A shimming device for attaching a substrate to a stud wall includes a plate, which has a first edge that is linear. The plate can be mounted to a respective opposed side of one of a plurality of studs to which the substrate is to be mounted. The plate is one of a plurality of plates that can be positioned on and mounted to the plurality of studs so that each plate is positioned at a respective support point for the substrate. Each plate is positioned with the first edge of the plate proud of an edge face of the stud and so that the first edges of the plurality of plates define a plane. The substrate, upon mounting to the plurality of studs, is parallel to the plane.