Run a stud finder along the ceiling to locate and mark the ceiling joists. Determine the locations and even spacing of the wood-look beams based on the joist locations.
Measure the interior width of a beam. For each beam location, run two lengths of painters tape outside the stud at a distance equal to the beam width. The tape is a guide for beam placements.
Cut several blocks out of 2-inch by 4-inch boards to fit the interior width of the beams.
Place the blocks between the lines of painter’s tape, and screw them to the ceiling joists. Start blocks 2 feet from the walls, and place them every 4 to 6 feet in between.
Remove the painter’s tape.
Cut the beams to the length of the room using a circular saw.
Extrude beads of poly construction adhesive along the top edges of the beams, where they will sit against the ceiling.
Fit each beam over each row of wooden blocks. Drive screws through the tops of the sides of the beams and into the wooden blocks. Countersink the screws slightly.
Cover the screw heads with matching wood putty.