This is the technique we use to install bracing for a ceiling fan or a light fixture in the center of a vaulted ceiling. Usually, it is constructed out of 2" x 6" material with a 6" square to mount the ceiling fan or light fixture to. When a wider canopy is required, we make the block out of wider wood in the same fashion. A shallow pan box is used as the box and is the appropriate size for the sheetrock or wood that will be the finished surface.