A portable rasping platform for rasping a top surface of a wall panel includes a plurality of adjustable leveling supports, a pair of support rails, and a drum rasp assembly. The drum rasp assembly includes a drum rasp, a motor coupled to the drum rasp and configured to rotate the drum rasp at a suitable speed, and a truss frame supporting the drum rasp and configured to roll along the pair of support rails. The pair of support rails are configured to be positioned on the plurality of adjustable leveling supports arranged in parallel a certain space apart, and the plurality of adjustable leveling supports are configured to support the wall panel. The drum rasp is configured to pass over and treat the top surface of the wall panel as the drum rasp assembly is displaced along the pair of support rails.