Studying old methods for future sustainable construction

IMAGINE THAT YOU ARE GOING TO REPLACE the façade of your house. You go to a builders’ merchant and find something called ‘exterior panelling’. You probably have no idea what kind of wood you have chosen, or what its properties are. All you know is that the panelling you have just bought has a quality label.

– Today, wood has become a standard material and there is a kind of disconnect between the forest and the product, says Géraldine Brun.

Géraldine has been a doctoral student in conservation at the University of Gothenburg for a year. Her doctoral project addresses sustainable construction, with a focus on exterior wood panelling. Conservation was a relatively new field for her when she started, but she already had knowledge about building houses – she previously worked as a carpenter and has a degree in engineering.

– I’m interested in seeing how we can use traditional knowledge in the modern world to build more sustainably. 

DURING THE PAST YEAR she has had time to study older building façades around Västra Götaland. Scandinavia has a long tradition of using wood panelling on façades. The buildings she has studied were built prior to the 20th century, when this panelling was still manufactured locally. Pine façades were used in Sweden at that time, but there are also relatively old exterior panels made from spruce. Alderwood – probably untreated – has also been used for façade cladding. On paper, alder does not appear to be a good material for outdoor use, as it has low durability and rots easily in contact with the ground. So why was it used in the past?

– They may not have had much choice. Alder grows fast, and can be found everywhere.

BUT IF ALDER LACKS good properties as a façade material, how have these old façades survived? This is one of the questions Géraldine has asked herself. Perhaps this type of wood works better than we think for façades. Much of what used to be common knowledge is now some- thing that few people are aware of. Old methods tend to be replaced by more modern, large-scale solutions.

– Today, we modify wood in various ways to make it last better. But what do we really want? Do we want wood that lasts 500 years, from a fast-growing forest?

A building’s façade cladding serves several purposes. Apart from the obvious one of providing external protection, the façade also has aesthetic qualities. This is just as true today as it was in the past. The façade makes a significant contribution to the architecture of the building, and today entire façades are replaced unnecessarily, just to give the building a different appearance or because the panelling looks old.

THE SAME APPLIES WHEN a small part of the panelling is discoloured and needs to be replaced, so the panelling is replaced on the entire building. So it’s not enough just to think about how to make the façade last as long as possible, according to Geraldine.

– There’s no point in finding a good way to give the façade a long life if that’s not what people want.

As well as her local studies, Géraldine has also researched wood panelling in France. In the Champagne region, people have been cladding their houses with wood for many years, traditionally using oak panelling split with an axe. But as production techniques evolved, they stopped using oak on façades. Was it a shortage of oak that led them to use other types of wood, or could they make more money by exporting oak to other countries? Or was it simply that splitting oak with a circular saw didn’t work as well?

– Which came first? It’s a shame we don’t know why this happened. It’s important to try to have tradition bearers and practitioners who ensure that we learn from what has been done. Otherwise we’ll be forced to try again and make the same mistakes.”

How can we use traditional knowledge in the modern world to build more sustainably

Text: Camilla Persson
Photo: Malin Arnesson