Abstract: A joint for use in a partition wall building assembly and method in which abutting edge surfaces forming the joint are provided with rigid self supporting fibres projecting substantially normally from the surfaces and intermeshed to resist shear movement between the surfaces. The top and bottom surfaces of a partition wall panel are provided with the projecting fibres which intermesh with fibres on the ceiling and floor surfaces to hold the panel in position. The ceiling and floor surfaces are relatively movable vertically to clamp the panel and ensure complete intermeshing of the fibres. The length and density of the fibres is such that shear movement is substantially prevented.