Skirting is another word for baseboard, which is the moulding that skirts the room and covers the space between the flooring and the wall. Installing skirting is fairly simple if the walls and corners are straight. Most homes have rooms that are divided by walls that form 90-degree angles. The skirting boards tuck into the corners at a 45-degree angle in order to match the wall corners. Cutting the boards takes some experimentation and practice.
Measure the longest wall in the room from corner to corner. Jot down the measurement on paper. These measurements are sometimes in odd amounts, so be sure to take down the measurement precisely. If you are off even 1/8-inch, you will end up with gaps at the corners.
Place a true-angle protractor on one inside corner. A true-angle protractor looks like two rulers connected at one end. Each straight edge is pressed to fit one wall at a corner. The protractor displays what the true angle of the corner is. Divide this number in half, and use the figure to set the mitre saw.
Position the baseboard upright against the saw fence. Slide the baseboard to line up with the blade at the pencil mark on the baseboard. Press the baseboard up against the fence with one hand, keeping your hand well away from the blade area. Cut the skirting using a mitre saw 2 to 3 inches from the end of the board, using the angle determined by the protractor. The sharp end of the cut should be at the back of the moulding for an inside cut. A mitre saw is designed to cut angles in moulding. The head of the saw rotates, and there are settings which allow you to set the head at the degree of cut that you want.
Measure from the sharp end with your wall length measurement. Use the protractor again to determine the true angle of the second corner. Divide, and set your mitre saw. Check your measurements and the angle. Cut the second mitre cut. The protractor measurement should be close to 45 within 1 or 2 degrees.
Fit your skirting board to the wall. Each sharp end should be toward the back for a cut from inside corner to inside corner. If you have a doorway on the wall, then you will have one mitred cut and one 90-degree cut at the doorway trim. Nail the skirting board with a finish nail every 12-inches. If you wall is very wavy, add a bead of construction adhesive to the back of the board to help it conform to the wall.
Measure, cut and fit your adjacent wall. The two mitred cuts at the corner should fit together snugly when you have used the protractor. After fitting the skirting to the wall and nailing it in place, fill your nail holes with wood fill using a 1-inch putty knife. Apply a bead of paintable white caulk along the top edge of the trim and at any corners or seams using a caulk gun.
Check your measurements at least twice. Once the moulding is cut you are stuck with the length. Be careful with the small measurement amounts to get your cuts as close as possible to what you need. Keep your hair tied back around spinning saw blades. Wear safety goggles to protect your eyes from flying debris, and keep your hands away from the saw blade.