Abstract: A two part, weight bearing shim adjustable in height. The shim comprises two generally triangular or wedge shaped members. A base member has a flat bottom surface and a stepped upper surface. A smaller member is placed in inverted relationship on the base member. The smaller member has a stepped lower surface cooperating with the stepped upper surface of the base member. The upper surface of the smaller member is parallel to the bottom surface of the base member after assembly. The base and smaller members are mutually keyed to prevent improper interfit during assembly. The base member has vertical voids or bores formed in its body. This construction promotes ability of the bottom surface to engage a rough or irregular environmental surface, and minimizes the amount of constituent material required for fabrication. Recycled plastic is a preferred constituent material.