For about three years, Willy Naessens Industriebouw has been developing a concept based on circular construction. In Belgium, construction is mainly custom-made. “In order to build circularly and reuse industrial buildings and materials, we need to move towards standard materials and standard dimensions,” says CSO Kris Vanrenterghem.
On the one hand, we have the stacked commercial buildings that we focus on,” says Kris Vanrenterghem, Chief Sustainability Officer at Willy Naessens. “This is mainly due to the lack of space in ports and logistics environments. Increasing the height of the available space is often the only solution. In order to make such projects economically viable, it is important to look at the available area and the cost price of the land”.
Life cycle versus service life
“We also focus a lot on the circularity of buildings. Think of it mainly as the reuse of an existing building, where the lifespan is many times longer than the useful life of the building. This can be done in a number of ways. You can reuse the building blocks of a building by rebuilding it in a different location using existing materials. As a second option, you can keep the exterior of the building, but give the interior of the building a different function each time,” Vanrenterghem explains.
“In Amsterdam, we are doing a project that starts as a car park and can then be converted into an SME unit or office space. So the building remains, but inside the use changes. We know of very few buildings that have had the same use for a hundred years. Usually a building has the same function for 30 years and then people start thinking about demolishing it or rebuilding it from scratch. So people are still thinking too much in terms of use and not enough in terms of design life. That’s where we want to make a difference.”
Concrete and financial banks
“At the end of its life, we determine the waste stream. Concrete is a very valuable material. You can break it down and put it back into new concrete. And you can use concrete waste in road construction, for example. No residual elements of concrete go to waste. It’s a different story when you look at steel and wood. You can never recycle these materials 100%. Often 85% of the organic residues are incinerated,” says Vanrenterghem.
“Concrete also absorbs CO2. So there is a carbonisation process. Over a lifetime of, say, 50 years, top-quality concrete will absorb as much CO2 as it emitted during production. Once the CO2 is bound in the concrete, it is never released, not even during the recycling process.
“Financial banks only look at the economic cost. They do not take into account the useful life of a building for loan conditions. For a financial bank, the cost at the end of the useful life should be zero. But that is not true because the building still has value at the end of its useful life. Banks need to move with us and think about the sustainability story in the long term, not in the short term of thirty years,” says Vanrenterghem.
Standard sizes
“We could create a database of buildings and their materials. For a new building, you can then use this database to reuse old materials and combine them with new ones. In the interests of circularity, it is also important that we move towards standard sizes and elements and gradually move away from customisation. Solutions are always sought for the specific problems that arise during the construction phase, whereas when standard elements are used, there is a solution for every problem. Our current way of building in Belgium is very intensive and much more expensive because of all the customisation. The Danes and Swedes are many years ahead of the more traditional Belgians when it comes to circular construction.”
Strict standardisation
“Because we manufacture the concrete profiles ourselves, we can react very quickly to changing standards. Standards vary greatly from country to country. We are an international player and follow the standards of the strictest country. This way we know that when we put materials into production, they will be usable in most markets for many years to come”.
Vanrenterghem concludes: “It is difficult to determine the lifespan of a concrete building. Some sources say 150 years, but we don’t really know because there are no concrete buildings that are 150 years old. In those days people built with natural stone and certainly not with concrete. Concrete rot will undoubtedly occur after a long time, for example under the influence of the weather. At Willy Naessens Group, we have 40 years of experience in concrete construction. We are at the forefront when it comes to the total package of circular construction, but in fact all contractors should develop in this direction”.
This post Willy Naessens Group en circulair bouwen: “Op naar standaardmaten” – Flows first appeared on Flows news site, October 12, 2023.
Image credit: Willy Naessens Group