How to Build Beams in a Room

Run an electronic stud finder along the ceiling. When the stud finder beeps, it indicates that one edge of a joist has been located. Mark the point lightly with a pencil. Move the stud finder toward the point marked from the other direction, marking the other edge of the joist when the stud finder beeps again. Mark the midpoint between the two marks as the center of the joist with a marker.

Draw a line across the ceiling on top of the joists from wall-to-wall to clearly indicate the location of the centers of the joists, use a straightedge as a guide.

Measure from wall to wall across the ceiling at each of the marked points. Jot down the measurements.

Cut pieces of 2-foot-by-4-foot lumber with a circular saw to equal the dimensions taken in Step 3. Cut one piece of 2-by-4 and three pieces of 1-by-4 for each beam you want to make.

Pre-drill holes down the center of the 2-by-4 lumber. Drill holes at each of the ends through the faces of the 2-by-4s and then every 8 inches along their length.

Drill pilot holes down the line in the joist to match up with the pre-drilled holes on the 2-by-4s.

Position the beams in place on the ceiling. An assistant is needed to hold the other end of the beam up while the first screws are secured. Screw the 4-inch wood screws through the pilot holes on the beams and into the holes in the ceiling with a screwdriver bit on an electric drill.

Hold a 1-by-4 up along one of the the 2-inch edges of the beam, with one 1-inch edge flush against the ceiling. Screw in a 1 1/2-inch wood screw through the 1-by-4 and into the 2-inch edge of the 2-by-4 affixed to the ceiling every 12 to 16 inches down the length of the wood.

Line up the remaining two 1-by-4s in an L-shaped formation so one 1-by-4 is flat along the ground and the other is upright along its edge. Ensure that the top of the upright matches up with the open side of the 2-by-4 on the ceiling. Screw a 1 1/2-inch wood screw through the bottom of the outside face of the upright 1-by-4 into the 1-inch edge of the 1-by-4 on the ground.

Drill pilot holes every 12 to 16 inches along the top edge of the upright 1-by-4. Hold the L-shaped assembly up flush with the ceiling and the other edge of the 2-by-4 on the ceiling. Screw 1 1/2-inch wood screws into the pilot holes and through the opposite bottom edge of the box beam.

Repeat for each beam across the ceiling.