The purpose of this study was to determine the behaviour of biaxially loaded, 4-ply, spliced, nail laminated timber assemblies, under simply supported and fixed end support conditions. The study builds upon American work and utilizes the modern Canadian In-Grade Testing approach. The study tested 33 commercially manufactured S-P-F Results indicate that the support conditions had a very significant effect on post bending performance and that axial loading in this range had no effect. There was joint motion detected in all cases of the fixed end support condition by the design deflection limit. Conventional structural theory was used to develop simple mo ifiers for predicting similar post performance under both support conditions. This study concludes, that current design values based on simply supported test conditions may be overly conservative, and that they do not fairly represent the capacity of a post in its probable end-use conditions.