Understanding the complexity of materials procurement in construction projects to build a conceptual framework influencing supply chain management of MSMEs

Purchasing is a fundamental step of materials procurement in the construction sector, and since materials can represent up to 70% of the project's construction costs, reducing wastage and improving productivity can have big benefits, both for the environment and the economy, especially for Micro, Small and Medium-sized Enterprises (MSMEs). This manuscript will focus on the process of purchasing materials from these companies' perspective, seeking to investigate the impact of effective materials management on site. In light of the acknowledged absence of system thinking for MSMEs, this research aims to build a new conceptual framework that illustrates the complexity of the materials purchasing process in construction and embodies the risks linked to materials, relationships, information and cash flows. The conceptual framework aims to influence supply management in construction and is based on the recognition of five main levels, going from the specification of materials to data management and feedback. It is designed to illustrate the sequence, logical structure and complexities of the purchasing process. Data from the literature, followed by on-site observations, feeds into the framework.