SmartSide® Panel Siding may be applied over sheathed walls or, where building codes permit, directly to wall studs that have adequate corner bracing, and are spaced no greater than 16 in. on center. A house wrap or weather-resistant barrier is required for installation. SmartSide® Panel Siding cuts like regular wood with no special tools required, and is free from knots, voids, and other defects found in natural wood, and resists twisting, warping, cupping, and shrinking.