Don’t throw the past away
You might need it some rainy day
Dreams can come true again
When everything old is new again

These popular lyrics, from the 1974 movie “All That Jazz,” reflect the continual push by society to tap into something unique, even when it seems that everything has been done before.”

It’s somewhat tongue-in-cheek, but the song points to our nature to grasp fleetingly at the temporary —always believing that something newer and better will come around soon.

This is not the attitude to take when designing our built environment. Structures should be planned and constructed to last and to adapt to changing needs over time.

Mankind has been capable of building structures that last for millennia. The great pyramids (2,600-2,500 BC), the Parthenon (432 BC), ancient temples of Asia, European castles and row houses date back hundreds if not thousands of years.

What is the average lifespan of a structure built today?

In most instances, it’s about 50 years.

Buildings of the past were designed to last, and because of a general stagnation in how people used their built environments, their usefulness 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.

Pressure to adapt

A study by the University of Texas attributes this to economic pressures and the need for business to adapt to changes in the marketplace, noting that a typical Wal-Mart store today is intentionally designed to last no more than eight years.[i]

Technological advances and heightened requirements for human comfort, convenience and style now require continual upgrades to maintain a structure’s relevancy in society. Forced ventilation HVAC systems, plumbing, electricity and other “modern” conveniences are frequently visible in older structures that have been renovated for relevancy today, particularly in older masonry buildings.

But the shell of these structures was constructed to last.

In 1945, a B-25 bomber crashed into the Empire State Building. It happened on a Saturday, when an Army pilot on a routine transport mission made a bad turn in heavy fog. Fourteen people were killed, and the building suffered $1 million in damage, but was open for business that following Monday.[ii]

“Back in the early 20th Century they were still calculating everything by hand, so they always added extra steel just in case,” structural engineer Roma Agrawal told the BBC. “Even though the Empire State Building is less than half the height of the Burj (Khalifa) in Dubai, it weighs two-thirds as much.[iii]

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.[iv]

Today, with heightened interest in sustainable construction, building practitioners are beginning to evaluate environmental impacts of design decisions over the full life cycle of a building. This process, known as life cycle 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.[v]

If the average building in the U.S. is 50 years old, just how old is the average home in America?

The U.S. Census determined that in 2001 the United States had 119,117,000 residential buildings, with an average age of 32 years. Statistics Canada reports that the average age of all non-residential buildings in Canada in 2003 was 17.9 years.[vi]

Surprisingly wood buildings in this study had the longest life spans.

Believed to be short-lived due to risk of fire or biodegradation, a review of demolished wood buildings showed that most were older than 75 years, while over half of all demolished concrete buildings fell in the 26- to 50-year category. This shows that wood can be used to meet longevity expectations, and it may be a preferred material in cases where an owner may want the option of modifying the layout or uses later on.[vii]

Life stages of buildings

Buildings have their own lifespan, just like us, and each phase reflects conditions unique to their age.

The American Institute of Architects defines these phases as: materials manufacturing, construction, use and maintenance, and end of life.

But for the purposes of this article, we will look solely at the use and maintenance phase of a structure’s lifespan: How it functions and serves its owners needs over time.

Phase 1: (1 to 5 years.) In the first years of a building’s completion, the structure is being handed over from the developer to the first owners. All assets are new and covered under warranty, and maintenance is limited to mostly cleaning activities.

Phase 2: (5-15 years.) It is during this period when owners begin having to make repairs. Signs of long-term replacement needs, such as a roof that is beginning to wear, or fissure cracks in walls and pavement, hint at larger repairs that may be needed down the road.

Phase 3: (15-50 years.) This period, while broad in time, reflects the point at which a building may need reconstruction and/or remodeling to address structural deficits and/or repurpose the layout to better suit the needs of the owner.

Phase 4: (50+ years.) At this point, most major assets have been through at least one renewal cycle, and if so, the structure returns to the Phase 2 stage, only to repeat the cycle.

This process of renewal can continue for as long as the structure presents a viable investment to the owner.

Recognizing this, building designers and architects are beginning to shift their focus on more sustainable designs that are disaster resilient and will stretch the value of a building long into the future.

Designed to last

Architects are taking disaster resilience seriously. Buildings should be constructed to endure both normal wear and tear as well as natural elements such as hurricanes, floods, fires and earthquakes.

Resilience is the ultimate form of sustainability. What could be better for the earth than to continue using what is already in place? (This avoids the devastating impacts of demolition and disposal, production of new materials and the transportation needs to haul everything to and from the site.)

Resilience is also a matter of 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.

Today’s structures need to be adaptable to these changes to allow for a variety of uses down the line.

Four primary practices for doing this are:

  1. Consider the broader context: Design for community resilience by addressing the way people interact and depend on each other, the buildings they occupy and the infrastructure available to them now and in the future.
  2. Factoring the unexpected into the pre-design process: Determine the performance rating of the structure. What are the impending risks and how can the building be designed to withstand and adapt to those changes?
  3. Weigh performance with cost-benefit: In most instances, a more resilient structure will carry a higher value as a better long-term investment.
  4. Consider the health, safety and welfare of the public: Not only as an industry professional, but to meet insurance and liability issues

As a subcategory of these processes, an architect should consider how the building design represents a client’s needs and values.

Do spaces within the building relate to each other? Are places for entry, reception, breaks and other needs organically connected?

How does the building relate to its surroundings? What will be its impact on the local community and environment? A resilient design will bring more good than harm, and complement what is already there.

Other considerations are views, lighting, acoustics, energy use, comfort, use of materials (for both sustainability and durability), and flexibility of layout.

Security is another valuable point to consider given today’s social concerns.

Finally, how buildable is this project? All these factors must be weighed in balancing resilience with return on investment. In most cases, it does factor out well.

Longevity at work

There are two types of resilience, and both are intertwined:

One determines the likelihood of a structure withstanding a cataclysmic event, such as an earthquake or fire. The other speaks to a building’s innate longevity: how long will it remain a viable place to live or do business?

The various components of a building have clearly defined lifespans:[viii]

  • Kitchens, bathroom appliances, paint and floor coverings normally last between 10 and 15 years
  • Windows and flat roofs last about 30
  • And the actual shell, 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.”

Construction projects today are designed so they can adapt to meet future requirements, he said.[ix]

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.[x]

“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:[xi]

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

We are all familiar with horror stories of building failure due to faulty design, construction or materials.

California’s Northridge Earthquake of 1994 exposed the vulnerability of older wood-framed, soft-story structures to collapse under significant seismic shaking.

The Camp Fire of 2018 — California’s deadliest and most destructive wildfire — taught us more about building resilience to fire in our buildings and communities.

These and other disasters have served as lessons on addressing hazards before they strike.

The International Code Council believes that resilient communities begin with “strong, regularly updated, and properly implemented building codes.”[xii] The organization emphasizes a “community approach” to ensuring that not only individual structures stand, but that the neighborhoods they are in continue to carry on.

“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 ICC website 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.”[xiii]

Recognizing this, the U.S. Resiliency Council has created a rating structure to describe the expected impacts of an earthquake or other natural disaster on buildings.[xiv] It is the organization’s hope that public awareness of the safety of our built environment will save lives and lead to safer structures overall.

Materials

Man’s first buildings were constructed with natural materials found nearby: sticks, mud, leaves, animal pelts, even snow.

The advent of concrete and steel revolutionized the building process and launched the advent of multi-story buildings.

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