Hur kan träindustrin bidra till ökad cirkularitet och samverkan i byggandets värdekedja? Övergången från en linjär ekonomi till en cirkulär ekonomi innebär utmaningar och det är svårt att veta var man ska börja. Kan industriellt producerade trähus ge svaret på hur en sådan process kan se ut och visa hur vi kan bygga idag för att återbruka mer i framtiden och därmed spara på planetens resurser?

Mapping of biogenic carbon flows in the forest-based value chains in Sweden

The sawmill and wood industry sector is characterized by a high proportion of the use of domestic raw materials, where only around 2% of the timber comes from imports. 2950 kt of carbon is exported, which can be compared to the domestic use (including for energy purposes) of 8720 kt of carbon. Of the primary raw material used in the sawmills, 28% ends up in sawn spruce (2280 kt of carbon) and 18% in sawn pine (1460 kt of carbon). The sawn timber is then sent to the construction trade or for further processing within the wood manufacturing industry into various construction products, as well as to the furniture industry. The remaining portion of the wood raw material in the sawmills becomes by-products that go to energy production or to the pulp and paper industry.

From the Swedish wood manufacturing industry, there is a flow consisting of by- and residual streams where the majority becomes return wood chips (RT chips) that are either burned in their own boilers for heat production at the industry or sent to heating or combined heat and power plants. The amount of RT chips that enter the Swedish power and heating plants annually amounts to 1300 kt of carbon. The difference between what goes into the wood manufacturing industry and what is energy recovered in the form of primarily RT chips is bound in long-lived products such as wooden frames, building interiors, furnishings, and furniture, which are also partially exported.

The market for reuse and recycling of wood within the construction sector is still underdeveloped in Sweden, pilot studies are ongoing, and only small amounts of timber flow in this process. Since construction products often have functional and quality requirements that need to meet current building codes upon reuse, reuse is complicated, and the issue of responsibility also complicates matters. Regulations, test methods, new actors, and business models need to be developed.

There is a clear potential to use by- and residual streams from the wood value chain more efficiently considering the increasing competition for wood raw material from the forest. Two clear tracks

• Capture juvenile fibers from the breakdown and postprocessing processes in the wood value chain and coordinate flows into volumes that can be utilized for products instead of energy production. This requires coordination of more sectors than just the actors in the forest sector to find the right biogenic raw materials for energy production.

• Develop processes, methods, and business models that contribute to RT chips being used to a greater extent for products instead of energy production. A prerequisite for change is that both industry and society's energy supply (electricity and heat) can be managed with less energy from combustion of wood raw material.

Among the actors in the value chain, there is an understanding and even a willingness to make a transition, but above all, there is a lack of economic incentives to do so.

A further perspective, given the increasing competition for wood raw material from the forest, is to reflect on the volumes of exported wood, its use, resource efficiency and possible national need.

Today, there is a significant lack of detailed public statistics and data on the amount of sawn timber that goes into various types of products. The risk of disclosing company- that data collected by, for example, SCB (Statistics Sweden) cannot be published officially. Not all companies report data either. Statistics are available for flows upstream for sawmill production and downstream for distribution. Individual companies in the value chain have good knowledge of their internal flows. Statistics for product categories within wood manufacturing are specified at the product level and not in the level of detail for the input material. The low resolution makes it difficult to compile reliable statistics for flows of wood-based material. For energy and heat production, statistics are available via Energiföretagen (Swedish Energy Companies) and industry organizations. However, there is currently poor knowledge about the material flows that go to RT chips, which then go to combustion. A further perspective, given the increasing competition for wood raw material from the forest, is to reflect on the volumes of exported wood, its use, resource efficiency and possible national need.

När en byggnad rivs skickas det mesta av virket till förbränning och energiåtervinning. Tänk om det i stället är möjligt både tekniskt och ekonomist att använda en del av virket för att industriellt tillverka fasader av återvunnet trä till nya hus! Tillsammans undersöker branschen och forskare möjligheterna för att använda återvunnet trä på ett lönsamt sätt.

The implementation of computer design within the building industry has created new possibilities for creating digital tools for users such as architects. There is however a lack of easy to use, efficient digital tools to aid and explore design alternatives for architects when using products within the wood building industry. This paper demonstrates how a modular facade system in wood can be adapted for facade configurations in different contexts by using computational design. The goal is to develop a digital design tool that is easy to use and provides the architect with a high degree of freedom to create project-unique facades. The design tool is developed with computational design methods for flexible and adaptive design. In parallel, assessment is made that the design solutions can be manufactured smoothly and quickly via digitalization and industrial production. The result of this research shows that the façade system can be customized by using parametric programming methods, and thus enable architects to design facades for different contexts. The design tool was verified with the architect partners concerning usability and manufacturers concerning production.

Hur kommer framtidens byggande att se ut? Forskningsinstitutet RISE och IVL Svenska miljöinstitutet genomför tillsammans med industriparter ett projekt för att studera återanvändning av träbyggnader i en cirkulär ekonomi. Projektparterna har bland annat arbetat med två demonstratorer där trähus ska kunna ändras, flyttas och byggas på efter behov.

There is a need for a shift towards circular economy in the building and construction sector. Design for deconstruction and reuse (DfDR) and design for adaptability (DfA) have been suggested as means to facilitate reuse of buildings and diminish waste and material consumption. A standard, ISO 20887:2020, has appeared to support the implementation of DfDR/A. One objective of this study is to demonstrate timber building design examples that can be considered consistent with the standard and designs that should be avoided. Another objective is to examine if there are important aspects of DfDR/A for timber buildings that are insufficiently covered by ISO 20887:2020. The broader, long-term aim of the work is to remove thresholds to DfDR/A by providing support for designers and industry in applying the standard. The principles and strategies in ISO 20887:2020 are illustrated with practical examples from case studies, organised in a searchable database.

The objective is to demonstrate the co-operative design (co-design) and production development process of a new wooden façade system. Today, architects and designers are seldom involved in the development process when designing new products within the wood building industry. The architect and the actors in the wood value chain are far from understanding their respective standpoints in new product development, thus creating a gap. This gap between actors hinders innovation and can mean that valuable design knowledge and methods are not used that can promote innovation in the wood building industry. In this paper we demonstrate how the development process of the façade system is profoundly influenced and improved by incorporating knowledge of the design process. Product development is becoming more and more complex and therefore more knowledge intense. This was addressed by working in parallel with partners coming from different areas of expertise, resulting in a co-design process considering aesthetic and functional requirements as well as the industrial manufacturing processes, interactively, throughout the entire development process. Using co-design when designing an adaptable facade system has proven to enable assessment of complex requirements, resulting in a sustainable system that can ensure good quality on material, aesthetics, and functions.

There is a need for a shift towards circular economy in the construction sector and design philosophies as Design for Deconstruction and Reuse (DfDR) and Design for Adaptability (DfA) are being developed as means to design out waste and enhance resource efficiency. However, applying these philosophies is not yet common practice. The amount of DfDR/A timber buildings described in literature is limited. This study aims at increasing and spreading knowledge on DfDR/A for timber buildings. It has four goals: 1) To suggest methods to apply DfDR/A. 2) To suggest new design solutions. 3) To collect experiences on connections in relation to DfDR. 4) To suggest how guidelines for deconstruction and reuse can be formulated. The study presents three methods that all proved valuable in applying DfDR/A: one discussion-based method to improve an already existing timber building design, one indicator system to assess the DfDR/A potential of building designs, and one matrix to guide design decisions. We used the first method to conduct five case studies in four European countries. The studied designs were judged to be well or relatively well adapted for deconstruction and reuse already today. The fact that the studied buildings are all offsite manufactured and of modular composition benefits the deconstruction process, partly because construction and deconstruction are similar processes so that the knowledge and infrastructure that companies have can be directly transferred to enable deconstruction and reuse. Where large modules can be recovered, the time and energy needed for deconstruction as well as the risk for damage will be reduced. Disadvantages to deconstruction and reuse identified were typically linked to the complexity of building modules and that individual components are not independent. This was reflected as irreversible or hidden connections, inaccessible services, interconnected layers of the structural modules and many different component sizes. One of the case study buildings, designed with mass timber panels, excelled in the simplicity and reduction of number of steps required for maximum material recovery. New designs suggested included making fasteners more accessible to deconstruction, avoiding letting sensitive materials as plastic foils and particle boards pass continuously over joints between elements, and (for cases where standard units are not already used) standardizing elements. One case suggested using solid wood components instead of engineered wood products to achieve durability. The study showed that simple changes in design can lead to an augmented reuse potential. Some of the new design solutions generated will be taken into production by the participating manufacturers. Insights on connections included recognizing the fact that the use of reversible screwed connections is not sufficient to ensure deconstructability and that although nailed or glued connections severely complicate reuse of components, they might be accepted within elements in case reuse on element level is the target. Guidelines for deconstruction and reuse were developed in all case studies. Taken as a group of studies, there are advantageous additions proposed to earlier guidance documents. Despite being based on the same source, the different plans suggested varied substantially. There was a noteworthy difference between manufacturers’ in-house plans to those proposed by architects, engineers, or researchers, which speaks to the uncertainty regarding the appropriate structure and format.

This study reports on a deconstruction process followed on site, with the purpose of documenting experiences that can help us understand how to design timber buildings for future deconstruction and reuse. The deconstruction concerned three timber buildings built up by volumes (3D modules produced off-site). Modules were in good shape at the time of deconstruction except for some minor local moisture damages. They were all covered and transported to be reused elsewhere. Experiences made included that lack of information on the assumed deconstruction process delayed and complicated the work. A need for disassembly plans was highlighted, including things as order of dismantling, positions of lifting points, weight of modules and positions of screws and amount of screw used. Results indicate that simple, clearly visible joints and services, limit the potential problems and damages during deconstruction. The building should simply be designed to be taken down in the future, the amount of screw allowed should be clearly described and the number of attachments should be limited. Furthermore, the risk of burglary during deconstruction needs to be considered as this may cause damage and delay.

Fasadprojektet “Fasaden i staden Snabb, Snygg, Smart” är avslutat. Syftet med projektet var att öka marknaden för träfasader genom hållbara och flexibla fasadsystem med en estetik anpassad för stadsmiljö. Det nya fasadkonceptet i trä har utvecklats genom projektets omfattande studier och tester av material, design och teknik. Resultatet är ett system med färdiga fasadelement av furubrädor som är snabbt att montera och har en design som är lätt att variera.