Rethinking resources: Structural floor trusses from underutilised English timber

Abstract

This study explores pathways for integrating homegrown English timber into the UK construction sector, focusing on the structural and environmental performance of ungraded and lower-grade timber in floor trusses. Current reliance on imported timber for construction presents a missed opportunity to utilise local resources, much of which is relegated to short-term applications or bioenergy. Through an experimental benchmarking approach, we manufacture and test three alternative truss models 3m long —Finger-Jointed (FJ), Punch-Plate (PP), and Hybrid (HY)—using a mix of homegrown hardwoods and softwoods (Beech, Larch, and Corsican Pine) in both graded and ungraded forms. Structural analysis through bending tests shows that 11 out of 15 truss configurations meet or exceed the performance of the industry benchmark. The FJ and PP trusses achieve respectively ultimate loads of up to 27.5–32.2 kN—about double the benchmark load—while eliminating or significantly reducing the use of steel connectors. Life Cycle Assessment (LCA) reveals that these designs deliver up to 80 % reductions in embodied carbon. Analytical scenarios project that if homegrown timber were used for floor trusses in 100,000 new UK homes annually, the demand for timber would range from 17,750 m3 to 87,000 m3, representing 2–11 % of England's current softwood production. This research provides a proof-of-concept for industry adoption, offering pathways to reduce import dependency, promote local forestry, and support the UK in achieving its net-zero targets.