- 1). Mark an even line 32 inches from the floor all the way around the room. Take a measurement from the floor every 2 feet along the perimeter of the room and then join the marks, using a 4-foot-long level. The resulting line does not need to be perfectly level, but it does need to be parallel to the floor. Locate studs along the line with a stud finder and mark them on the wall, using marks on pieces of masking tape.
- 2). Trim the first piece of molding, using the miter saw set at 90 degrees. Place the end against a corner of the room. If the piece is not long enough to reach across the room, cut the far end with the miter saw at a 45-degree angle. If the piece will reach, trim the end to length with the miter saw set to 45 degrees. Attach the piece to the wall with the top along the line marked earlier, using 6d nails into wall studs (using the reference marks made earlier to make hitting a stud easier). Hammer the nails in so that 1/8 inch is left sticking out, then tap the nail the rest of the way in with a nail set or another nail. This will prevent the hammer from accidentally marring the wood.
- 3). Cut a scrap piece of molding at a 45 degree angle with the miter saw. Test it against the previous piece to see how it fits. The angle may need to be adjusted on the cut to give a tighter fit. Once the angle is determined, cut the end of the full molding piece and test the fit. Use the coping saw, files and sandpaper to refine the cut and give an almost invisible seam. Attach this piece to the wall just like the earlier piece. Repeat this process around the entire room.
- 4). Layer the second piece of molding on top of the first, centering it on the underlying piece. Make pencil marks along the underlying piece as a guide. Attach the top piece, using very small finishing nails that are ½ inch longer than the thickness of the wood. Again, drive the nail partway and then tap it in with a nail set or another nail. If the top piece is very thin or narrow, drill 1/16-inch pilot holes to nail through to prevent splitting. Glue can also be used to attach smaller pieces. Continue attaching the top molding, using the same techniques of cutting and fitting used for the base pieces.
- 5). Fill any gaps or seams with latex painter's caulk or with joint compound and sand it smooth if the molding will be painted. If the molding is to be stained, mix some of the stain with wood putty and use that to fill any gaps or nail holes. Mixing the stain with the putty produces a better color match.
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