Wall systems and methods for making such wall systems are disclosed herein. According to one embodiment, a wall system comprises a plurality of vertically displaced horizontal support members, and a wall panel having at least one inwardly-extending ridge. The wall system also includes at least two foam insulation blocks. Each block has a surface that is adapted to conform to the shape of the inwardly-extending ridge of the wall panel. The blocks are spaced apart along each of the horizontal support members and are fastened between the panel and the support member. The spacing created by the blocks allows for a blanket of insulation between the blocks and the support members to expand, improving the system's insulative properties.