With the trend towards sustainable building design, timber-concrete composite floor systems attract great interest among building designers and developers as an alternative to the profiled steel-concrete deck that are commonly used in commercial construction. The proposed 2-layer composite floor deck consists of a profiled nail laminated timber (NLT) mainly designed in tension and concrete slab in compression. A numerical modelling approach was developed via commercial software ABAQUS to simulate the composite action of wood-concrete floors under four-point bending. The effects of NLT profile, thickness of concrete slab topping, fastening details, and shear span on composite action were analysed through a comparison of stress-strain development in both concrete and timber layers and the loaddeformation responses in shear connections of composite floors. Initial construction details of this composite floor system were therefore defined based on the preliminary analysis and will be examined further in the experimental phase of the project.