Architects turn to the old friend: wood construction is in high demand

New technologies, old traditions, environmental imperatives, cost concerns, the revival of ancient low-tech techniques… neither the building industry nor its future is simple. Delano spoke to members of the sustainable construction movement to find out what’s going on in this sector.

A new neighbourhood is under construction. Huge, prefabbed pieces of reinforced wood arrive to the construction site, each one cut to specifications predetermined by an AI program. The insulation is so good that a heating system practically isn’t necessary and, strengthwise, the wood composite rivals good old concrete.

Next door, another house is going up, this one made of pieces of clay–sourced nearby–that have been 3D-printed in a factory.

Both houses cost less to build than the once-ubiquitous masonry buildings in Luxembourg, and they cost far less to heat. Oh, and it takes just a few days to assemble their main structures onsite.

Wood: it’s happening

The above is, admittedly, a vision of the future–though only in part.

Wood is fast becoming an attractive alternative to concrete and for plenty of reasons. Most obviously, it stores CO2 and it requires neither tremendous amounts of fossil-fuel-generated heat (like steel does) nor a CO2-emitting chemical reaction (like cement, an ingredient in concrete, does) to create. Many people, meanwhile, are drawn to the back-to-nature aesthetic of wood, particularly as the oil- and plastic-dominated era matures into (hoped-for) obsolescence. Plus, studies have shown that looking at wood can lower your blood pressure.

None of that is new, however. What’s new is that the technology used to construct with wood has finally started to bring the cost down. This, at least, is the contention of François Cordier, CEO of Leko Labs. Over eight years and with a team of 50 people, Leko Labs has developed both a novel type of reinforced wood and an AI-powered software that can optimise how to use it.

That optimisation, i.e. minimising the amount of wood needed, was key for Cordier, since bringing the price down–as well as the value up, since the design results in thinner walls and thus more floor space–is what, he says, will make the difference for contractors. This approach is relatively novel too. As he explains in an interview: “[People] have wasted a lot of materials, even in timber construction, because the calculations are done according to antiquated methodologies and nobody has the proper software–so they are putting safety factors everywhere.” In other words, people buy and use more wood than they need.

Two architects from the firm Saharchitects, Sahar Azari and Stephanie Law, point to other factors that have also brought the price down. “[Building with wood] used to be more expensive,” explains Azari, “because we didn’t have enough labour, enough contractors who knew how to work [with it].” Nowadays this is less of an issue, she adds. “It’s more a matter of the price of lumber versus the price of concrete versus the price of steel.”

“[Wood] is not very energy-intensive,” Law adds, “which is making it a little bit more price-efficient now, compared to concrete and steel, which are very energy-intensive.” A related point, Azari adds–concerning not just wood–is a movement in Europe towards low-tech buildings that rely on traditional designs and insulation instead of on tons of expensive technologies.

Azari also confirms what Cordier said, that building with timber means thinner walls which results in more floor space. “So, imagine that building with timber is 5% more expensive than building with concrete,” she says. “But if you also get 5% more living space…”

Another door that has already opened for wood is the regulatory environment, which, according to the architects, is up-to-speed. Current techniques were developed in Austria some two decades ago, explains Law. “They did enough research back then to create the regulations.”

Currently, the tallest wooden building in the world is a 25-storey tower in Milwaukee, USA, finished in mid-2022. According to the Leko Labs website: “Virtually all steel and concrete above ground in a conventional building can be replaced.”