I-beams in buildings are for structural support and sometimes need to be enclosed to hide it from sight, such as when refinishing basements. The best way is to build a soffit that will hide the beam without having to drill into it. Although time-consuming, this is a job that can be done by anyone with basic carpentry or woodworking skills.
Measure the length and height of the I-beam needing to be covered. Allow an extra 2 inches below the bottom of the beam.
Cut lengths of 2-by-2 lumber with the circular saw to make two lengths to fit from wall to wall in the room. Take the height measurement and subtract 4 inches off it. Cut two pieces of 2-by-2 to that length and place in between the long runs of 2-by-2 at the ends.
Screw the outside pieces to the inside pieces with the wall screws tightening them fully with the screwdriver.
Measure and cut more pieces to fit inside the long sections. Space the pieces with 16-inch centres and screw them in place. The finished piece will look like a ladder.
Screw the frame to the floor joists beside the I-beam. Then level it so that it is vertical to the floor and screw it to the walls at each end of the frame.
Make another identical frame to fit the opposite side of the I-beam and screw that in place.
Measure and cut 2-by-2 pieces to fit into the underside of the I-beam between the two outside frames. Space them with 16-inch centres and screw into place.
Cut the plywood to size and nail into place with the hammer on the frames one side at a time. This will enclose the I-beam.
Leave a little space between the I-beam and wood to allow for expansion and contraction of materials.