Choose a corner at which to begin. Hold a pre-made molding corner in place on the wall in the exact location at which you will fasten it. Run your pencil along the sides of the corner, marking on the wall where the corner will meet with the base molding. Repeat this process at the next corner down the line.
Attach the first corner to the wall. Return to the first marked corner, and attach the pre-made corner. Ensure that you are placing the corner on the mark that you previously made. Position the nail gun so that the fastener will penetrate one of the wall's framing members.
Take measurements for the length of the base molding. Use the installed molding corner as a frame of reference; butt the tip of the tape measure against the installed molding corner, extend the tape measure to the mark you made at the opposite end of the wall and note the length between these two points. This measurement is the length of the piece of base molding that will fit between the two corners.
Mark the molding for cutting. Refer to the measurement taken in the previous step. Attach your measuring tape to one end of a length of base molding, extend past the required measurement and make a "V"-shaped mark on the edge of the molding at the correct spot.
Cut the base molding. Place the base molding on the chop saw and, before activating the device, lower the blade, check where it lands and adjust the position of the molding. Pull the saw's trigger, steadily lower the blade and cut the molding at your mark.
"Dry-fit" the base molding and remaining corner. Hold the corner on your mark and place the molding between the two corners. If the molding is too short, measure and cut again. If the molding is too long, trim until you achieve a snug fit.
Put in the second corner. Place the corner on your mark, and fasten using the nail gun.
Install the length of base molding. Place the molding between the corners, and attach using the nail gun.
Things You Will Need
- Tape measure
- Carpenter's pencil
- Chop saw
- Finish nail gun
- Molding corners, both inside and outside (as required)
- Professional carpenters often install base molding 1/16 to 1/8 inch above floor level to prevent damage from the potential movement of the structure.
- Many manufacturers and retailers refer to pre-made corners as "moulding blocks."