If you need to maximize the amount of space in a room, you can convert a conventional boxed-frame bed into a loft bed. You can use standard 4-by-4-inch posts or you can visit your local home improvement center and purchase pillar posts designed for porch supports. Pillar posts are turned on a lathe to add a decorative touch. This eliminates the utilitarian look of plain planar lumber and will give your loft bed the look of an ornate four-poster.
Remove the mattress, box spring and slats from the wooden frame of the bed and place them to the side.
Flip the bed frame upside down so the legs face upward. Remove the bolts that secure the legs to the wooden bed framing if possible. If the legs are permanently attached, cut the legs off flush with the bed framing with a flat saw. Sand any rough edges down with a sanding block or file.
Place the bed frame on its side. Place a leg on the floor on each end of the bed frame. Position the legs on the inside of the bed frame. Slide the legs against the bottom of the railing that the box spring rests on. Drill two evenly spaced pilot holes through the end of the bed frame and into the pillar posts. Secure the posts to bed frame using ½-inch-wide lag bolts long enough to go through the frame and an inch or two into the post. Flip the bed onto its other side and attach the other two pillar posts in the same manner.
Place the bed upright on the posts.
Measure halfway up from the bottom of each post and drill a 1-inch-wide hole 1 1/4 inches into the post so that the holes on the left legs (as you're looking at the bed) face each other and the holes on the right legs face each other. Drill two holes in the back pillar posts so they face each other.
Measure the distance between the front left leg and the rear left leg. Add 2 inches to the measurement, then cut two pieces of 1-inch dowel rod to match the measurement, using a miter saw.
Measure the distance between both rear legs and add 2 inches to the measurement. Cut a piece of 1-inch dowel rod to match this measurement.
Apply glue to each hole, then press the rods into the holes. This creates the bracing needed to stiffen the legs.
Place the slats, box spring and mattress onto the bed frame.
Place a wooden ladder against the bed frame and mark the rails where the ladder meets the top of the bed. Cut off the excess part of the wooden ladder with a miter saw.
Drill a pilot hole through each ladder rail at the top of the ladder and attach the ladder to the bed frame with two ½-inch-wide lag bolts.