This research covers this gap by studying the failure mode of fixings in shear, when attached to different types of plasterboard with various properties. Also, the stiffening effect of the fixings is examined using different fixing diameters and the contribution of the head of the fixing is studied. The effect of composite action of light steel wall panels boarded with different types of plasterboard has also taken into account for out-of-plane loading simulating the wind pressure. A series of bending tests on 3.6 and 4.8m long walls using C sections to determine the composite action with boards was performed and was correlated with composite action theory.