As the built environment moves towards more sustainable and circular practices, the role of daylight in these strategies remains an underexplored area of research. This workshop will explore how daylighting principles can contribute to a Circular and Sustainable Built Environment, such as through the reuse of buildings, façade components, windows, and glazing, while considering relationships and impacts on daylight performance and qualities, design process, energy use, and human comfort and health.

Recent research has started bridging this gap, demonstrating how solar-responsive and adaptable façades can optimize daylight while enhancing the circularity of facades in urban environments undergoing urbanization and densification. However, further investigation is needed to understand the interaction between daylight and circular construction practices, including adaptive reuse, reuse of building components, glazing, and material recovery.

Objectives

• Identify various daylight and circular strategies and their interaction/integration.
• Explore the influence of coupled daylight and circularity strategies on building performance, visual comfort, and health effects.
• Discuss daylight properties and qualities of reused buildings, façade components, and glass versus new high-performance buildings and components.
• Identify the next steps and define possible outcomes.

This research outlines the processes and methods applied in the ReCreate project for transforming deconstructed precast concrete elements into reusable secondary products. Drawing from real-life pilot projects in four countries, the task was to examine and test procedures for stripping, cleaning, cutting, and retrofitting reclaimed components, such as with new connectors, to meet the requirements of new structural designs.

These processes are implemented and evaluated across the project’s pilot cases in Finland, Sweden, the Netherlands, and Germany, using a variety of wall, slab, beam, and column types that were not designed for deconstruction and reuse. The processing steps include the removal of surface layers such as plaster, paint, wallpaper, adhesives, and wiring, as well as surface cleaning with mechanical and chemical methods. Health, safety, and environmental considerations guide the selection of techniques, including dust control and the responsible handling of solvents and equipment. Refurbishment tasks such as cutting and retrofitting with novel connectors are discussed in terms of digital workflows, leveraging interoperable formats like the IFC, supported by optimization algorithms that solve the optimal cutting problem. The goal is to minimize waste and maximize reuse potential.

Some of the processing tasks were conducted at factory premises or directly on-site, depending on logistical and technical feasibility. Data from pilot projects document the process, from stripping and refurbishment to element handling, protection during transport, and final reuse. The findings demonstrate the viability of converting structural components from existing buildings into re-certified elements for new construction and contribute to scaling reuse within circular construction practices.

Buildings significantly contribute to climate change. Reusing structural components from buildings, particularly concrete—the most widely used construction material—offers a promising pathway within a Circular Economy to reduce this impact. However, demonstrating the feasibility of this approach and investigating supportive methods and tools is essential. Therefore, our research focuses on the reuse of precast concrete, aiming to reduce its carbon footprint and advance sustainable construction practices.

This study proposes a concept and workflow for solar, context-adaptive and reusable facades. Integrating solar control with parametric facade design, the workflow uses solar radiation to inform facade modules with variable openness or properties (e.g. frit cover), enabling envelopes to adapt to urban context changes while promoting circularity. The method was tested through simulations, assessing daylight, glare, energy and circularity in changing urban scenarios. A Solar Circularity Indicator (SCI) was introduced to track façade alterations and reuse. In the 100 m new obstruction scenario, 79% of facade modules were maintained, while 29% of altered modules were reused, yielding an 85% SCI. Sunlight Autonomy metrics aligned well with SCI. Re-design improved Spatial Daylight Autonomy by up to 4% with minimal energy increase (<1%). Our solution provided 2% more useful daylight (100–3000 lux) than glazed facades and 11% less glare. The workflow provides a framework for circular, performance-based designs that preserve aesthetics and adaptability.

This research presents the outcomes of Task 3.2 of the ReCreate project, which explores smart logistics for the reuse of precast concrete elements reclaimed from existing buildings not originally designed for disassembly. Effective logistics and traceability are crucial enablers of circular construction, supporting quality management and the reuse of reclaimed building components. The deliverable associated outlines the logistical workflows tested in four pilot projects in each country cluster (Finland, Sweden, the Netherlands, and Germany), spanning from deconstruction to storage, refurbishment, and reuse on new construction sites. The logistical arrangements depended on which actors perform certain tasks, and at which step in the reuse process.

A core component of this task was the application of data carriers, such as QR (QuickResponse) codes, Radio frequency identification (RFID) or Near Field communication (NFC, a subset of RFID), and any other technology and practical approach, to identify and track individual precast elements throughout the process. The deliverable reviews these technologies, their integration with Building Information Modelling (BIM), and the establishment of digital identification and linking between physical components and their digital counterparts in BIM and/or databases. Another relevant feature of this process is the gathering of relevant information from the quality assurance process and the refurbishment of the elements. Key logistics aspects are discussed, such as workflows for embedding QR/RFID data into BIM models, data flow using APIs and Common Data Environments (CDE), identification of elements according to precast concrete taxonomy.

The pilots provide insights into practical challenges, decisions around actor responsibilities, and how product data quality evolves over time. Lessons learned inform more efficient and scalable logistics models that support concrete reuse, with broader applicability to other materials and construction contexts. This deliverable contributes to the systemic integration of smart logistics in circular building practices.

Due to urbanization and growing density in cities in the past century, metrics were introduced to assess daylight performance such as minimum sunlight hours and the daylight factor. The paper initially explores the shortcomings of early-stage daylight and sunlight evaluation methods. A novel methodology called Sunlight Autonomy (SA) is proposed for evaluating sunlight performance in buildings. The SA is based on the “Exposure to sunlight” criteria in EN 170307 “Daylight in Buildings,” where a computational method is used for the evaluation on a specified day. The SA concept expands the analysis temporally over the entire year, and spatially on building facades, leading to new metrics for a point of evaluation, and spatial metrics for buildings. The SA methodology is analyzed in a case study across four European cities. The SA metrics on facades between February 1st and March 21st, days in EN 17037, led to differences up to 63%. This revealed a significant shortcoming in EN 17037, relevant for Nordic regions. The differences of spatial metrics between March 21st and 50% of the year were within 5%, and up to 33% between February 1st and 75% of the year. The timestep affects the metrics and a window evaluation showed that the error of a 10-minute analysis was within 5% of daily insolation and 5 days for the annual SA. The potential of these metrics for urban planning and the architectural design process is examined. The interaction between SA and EN 17037, as well as other ongoing research developments, is discussed.

Concrete is the most used construction material, accounting for 8% of global CO₂ emissions. Various strategies aim to reduce concrete's embodied carbon, such as using supplementary cementitious materials, utilizing cleaner energy, and carbonation. However, a large potential lies in reusing concrete for new buildings in a Circular Economy, thereby closing material loops and avoiding CO₂ emissions.

This study focuses on the reuse of precast concrete elements. We present a digital workflow for assessing reuse by predicting the remaining service life, estimating CO₂ uptake by natural carbonation, and calculating the embodied carbon savings of concrete reuse. Both carbonation rates from EN 16757 and our investigation were applied to a case study building.

While EN 16757 rates suggest that most precast elements have reached the end of their service life, our assessment shows that these elements have a sufficient lifespan for reuse. Plaster and coverings significantly delay carbonation and extend service life. During the first service life following EN 16757, carbonation was 19,2 kg CO₂/m³, whereas our prediction was 5,4 kg CO₂/m³. Moreover, CO₂ uptake during service life, including reuse, was less than 6% of the embodied carbon. The climate benefits of reuse greatly exceeded those of carbonation.

Furthermore, carbonation did not have a decisive influence when applying Cut-Off, Distributed, and End-of-Life allocations for assessing embodied carbon of re-used elements in subsequent life cycles. The digital workflow is useful in quickly assessing lifespan, carbonation, and embodied carbon of concrete. It can be leveraged as a decision-making tool when designing for reuse.

Several assessment methodologies have been proposed to measure the environmental impact of buildings. However, these methodologies require processing data which is often not available or requires a high integration effort. In this paper, we propose an ontology to describe the use and reuse of prefabricated components in buildings. This ontology describes the relation between the physical object, the building component, with the digital object that represents the element in the building information model. We show that this ontology can be used to answer questions like which building components have been reused and which activities were involved in the life cycle of a building. 

Concrete production contributes to around 8-9% of global CO₂ emissions. Reusing building components in a circular economy can contribute to closing material loops and lowering CO₂ emissions. When reusing concrete elements, it is necessary to have effective methods for evaluating their reuse potential. In this study, a novel digital workflow is developed to support the reuse of precast concrete elements by evaluating their lifespan based on carbonation depth. The workflow relies on automated retrieval of material quantities and information from a digital model. This model is then coupled with environmental data on construction products and calculation methods for CO₂ uptake in concrete by carbonation. The remaining service life of concrete elements was calculated for a case study. For reference, CO₂ uptake during the first service life was estimated at 4973 kg CO₂ or 4% of the embodied carbon. Hence, the potential benefits of reuse outweigh those of carbonation. The presented approach supports the decision-making process when evaluating the reuse potential for concrete elements. The digital workflow can help designers make quick decisions concerning the lifespan and carbon footprint of concrete. The digital tool can be extended in future work with more parameters to evaluate additional sustainability indicators.

3D Concrete Printing (3DCP) represents a paradigm shift in the methods for concrete construction, offering labour automation, reduced material usage and waste, and extended design flexibility. 3DCP also enforces an inherent digitalisation, facilitating interaction among various stakeholders. This requires integrating the printed elements into the digitalised workflows that support the logistics of the process. This research project examines the potential of incorporating Near Field Communication (NFC) tags into 3DCP elements to facilitate their integration into digital workflows. NFC is a subset of RFID technology designed for short-range (< 100 mm) secure data exchange.