Rapporten redovisar data från projektet Energieffektiviserings- och klimatomställningsåtgärder med bevarade kulturvärden för medeltida kyrkors takkonstruktioner av trä. Projektet är finansierat av Energimyndigheten och leds av RISE, med Norsk institutt for Kulturminneforskning (NIKU) som partner. Projektets syfte är att stödja en förvaltning av delar av vårt äldsta bevarade träbyggande där energibesparingsåtgärder, energiomställningsåtgärder och klimatanpassningsåtgärder balanseras mot kulturvärden på ett sådant sätt att ett antal identifierade potentiella hot mot kulturvärdenas bevarande kan undvikas. Data som publiceras här ska kompletteras, bearbetas vidare och spridas på former som passar målgruppen - yrkesverksamma som på olika sätt kommer i kontakt med takkonstruktionerna och deras bevarande.

Energy saving potential in medieval churches: A preliminary study with dynamic energy calculation for a fictitious object In the project, Energy efficiency and climate change measures with preserved cultural-historical values for wooden roof structures in medieval churches, the following question has been raised: How much is saved by insulating the attic of a medieval church, in relation to other measures such as lowering the indoor temperature? As a first step in answering the question, a preliminary study has been carried out. A dynamic energy calculation has been made for a fictitious church. The effect of insulating was compared to the effect of lowering the temperature. The result shows that the most effective measure of those investigated is to reduce the indoor temperature. To get a clearer picture of which measures are effective for different geometric and geographical conditions, it is recommended that case studies be carried out.

Vägledning till förvaltning av medeltida kyrktak presenteras som en serie om sju filmer och sju planscher. Vägledningen vill uppmärksamma ett dolt kulturarv - de upp till tusen år gamla takkonstruktionerna av trä i svenska och norska medeltida kyrkor. Hur ska de bäst tas om hand i ett förändrat klimat och med krav på energieffektivisering? Vi ställde frågan till kyrkoförvaltare, hantverkare, konsulter och myndighetspersoner i Sverige och Norge och de delade generöst sina erfarenheter. Här har vi sammanfattat deras råd.

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.

Measuring deconstructability and reusability of timber buildings. Timber construction must - like all construction - develop towards better resource management. One way to reduce raw material consumption and waste production may be to reuse buildings and building components to a greater extent, and to facilitate this, buildings would need to be designed with that aspect in mind. A European project, InFutUReWood, has investigated how design adapted for reuse can be facilitated and has identified a need for a tool for assessing the deconstructability and reusability of timber buildings. A basic first sketch for an assessment tool was produced, and this study takes the work with the tool further. The overall purpose is to support a development where reuse is considered already in the design phase. More specifically, the project develops a tool to assess how well deconstruction and reuse have been considered in the design of a timber building. The tool is based on the international standard ISO 20887: 2020 and on case studies. The project seeks to answer the questions: What makes deconstruction and reuse easy and what makes it difficult - according to case studies? How can these experiences be considered in the design of the assessment tool? What development needs are there for the sketch of at tool? The work has three thematic parts: 1) Analysis of dismantling and reuse processes in case studies. 2) Analysis of an existing draft of a tool. 3) Assessment of how the tool could be further developed. The general methods of the work are result analysis, interviews, photo documentation and studies of drawings and construction documents. The case studies show several practical ways to achieve dismantling and reusability and illustrate how ISO 20887:2020 can be practically applied. To make the tool suitable for use by an independent party, it needs to be simplified and the assessment criteria processed to be more objective. Clues to how the indicators can be developed are obtained. Continued work includes the involvement of industry to develop criteria that will make them have confidence in the tool. A reformulation and new formulation of indicators in the tool and validation of these is also needed.

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.

Vertical extensions and heritage values The construction sector entails a significant environmental and climate impact, with large raw material consumption and waste production and huge emissions of greenhouse gases. More sustainable ways of meeting our need for buildings can include prolonging the life span of buildings. This requires buildings to be flexible and adaptable to changing needs. The Timber on top project investigates how vertical extensions to existing buildings can achieved in a way that is sustainable socially, ecologically, and economically. The broader aim of this study is to support sustainability in the building and construction sector. The goal is to map and compile practical knowledge on how heritage values are best considered in vertical extension processes. Methods used are literature studies, a workshop, and interviews. The results show that obvious parts of a good practice are to involve competence on building conservation in the process, to follow up and control heritage values in the construction process, to ensure that there are control points in the control plan and that these are followed up. Specifically, different advice can be given for different stages in the construction process. Best practice in the idea stage Examine the conditions of the object already in the idea stage. Contact an antiquarian early for informal advice. Examine whether the object is sensitive or not and whether it is a house that is suitable to extend vertically or not. In connection with pre-study work, carry out an investigation on the object’s heritage values. Let the antiquarian take part in various investigations that are made. For extension projects, it is especially important to also have a structural engineer involved early in the process. Superstructures can lead to several types of measures that affect heritage values: reinforcement of load-bearing parts, measures for fire protection and measures for noise protection. At an early stage, different design alternatives can be explored, and technical requirements and cultural values can be weighed against each other. Hire an antiquarian who gets an integrated role of sounding board in early investigations and who can support an architect. Best practice in the planning stage and implementation stage Initially, when the consulting group is put together, make a presentation of the building and its heritage values. Take a tour of the site with everyone involved. Strive for continuity in the consulting group to avoid recurrence in the dialogue. Bring all important skills with you early. Include an antiquarian in the implementation phase. Checkpoints must be followed up. Contribute to the expert antiquarian coming out on the construction site to follow up the control plan. Strive for a good dialogue, where all interests come together.

The building sector accounts for a large raw material consumption and waste production. One way of diminishing these would be to reuse buildings and building components to a higher degree. To facilitate that, buildings would need to be designed with that aspect in mind. Work Package 2 of the InFutUReWood project investigates new ways to design timber-based structures. This study investigates how new design concepts can be developed to make Villa Anneberg, a two-storey light timber house from the Swedish manufacturer Derome, adapted for deconstruction and reuse. The objectives are: • To identify the inherent strengths and weaknesses of the current design of Villa Anneberg regarding deconstruction, rebuilding and reuse. • To show how the design could be improved with respect to future deconstruction and reuse and to estimate the amount of wood that could be reused in the future with the current and the improved designs. • To suggest guidelines for deconstruction and reuse. • To test and develop a method for carrying out case studies, as the study is the first in a series of case studies treating different structural systems. The study is limited to the load bearing structure of the building. Focus is on reuse rather than recycling. Methods used involve interviews, structured meetings, analyses of drawings and documents, photo documentation and design work. A reuse scenario was assumed where the building will be deconstructed after a few decades into its separate parts. It will then be transported and reassembled to an identical building in the same geographical region. It was found that the current design of Villa Anneberg is relatively well prepared for this scenario already. The building is designed for efficient transport and assembly and the process is judged to be reversible to a high degree. Many connectors are screwed, and the building can be deconstructed with common and simple tools. Several weaknesses were also identified. Among these were joining techniques that are not reversible. Modified versions were developed for three joints. The new solutions were achieved with relatively small adjustments in design and within existing technology. One of the new connections was found so economically valuable to the manufacturer Derome, that it is likely to be taken into production soon. We estimated that the proportion of wood that is reusable would be higher for the modified Villa Anneberg than for the current. The proportion wood that is reusable in the load bearing structure with current design is estimated to 82,7 %. The proportion of wood that is reusable with the modified design is estimated to 86,4 %. These figures apply to the studied scenario. Guidelines for deconstruction and reuse were suggested. The case study method was found efficient and ready to be used in further case studies.