Make each bed leg from two 48-inch 2-by-6 boards. Hold the boards together at a 90 degree angle with C clamps. Use the power drill to screw them together with 3-inch wood screws, about 10 per leg.
Measure from the bottom of each leg and make a heavy pencil line – on both angles of the leg -- at 12 inches and 24 inches. These marks locate the top of the cross-support boards.
Attach both sets of new legs to the daybed frame so they cover up and “replace” the daybed’s legs. You’ll need helpers to hold the bed up while you do this. Drill two 3/8-inch offset holes through both sides of the new legs and into solid day-bed wood above the old legs. Insert and then finger-tighten a bolt, both washers and a nut at each hole.
Bolt the two cross-support boards to the two new legs attached at each end, using two offset 3/8-inch holes at each attachment point. Set the cross pieces inside the assembled legs. Locate the top of the first cross-support at the 12-inch mark and the top of the second at the 24-inch mark.
Attach the two lengthwise cross-supports -- or stretchers -- in the same way, on what will be the loft bed’s “wall side.” This configuration allows below-bed space to be used as a play or study area. The tops of these boards also reach the 12-inch and 24-inch leg marks.
Tighten down all the nuts so the bolt heads bite into the wood. Apply two coats of paint and let the loft bed fully dry.