A panel assembly for a building structure including a support frame that is mountable relative to a building substrate, the support frame including a plurality of first members extending in a first direction and at least one member extending in a second direction and overlaying the members in the first direction, at least one sheeting member provided on at least one side of the support frame so that the support frame and the structural sheeting define a zone for a cementitious material, and a layer of cementitious material positioned against the structural sheeting to at least partially fill the zone.