By Patrice Frey

When we think about the built environment and sustainability, it can be all too easy to focus on the energy used to operate a building, or maybe even the energy needed to get to a building.  And of course it’s incredibly important to consider the energy needed to build a building.  But the issue of durability – how long our buildings last – typically isn’t given the consideration it deserves.

Yet how can a building be truly "sustainable" if it only lasts a few decades (or less) and then must be replaced?  I got to thinking more about this topic when I was able to spend some time in Oslo and Norway’s western fjords region earlier this month and see some of the country’s beautiful stave churches - some of which were built more than 900 years ago.

I was in Norway at the invitation of the  Society for the Preservation of Norwegian Ancient Monuments (Fortidsminneforeningen in Norwegian– try saying that out loud!), which asked me to attend and speak at a conference in Oslo on the intersection of sustainability and preservation. The event, called “Det grønneste huset” (The Greenest Building) brought preservationists, architects, green building advocates, and others from all over Scandinavia to talk about the environmental value of reusing buildings, and how to overcome perceptions about the difficulty of greening traditional buildings.

As part of my travels, my hosts took me on a tour of three historic stave churches. There are 28 of these churches remaining in Norway, beautiful medieval wooden post-and-beam structures that were constructed between 1130 and 1350. The name comes from the building technique of using load bearing corner posts (stav in Norwegian) resting on sills.  These magnificent houses of worship have survived centuries thanks to the incredible durability of the high quality old growth timber used to construct them, sophisticated traditional building techniques, and care and maintenance by the Norwegian people over time.

My visits to the churches got me thinking about a great explanation of durability I once came across, this one in Canadian Architect.  To paraphrase, a building can be thought of as durable when it survives long enough that the natural resources needed to build the structure have been regenerated.  A building made of timber, then, could be thought durable if it lasts the 75-100 years or so need to regenerate wood that was needed to construct it in the first place.

By that measure, the surviving Norwegian Stave Churches are not just iconic examples of the 2,000 or so stave churches that once dotted the landscape, but also monuments to durability that help all of us – Norwegian or not – understand what real sustainability looks like.

The Bourgund Stave church dates to 1180, and is the best preserved  of the stave churches.  The gables of the church feature dragon heads, similar to those used at the bow of Viking ships. Credit: Patrice Frey

The interior of the church is almost completely dark – windows were added to some of the stave churches in later years, but the Bourgund church has been little altered. This colorful lectern dates to the Reformation. Credit: Patrice Frey

Kaupanger Stave Church is believed to date to about 1150, with timber that was cut in  1137.  The church is still in active use. Credit: Patrice Frey

Beautiful windows – and weathering – on the  south façade of  Kaupanger Stave Church. Unlike Bourgund, Kaupanger features a number of windows  that were added in later centuries, providing for significantly more natural light in the interior. Credit: Patrice Frey

Urnes Stave Church is a World Heritage Monument. Constructed in 1130, it’s believed to be the earliest example of the stave church building type.  It’s been under the care for the Society for the Preservation of Norwegian Ancient Monuments since 1181. Credit: Patrice Frey

Now that’s recycling. The northern wall of the Urnes Stave Church features intricately carved panels that were part of an earlier church on the site. Archeologists believe that one or two churches existed on the same site previously. Credit: Patrice Frey

Patrice Frey is the president and CEO of the National Main Street Center. She was formerly the director of sustainability at the National Trust for Historic Preservation.