Blocking refers to horizontal (or vertical) wood or metal material which runs within wall or ceiling framing for the purpose of providing an attachment support point for mounted construction features like shelves, frames, cabinets and other fixed hardware. Most commoly 2×4, 2×6, or 2×8 boards are cut to size and fastened in between the framing, but light gauge metal studs can be cut to length and utilized also. Blocking is commonly installed flush with the plane of the wall on the side where hardware will be fastened.