Experimental Investigation for the Quantitative Assessment of Ungraded Timber in Floor Trusses

Abstract

Using timber in construction is a pivotal strategy for decarbonising the building industry. While timber is a renewable resource, particular attention must be directed towards optimising material efficiency. In regions such as the UK, where the forest area is low and the timber market heavily relies on imports, the supply chain is elongated, incurring additional financial costs, extra timing for procurement, and embodied carbon impacts through transportation. This study concentrates on the potential of English homegrown timber, relegated to short-term applications, to identify sustainable and material-efficient construction products within a short supply chain. The research introduces an experimental methodology to test structural applications of underutilised ungraded timber, working with small section boards to assess the performance and feasibility of floor trusses. Two alternative connection systems are proposed for the trusses: the conventional steel punch plate and the robotically manufactured finger joint. Truss samples are evaluated structurally and environmentally and comparatively benchmarked against proprietary industry standard steel web floor trusses. This analytical study sheds light on the viability of ungraded and underutilised timber for applications in construction, offering insights into potential value-added resources for the local construction and timber processing industries.