Abstract: A pod comprises a box-section steel frame (1) having horizontal structural members (4, 11). A floor is provided by welding a 6 mm steel plate (10) to the horizontal structural members (4, 11). The plate (10) has a checkered pattern of 2 mm ridges on its lower surface. A combination of inherent stiffness of the plate material, the ridges (50) and welding to both edge (4) and internal (11) structural members achieves sufficient stiffness of the floor to allow it to be tiled off-site during manufacture because the floor is thin, there is no need for the builder to provide a recess in the concrete on-site.