According to most green advocates, green buildings must be durable. Alex Wilson memorably summed up the case for durability in an Environmental Building News article titled “Durability: A Key Component of Green Building.”

There are a few problems with the durability thesis, however: some durable buildings aren’t green, and many green buildings aren’t durable. In fact, the more one looks into the issue, the harder it is to find a link between durability and greenness.

What’s the Correlation?
One easy way to disprove any generalization is to provide counterexamples. As it turns out, plenty of durable buildings aren’t green, including:

• The Hearst castle in San Simeon;
• Buckingham Palace;
• Versailles.

On the other hand, plenty of green buildings aren’t durable:

• Hippie houses made from salvaged materials;
• Yurts or gers;
• Tipis;
• Old-time Alaskan log cabins;
• Third-world favela shacks.

One might perceive a trend in these examples: when it comes to greenness, size matters more than durability.

Living Lightly On the Planet
Most of us are trying to reduce our carbon footprint and our environmental impact, and some of us worry that our American lifestyle is unsustainable. In the back of our minds, however, we hope that a greener future won’t require us to give up our current luxuries. That’s why we rarely look to the Third World for architectural models.

Most traditional shelters are relatively small, use local materials, require very low inputs of energy, and cause little if any environmental damage when the shelter is abandoned. For those of us who came of age during the 1960s, the landmark book documenting indigenous homes was Shelter, the 1973 classic by Lloyd Kahn. As the examples provided in Shelter made clear, to live lightly on the planet, there is no need to build a durable home.

For most of the world’s population, building a house starts with scrounging local materials — stones, mud, cardboard, bamboo poles, discarded pieces of sheet metal, and, if one can afford it, a little cement. As a family gets more prosperous, such shelters are often improved and enlarged.

American readers may balk at the idea that U.S. homes could be anything but durable. But there are cogent reasons to consider the advantages of adopting materials and methods that aren’t durable:

• Durable materials are usually expensive.
• Tastes change. Few Americans like the look of the kitchen cabinets they chose ten years ago.
• Families change size, with new members being added or subtracted all the time.
• Americans are mobile; on average, we move every seven years. It may be more important for a house to be compostable than for a house to be durable.

The Advantages and Disadvantages of Durability
There are, of course, several strong arguments in favor of durability. As long as durable details are affordable, a building should be built to last as long as possible, if only to save oneself the hassle and expense of frequent repairs and rebuilding.

Moreover, since adequate insulation — a prerequisite for energy efficiency — is relatively expensive, it needs to be protected (if possible) with a durable shell.

Considering these advantages, why not legislate durability? We could, for example, require every home to be built with details designed to last two centuries. Would anything be wrong with this approach? Well, maybe:

• Very durable homes require the use of materials that are expensive to manufacture and transport.
• Since the needs of future generations are unknowable, it’s better to be humble about our ability to dictate where and how our descendants will live. Throughout history, many durable neighborhoods — from Fatehpur Sikri to Machu Picchu — have had to be abandoned.
• Durable buildings can be hard to retrofit when environmental necessity or new technology require remodeling. For example, energy upgrades of elegant European buildings are challenging, unless one is willing to cover up their beautiful stone façades. Builders of any era have no way to anticipate future changes in technology or environmental circumstances.
• Durability is arrogant, because it dictates our aesthetic tastes on future generations. How do we know that our buildings will seem beautiful to our great-grandchildren? Surely there’s no reason for ugly buildings to be durable. Having been built of poured concrete, Boston City Hall is certainly durable — but it is a loathsome and depressing addition to a handsome city.

During the 1990s, tens of thousands of suburban developments sprang up in arid parts of California, two hours by car from the nearest job. Urban planners now predict that these neighborhoods will turn into the slums of the future. Although the developers who built the homes were responding to a strong demand, the homes appear ill-advised in retrospect. Should these homes have been built with durability in mind?

Of course it’s easy for environmentally savvy planners to scoff at short-sighted projects in the deserts of California or Arizona. But even sophisticated green developers may be wrong in their predictions of where and how the citizens of 2109 or 2209 want to live.

Summing Up
I’ll admit that I’ve been taking a devil’s advocate position that is deliberately provocative. I am serious, however, about the need for philosophical consistency. Honestly requires us to admit that there’s no correlation between the durability of our homes and a commitment to living lightly on the planet.

A few takeaway points:

• Durability may be a virtue, but it is not an absolute virtue. Many other aspects of green building are more important than durability.
• Since we’re facing a global climate crisis, our proposed solutions should be conceived with a global perspective. That requires us to consider not only how we want to live, but also how others in poorer countries are living today.
• Although many U.S. architects and builders are working to design large energy-efficient houses, few are proposing low-energy lifestyles that might include small, inefficient shelters like trailers. We should all strive to lower our energy consumption — a goal that doesn’t necessarily require an energy-efficient house.
• Small, quickly built homes that last only 25 years are not inherently evil — especially if they can be built without the purchase of expensive new materials and if their residents don’t consume much energy.

After all, a shelter needs to last only long enough to fulfill its intended purpose.