A wall mounting system includes an interlocking mesh backing element mounting to a substrate, such as foam insulation. The backing element has pointed corner portions that are pushed into the substrate and retain the backing element. A wall covering layer such as drywall overlays the substrate and the mesh backing element. A fixture having has bolts, screws or other attachment members extending through the wall covering layer and the mesh backing element. The system has several backing element styles, including planar elements, inner right angle elements and outer right angle elements.