continue to function,” the International Code Council stated. “An office building with functioning electricity cannot effectively operate if employees are unable to commute because public transit is shutdown. A structure built to code that stands tall in a disaster must be reachable by roads and sidewalks during and after that disaster to be occupied. Employees can’t effectively function if grocery store shelves are bare, etc. For a community to be resilient, it must understand the resilience of each community function and how well each can respond to adverse events. That means having a community plan to get critical systems operating again. Resilience in the built environment begins with strong, regularly adopted and properly administered building codes, but communities must look across all of its interconnected functions to truly be a resilient community.”[xiv]

Today, there are several new materials being adopted to enhance the lifespan of our built environment. These include:

Self-healing concrete: will biologically produce limestone to fill in cracks that appear on the surface of concrete structures
3D graphene: a three-dimensional version developed by MIT that has only 5% of the density of steel, yet is ten times stronger
Laminated timber: mass-produced prefabricated solid engineered wood panels that are lightweight, strong, with superior acoustic, fire and seismic performance
Modular bamboo: Stronger than wood and better for the environment
Wool brick: stronger and more environmentally friendly than conventional brick
Hydroceramics: a composite material that can lower temperatures indoors by 5 degrees Celsius
Bioreactors: to generate green energy
Invisible solar cells: to generate electricity without a high-profile solar array

In tandem with these new materials, recent improvements in building codes and applications mean today’s structures will likely outlast those constructed 50 or 60 years ago.

Perhaps the American Institute of Architects said it best: “Adaptive reuse breathes new life into old bones. It is a method of protecting historically significant buildings from demolition. It promotes sustainability and counteracts urban sprawl. Best of all, it challenges us to find value in the past and make it not just new again, but different and better.”

[i] Peter A. Bullen, Curtin University of Technology, Perth, Australia. “Adaptive Reuse and Sustainability of Commercial Buildings,” https://www.researchgate.net/profile/Peter-Bullen-4/publication/235264539_Adaptive_reuse_and_sustainability_of_commercial_buildings/links/56b54e8a08aebbde1a77c5cc/Adaptive-reuse-and-sustainability-of-commercial-buildings.pdf

[ii] Ibid.

[iii] Globe St., “The case for office-to-multifamily adaptive reuse,” https://www.globest.com/2022/03/14/the-case-for-office-to-multifamily-adaptive-reuse/?slreturn=20220304005510

[iv] Peter A. Bullen, Curtin University of Technology, Perth, Australia. “Adaptive Reuse and Sustainability of Commercial Buildings,” https://www.researchgate.net/profile/Peter-Bullen-4/publication/235264539_Adaptive_reuse_and_sustainability_of_commercial_buildings/links/56b54e8a08aebbde1a77c5cc/Adaptive-reuse-and-sustainability-of-commercial-buildings.pdf

[v] Stuart Feldstein, SMR Research Corporation, https://www.commbuildings.com/ResearchComm.html

[vi]https://soa.utexas.edu/sites/default/disk/munich_papers/munich_papers/10_02_su_maddox_randall.pdf

[vii]https://soa.utexas.edu/sites/default/disk/munich_papers/munich_papers/10_02_su_maddox_randall.pdf

[viii] https://cwc.ca/wp-content/uploads/2013/12/DurabilityService_Life_E.pdf

[ix] Peter A. Bullen, Curtin University of Technology, Perth, Australia. “Adaptive Reuse and Sustainability of Commercial Buildings,” https://www.researchgate.net/profile/Peter-Bullen-4/publication/235264539_Adaptive_reuse_and_sustainability_of_commercial_buildings/links/56b54e8a08aebbde1a77c5cc/Adaptive-reuse-and-sustainability-of-commercial-buildings.pdf

[x] Claremont Courier, “Adaptive Reuse Revisited,“ March 31, 2022. https://claremont-courier.com/latest-news/adaptive-reuse-revisited-64740/

[xi] https://www.swisslife.com/en/home/hub/what-is-the-lifespan-of-a-house.html

[xii] https://www.greenbuildingadvisor.com/article/a-house-to-last-for-500-years