A thoughtful tomorrow for timber construction

That we had better be circumspect about our future should be commonplace by now. Where do we find the finest examples in architecture of a thoughtful approach, we ask ourselves in several of the following newsletters? This time we end up with engineer-architect Bruno Deraedt, co-founder of BAST architects & engineers, who has also been teaching regenerative design for architecture students at KU Leuven in Belgium, since the beginning of the current academic year. Deraedt is best known as a man with a particular fondness for, and a deep knowledge of timber construction.

“With me, everything starts through a great love of nature, which means I design as ecologically as possible. So you soon end up with an emphasis on timber buildings and the calculations that come with it. I estimate that 80 per cent of BAST architects & engineers' work consists of wood or a combination of wood with concrete or brick. Only where there is no other option, other materials are chosen, although in each case the emphasis remains on a commitment to social sustainability”, the man opens before we have even half-heartedly asked a question, speaking to him at the crack of dawn. “We need to move towards a society where the emphasis is no longer on consuming, but adding useful things for people and the environment. Then you quickly arrive at the ‘regrowable’ material wood, which you can also reuse several times if you treat it thoughtfully.’

Targeting architects and contractors

For Bruno Deraedt, it is particularly important not only to show his fellow architects how he thinks things can be done differently. He also targets contractors, to whom he often gives evening classes and whom he reaches through various lectures. Such as during a series of lectures on timber construction for the Belgian building association Bouwunie. He is also in the process of developing a new company - ‘SymBioBouwSchap’ - to deploy this knowledge directly in projects or with other construction professionals.

“Among other things, I pass on how I notice that in recent years there has been increasing interest in working with wood, where previously it was mainly stone. The reason is well known, wood stores CO2, which reduces emissions of this greenhouse gas. Moreover, I try to convince the architect that wood is simply a material you can manage with a high level of craftsmanship. You can use it with attention to aesthetics and mould it to your own ideas, which is great, right? Moreover, you can also hide it visually in projects if you are purely after strong sustainable features. I see an additional advantage of wood in commissioning architects. There is so much that can be prefabricated, you can fully prepare the building process in advance in BIM, together with the contractor. So you no longer have to follow classical thinking, where you always start with bricks and only later think about the next step. What many also forget is that construction times are generally much shorter due to this way of working, which means you and the client are facing a shorter process with less impact on the environment. And perhaps most importantly of all, wood is a material that fits perfectly with the ever-increasing focus on renovation. Because of its lightness and ease of incorporation, it is very easy to work with, always with a regenerative idea in mind. Don't forget that renovating real estate also means retaining energy once put into it. Thanks to wood, we revalue this energy."

Building system Woodular

A good example of what the future of timber construction can look like can be seen in the recent projects BAST has collaborated on: circular building systems where movable and interchangeable units or building elements in wood are deployed in the rapidly changing society and needs. These include the Mobble (and the slide-in house), the Structurez structure with Circuwall panels (with Wood-inc) and Woodular (with the Flemish company De Noordboom). Each in a route apart with each system having its own individuality.

With the De Noordboom cooperative, specialising in carpentry and joinery, they developed an innovative building system called Woodular. This building system is completely modular and can be viewed in a demo house in Ronse.

“If you look at the Woodular, for example, you will find a fully modular adaptable system of building elements. This building system meets all technical regulations. This makes it usable for different purposes. So not only private housing construction, but also temporary applications such as garden offices, care units, classrooms, homeless and refugee shelters ...”

“Woodular illustrates how you can contribute to a positive environmental impact. After all, this is a modular and circular bio-based building system, which flexibly combines prefab building elements into modules that can be interconnected in various configurations. Moreover, all building elements within a module are interchangeable and can be reused, thus retaining their value. The result: buildings remain easily adaptable and expandable according to changing needs and available budgets. In addition, the materials used are chosen with a view to a sustainable future: the frame is made of wood skeleton and the insulation materials are ‘regrowable’. This approach results in a highly energy-efficient building that stores CO2. It fits beautifully into our story of going back to basics and designing buildings whose design requires less technology.”

Nursery ‘Het Wiegelied’ in Ostend

Another project that reflects the BAST approach well is one from several years ago in the Belgian coastal town Ostend. In what the locals call ‘the queen of the seaside towns’, they designed the ‘Het Wiegelied’ nursery (Wiegelied meaning lullaby) using the prefabricated method. Here, the city council opted for wood and bio-based insulation material in a project tackled together with the company Furnibo (based in Flanders, in Veurne) and ‘Puur Bouwen’ for bio-based prefabrication. Specifically, it concerns a day nursery for 72 children, divided into four living groups of 18 children with shared sanitary facilities. The building has ancillary offices, a multifunctional atrium, a kitchen, washroom and staff areas.

“This is a building that develops its functions largely on the ground floor, with only staff areas on the first floor. There was already a nursery on the plot, which was partly demolished. The implantation of the new building promotes a very flexible site utilisation, as it allows both a total demolition of the existing building and a future extension, which can fit perfectly with the new nursery”, Bruno Deraedt explains. “At Het Wiegelied, we optimised the architecture according to the importance of the health of the small users. We erected a building according to bio-ecological principles, relying on material choices and energy concepts with the most positive impact on human health and the environment. We started from a timber frame, with an infill of straw and lime hemp. We finished the straw construction walls with a lime plaster, and for the lime hemp walls we opted for an accoya veneer board. Furthermore, all façade materials have a long lifespan and require only limited maintenance.”

Future modular construction

We return briefly to modular construction. How does Bruno Deraedt see the long-term future for this?

“It is clear that this is becoming more and more common, especially in the city, where you score with it just by reducing working time and high site nuisance. There are still things to come in this prefab market, though, of which we are only experiencing the first phase. In the future, renovation will be about much more than sprucing up, it will revolve around adding elements or even creating something completely new in place of the old building. Think, for example, of so-called slide-in houses (Mobble) that take the place of a former row house in barely a few weeks.”

“What is certain is that there had better also be a change in mentality. There needs to be a realisation that the future is not about renovating cottages individually, but that we need to start thinking about collective solutions. How this is to be done must become the subject of a social discussion yet to be held. And daring to question the mainly Flemish mantra that your own house is your insurance for retirement. For me, the future is not in the classic individual way of thinking, we must above all also look at what can and cannot be cooperative.”