"By reusing more and being able to think of more uses than the primary of the material, we can together approach a more circular economy."
Reuse and wood construction
Wood is a renewable material that lends itself well to circular construction. Wooden structures, such as beams and roof trusses, can be reused either in their original condition or after minor alterations or repairs. A wooden structure can undergo several stages of circular use. First, the structure can be used for its intended purpose; then it can be reused; subsequently, it can be recycled (for example, into chipboard); and finally, it can be used as biofuel. This process helps to reduce waste and save resources over a long period of time. Additionally, wood has a lower climate impact during manufacture than concrete and steel.
However, some sceptics argue that circularity and timber construction do not always go hand in hand.
The RISE research institute is working on several projects that prove the opposite. Karin Sandberg, a senior researcher at RISE, is someone who really knows what's going on. She works on developing wooden structures adapted for circular flow, investigating how best to enable their dismantling, reassembly and reuse. Here is how she responds to some of the preconceptions that exist in the construction industry.
MISCONCEPTION #1
It is not possible to reuse materials from wooden houses.
"I would argue that we often underestimate wood. Wood ages with dignity and holds up very well over time. It can be used repeatedly, both as whole components and as a raw material. That's how it was done in the past. Of course, we need to carefully check quality and strength, especially where requirements are high. However, checking is not an insurmountable obstacle; methods can be developed for this.
More standards are also being introduced to facilitate sorting and quality control, both in Sweden and internationally. Technically, it is therefore possible, and research confirms that the material can continue to function. The challenge lies in the fact that we do not always have the necessary systems or habits in place, but developments are moving in the right direction."
MISCONCEPTION #2
No one wants to reuse old building materials.
"This is not true at all. Many people are interested, including building conservators and companies working on modern construction projects. Many people are already reusing doors, window frames, entire floors, and beams. We are also seeing more reuse hubs and digital marketplaces opening where you can buy and sell materials.
This is a rapidly growing trend. Sometimes, reuse requires adapting the design to the available building materials, but this can also give buildings more character. I feel that circular thinking is really starting to become a natural part of how we plan and build."
MISCONCEPTION #3
It's so difficult to dismantle wooden buildings that it's not worth it.
"I won't deny that it can be complicated, but just because something requires extra effort doesn't mean that the result isn't worth it. The important thing is that it is entirely possible and often even economically viable to reuse entire wooden buildings. We have examples where entire buildings have been dismantled and moved, such as the temporary Östermalmshallen, which after five years in Stockholm was rebuilt in Västra Götaland as a padel tennis hall. This clearly shows that it can be done.
In cases where dismantling can be planned from the outset of construction, it is also considerably easier. It is therefore important to establish correct dismantling and reassembly plans today, which we at RISE have done in the project ‘Design of the future – reuse of wooden buildings in a circular economy’. The resistance, difficulties and cost-increasing circumstances are more about a lack of knowledge than actual obstacles. When you know how to dismantle, store, transport and reassemble, it is not an impossible project at all."
MISCONCEPTION #4
Planks with nails or screws cannot be used again.
Yes, they can be used, but the material must first be processed. The nails and screws need to be removed, which is labour-intensive, but manual and mechanical methods are available for this task. In one of our projects, 'DUET: Circular Design and Use of Wood Building Elements', we cleaned the studs of nails that were used in the wall elements of timber from a demolished municipal building.
In the ‘FÅTT – Processing of Reused Wood through Technology Development’ project, we developed wooden façades from industrial waste material and demolition timber. The material can be planed, or shorter pieces can be joined together to form longer elements — for example, by finger jointing. Holes left by screws and nails usually have no effect on strength. Aesthetically, you can either adjust them or leave them visible. What matters is not how the wood originally looked, but how you choose to process it.
In the project "FICK - Refinement of Reused Wood through Technology Development" we have developed wooden facades from industrial residual material and demolition timber. You can plane the material or join shorter pieces into longer elements, for example by finger jointing. The holes after screws and nails usually have no impact on the strength and aesthetically you can either adjust them away or choose to actually let them show. The important thing is not how the wood looked from the beginning, but how you choose to process it.
MISCONCEPTION #5
It is not possible to get recycled wood
aesthetically pleasing.
"I think people really need to rethink this. Recycled wood can be incredibly beautiful. We have planed, shaped and profiled old timber to create completely new designs, with both smooth surfaces and more textured finishes. Currently, three facades are being prepared for the ACE (Arctic Centre of Energy) Powerhouse in Skellefteå: two from recycled wood and one from industrial waste. They are aesthetically pleasing and technically robust. There are times when you want the wood to look almost brand new, and other times when you want it to show signs of its history. Both are equally valid choices. The important thing is to know how you want to use it and to be bold enough to try."
Final words from Karin:
We must become better at reusing all building materials efficiently, not least wood. If we reuse more and think of more uses for materials than their primary one, we can work together to move towards a more circular economy. Unlike many other building materials, wood can be reused in its original form — for instance, as beams, panels, or entire building modules — without being melted down or broken apart. I also believe that wood lends itself particularly well to what we call 'design for disassembly', whereby buildings are constructed in such a way that they can be taken apart and the parts reused in new constructions. This means that a house can be seen as a store of materials for future construction projects.
I believe that the future of timber buildings lies in thinking in a circular way when ordering, designing and constructing buildings. This means that assembly and disassembly become two equally important parts of the same process. We need to plan for how we can dismantle, stored and reassemble a building, perhaps far into the future. Wood is a material that can do this, as historical buildings have already proven.
Therefore, the question is not whether we can, but how early we start thinking about it. This is where the major development work is currently taking place. I think it feels hopeful.
In terms of definition, reuse, recycling and recovery are different things.
Reuse and recovery involve using a product again, either in its original condition or after minor alterations, without breaking it down into raw materials first. This may involve repairing, renovating, or adapting the product for a new function. The aim is to extend the product's lifespan and reduce the need for new manufacturing, thereby saving resources and energy. Recycling, on the other hand, requires the material to be processed and converted into new materials.