The widespread adoption of the European design code for timber structures (EC5) will facilitate a number of design options previously unsupported by British Standards. This code uses design equations that need characteristic material data, which exists for solid timber and some sheet materials, but not for the structural timber composites that were evaluated in this research. In this programme high-tensile steel black bolts have been used with solid timber, glulam and two commercially available structural timber composites - Microlam(TM) and Parallam(TM). The results suggest that the timber composites offer similar performance to high-density timbers in line with EC5 design guidance. (C) 2000 Elsevier Science Ltd. All rights reserved.