Beams support roof or floor structures. The beams are usually 8 inches wide so that holes for plumbing and electrical lines can be cut or drilled through the beams without destroying the structural integrity of the beam. Heavier load bearers, or beams that have several holes, must be thicker than 2 inches to provide the strength needed for the building. Thicker beams can give the added support. Additionally, bolting boards together allows the builder to make a beam longer than the standard 12-foot length of the lumber.
Measure 4 feet along one 2-by-8-inch board. Cut the board. Repeat with a second board.
Lay a 12-foot board on the ground. Butt the end of an 8-foot board to the end of the 12-foot board.
Lay a 4-foot piece on top of the 12-foot board and line up the ends. Drill two holes through the end of both boards. Insert a carriage bolt into a washer. Lift the edge of the board and insert the bolt. Place a washer on top of the protruding end and tighten the nut with the wrench. Repeat with the other hole.
Lining up the edges carefully, drill two holes at the other end of the 4-foot board. Place carriage bolts and washers in the holes and tighten the two boards together.
Butt the end of a 12-foot board against the end of the 4-foot board. Drill holes in the end of the board and bolt it down with the carriage bolts on both sides. Finish the beam with a 4-foot piece at the end.