1. Introduction
The construction sector is considered not only as a major consumer of virgin materials [
1], but also a major contributor to waste generation [
2]. In the European Union (EU), it constitutes more than a third of all waste generated [
3]. In the province of Québec (Canada), where this study is conducted, the construction industry (the province’s fourth-largest economic sector) generates, through construction, renovation, and demolition (CRD), over 3.5M tonnes of highly heterogeneous residual materials for which there are few options for recovery [
4]. This leads to huge amounts of landfilled materials and an increase in the use of virgin resources. Therefore, it is essential to rethink current waste management practices, for example by applying circular economy (CE) principles to building demolition such as deconstruction concept, also referred to as disassembly or selective demolition [
5]. In regards to the United Nations’ sustainable development goals (SDGs), reducing waste generation through prevention, reduction, recycling, and reuse, and using more efficiently natural resources are among the key targets of SDG 12; “Ensure sustainable consumption and production patterns” [
6]. Considered as a more-resource-friendly alternative compared to standard demolition [
5], deconstruction involves dismantling a building with the aim of maintaining the highest possible value for its materials and maximize their recovery potential [
7,
8] (Chini and Bruening, 2003; Marzouk and Elmaraghy, 2021). This results in reducing the use of raw materials, diverting as much of the materials as possible from landfill and reducing site impacts (dust, soil compaction and loss of vegetation), air pollution and energy consumption [
9] (Guy and Gibeau, 2003). Deconstruction also stimulates innovation and the local economy while preserving local heritage such as valuable and historic materials [
10]. However, shifting from demolition to deconstruction practice requires thorough changes [
11].
This study aims to guide the CRD sector towards deconstruction to maximize the reuse of materials in CE and sustainability perspectives. It focuses on a case study in the Gaspésie region (central eastern Québec) in Canada; it presents five buildings on two different sites (in the towns of Grande-Rivière and Chandler) to be completely deconstructed and a site to which the deconstructed materials can be sent for reuse (École de permaculture in the town of Percé). A first in the region, this project is led by the general manager (GM) of the Régie intermunicipale de traitement des matières résiduelles de la Gaspésie (the waste management agency of the Gaspésie region, referred to as RITMRG) as the client (and project Promotor-Leader). The RITMRG specializes in waste management and owns and operates a sorting centre, technical landfill site and composting site. It also operates waste drop-off centres and is responsible for processing recyclable materials and awarding waste collection and transportation contracts. The project got underway in May 2022 and was completed in October 2023. This collaboration project is one the 19 projects launched by the Circular Economy (CE) Acceleration Lab for the construction sector led by the Centre for Intersectoral Studies and Research on the Circular Economy (CERIEC)
1 of the École de technologie supérieure (ÉTS). CERIEC’s mission is to shape and contribute to the deployment of the CE through interdisciplinary scientific research and development and liaison initiatives with economic agents, governments and civil society. The CE Acceleration Lab aims to demonstrate ways to integrate and generalize CE strategies in the construction sector through innovative experimentation projects co-created with stakeholders.
The problem described by the GM of the RITMRG is that current practices in the CRD sector are not adapted to CE and sustainability principles: materials are consumed as single-use resources, leading to an increase in the consumption of new resources, the limited capacity of raw resources to meet demand, high costs to acquire (new) resources and manage residual materials throughout their life cycle (extraction, transportation, processing, distribution and end-of-life management), an increase in the ecological footprint of materials and a lack of availability of end-of-life materials for reuse, especially locally. The goal is therefore to extend the service lives of resources through reuse. The objectives are to: 1) design an efficient deconstruction process that promotes reuse and 2) develop decision-support tools for deconstruction projects (planning, development and oversight). This study focuses on the first objective and, more specifically, three main questions:
1) What are the issues and obstacles of deconstruction and, by extension, of CE in the CRD sector?
2) What solutions and best practices promote deconstruction and CE in the sector?
3) What deconstruction process should be designed to maximize the reuse of materials?
Our approach is inspired from Lean thinking and follows Action Research (AR) methodology. It specifically adopts the phases “Define”, “Measure”, “Analyze” and “Innovate” of DMAIC (a Six Sigma tool largely used in Lean projects, which refers to Define, Measure, Analyze, Innovate, and Control), and uses different Lean tools such as SIPOC (Suppliers, Inputs, Processes, Outputs, Customers), risk and stakeholder analyses, process mapping, A3 sheet, a think-tank workshop, and effort-benefit matrix, within each phase. The “Control” phase of DMAIC is excluded from our study, it could be carried out when implementing the proposed deconstruction process as part of future deconstruction projects.
Lean thinking appeared in the automotive industry (Toyota Production System). Now, it is well known and applied in various sectors including CRD [
6,
12,
13,
14]. In the construction sector, Lean application is known as “Lean construction” [
12]. In [
12] and other studies it is stated that the adoption of Lean principles in construction is challenging. It is reported in [
15] that despite the great interest to Lean thinking, Lean application to construction is sporadic and many contradictions regarding Lean “values” are observed such as excessive consumption of materials, disconnected activities, establishment of obstructed flows, focus on costs rather than value, inefficient measurement systems, high modification levels, and employee safety issues. Du
et al. (2023) [
16] add that there is a lack of a systematic framework for the promotion of Lean application in construction. Regarding Lean application to deconstruction projects, there are only a few works published in the literature. On the other hand, despite increasing efforts to introduce and promote deconstruction practices, there is a lack of studies exploring this concept, involving real case studies in particular, and proposing a comprehensive deconstruction process that may be implemented in the real-world. This research helps fill these gaps. It contributes to the body of knowledge in Lean construction and deconstruction in both practice and the theory. It presents in detail all phases of the project and provides a description of the Lean tools used as well as the results obtained at each phase. This study provides a framework for researchers and practitioners in the CRD sector, interested in implementing Lean thinking to address important problems such as waste management and material reuse in deconstruction projects.
The remainder of this paper is organized as follows:
Section 2 presents a literature review to identify the major issues and obstacles in deconstruction and CE in construction as well as solutions and recommendations to move towards effective deconstruction. It also presents recent works reporting on Lean construction and “Lean deconstruction”.
Section 3 presents our methodology, Lean implementation phases (following DMAIC), and the results at each phase. Finally,
Section 4 discusses the results and presents our conclusions and research perspectives.
4. Discussion and conclusions
Deconstruction is considered a more viable alternative to traditional demolition from the technical, financial, social, and environmental perspectives. This study aims to guide the CRD (Construction, Renovation, and Demolition) sector in improving deconstruction practices by using Lean principles and AR (Action Research) methodology. The AR methodology proved very efficient in this project. Indeed, the study was conducted in close collaborated with the General Manager (GM) of the waste management agency of the Gaspésie region – RITMRG (Québec, Canada), where two deconstruction projects focusing on maximizing the reuse of materials were carried out for the first time. This collaboration project is one the 19 projects launched by the Circular Economy (CE) Acceleration Lab for the construction sector led by the Centre for Intersectoral Studies and Research on the Circular Economy (CERIEC) of the École de technologie supérieure (ÉTS), which greatly facilitated bringing together the research and practice worlds, and provided effective mechanisms for co-creating innovative solutions based on the scientific and field knowledge to address the important problem of deconstruction and contribute to accelerate a necessary change towards circularity. The knowledge transfer strategy of the CE Acceleration lab will cover the results of this study and help disseminate them – thus fostering a change in practices through the replication and improvement of deconstruction practices.
By using Lean principles, it was possible to clearly identify and communicate to the stakeholders (i.e., members of the CE Acceleration Lab) the important phases of the study, define precisely the problem, the scope, and the project team’s progress. Mapping the deconstruction process implemented in the Gaspésie region clarified the main steps, the responsibilities of the stakeholders involved and their interrelations, and showed the complexity of the process. Furthermore, the process mapping helped identifying the issues and obstacles encountered at every step of the phases of the process (pre-deconstruction, deconstruction, pos-deconstruction) and facilitated sharing them with the stakeholders. The different meetings and workshops held during the project helped keeping the stakeholders interested and willing to contribute to address the issues identified in order to improve the deconstruction process and practices. The feedback of the different stakeholders involved was positive and the results conclusive.
In the field, it was reported by the GM of the RITMRG that the contractor and team proved their ability to adapt and to fulfill the contract, and local spin-offs were observed. According to the GM of the RITMRG, since the cost of landfilling is high, the costs associated with deconstructing of the two sites in Gaspésie region are equivalent to or lower than those generated by traditional demolition. The GM also noted a substantial reduction in the quantities of materials sent to landfill. This is very encouraging for future deconstruction projects in (and outside) the region. Still, a number of issues and obstacles arose during the planning and execution phases. The project team used three different and complementary strategies to identify relevant solutions to address those issues and improve the deconstruction process for future projects. The firs strategy was to use the solutions and best practices identified in the literature. The second consisted in collecting the recommendations of the GM of the RITMG and the contractor (and team) based on their observations and experience on site. Finally, the third strategy was based on gathering solutions and recommendations from the members of the CE Acceleration Lab, having relevant experiences and expertise in the CRD sector, but not directly involved in the Gaspésie deconstruction projects. It was interesting to observe how the diversity of the experts’ backgrounds and perspectives resulted in different, yet complementary recommendations, that ultimately helped the project team to propose an improved deconstruction process. The issues identified in the literature also merit close attention, since they may arise in other projects (e.g., long delays to complete the work, the need for a specialized workforce, insurance and warranty problems associated with the use of end-of-life materials, health and safety risks and risks associated with the transportation of materials meant for reuse). Good practices recommended in the literature include raising awareness of the CE among government agencies and the public, and educating and continuously training workers and stakeholders in the CRD sector.
This study contributes to the body of knowledge in Lean construction and deconstruction in both practice and the theory. Deconstruction practices are not sufficiently studied in the literature and Lean construction still has limitations as reported in recent studies; such as the lack of Lean understanding and the lack of a systematic framework for the promotion of Lean application in construction. This study contributes to address these gaps by providing a roadmap for implementing Lean in real-world problems in the CRD sector as well as a comprehensive deconstruction process and recommendations promoting deconstruction practices that could be implemented in the real-world. The next stage of this research work will focus on optimizing the planning of the deconstruction, storage and transportation of materials to their destination sites (recycling, landfill, reuse, etc.) by using mathematical modeling. This future research work will build on the issues and solutions related to the logistics of the materials (on and off site) identified in practice and in the literature through this study.