A building array (800, 900, 902) comprising at least one building element (100, 200) having a first face (102, 202), a second face (104, 204) and a peripheral edge member (108, 208), the first face and second face being spaced apart to define an intermediate portion (106, 108), the peripheral edge member extending around the intermediate portion whereby at least a portion of the peripheral edge member comprises an edge profile (112, 212); and at least one boundary element (300, 400, 500, 600) comprising a planar base member (304, 404, 504, 604) removably attachable to a structural support element (802), at least one flange (306, 406, 506, 606) extending substantially orthogonally from the planar base member and an edge restraining formation (310, 410, 510, 610) extending laterally from the flange remote from the planar base member. The edge restraining formation is configured for releasably engaging with the edge profile of the building element. The at least one building element and the at least one boundary element are arrangeable together in series on a structural support element to form the building array.