How to Do an Exterior Corner With a Vinyl Baseboard

Place a length of vinyl baseboard at the wall in the position where it will be installed. Make a vertical pencil line along the backside of the baseboard at the point where it sticks out past the outside corner of the wall. Note that the pencil line will indicate where the baseboard must be bent around the corner. Remove the baseboard from the wall.

Fold the baseboard at the pencil line 180 degrees against itself so that the outside surface of the material is facing inward and the backside of the material is facing outward. Hold the folded baseboard with one hand so that the pencil line is facing upward.

Shave a thin layer from the backside of the baseboard with a utility knife along the pencil line. Note that the shaved portion should be 1/4 inch wide -- 1/8 inch on either side of the line. Note that this reduces the thickness of the baseboard where it will be formed around the corner. Do not cut at a depth more than 20 percent of the thickness of the baseboard or the material will become too thin.

Measure up 1/2 inch from the bottom of the flared-out portion of the baseboard along the shaved area and make a pencil mark. Shave an additional 1/8 inch wide section of the baseboard on either side of the existing cut from the bottom 1/2 inch of the baseboard to allow the flared-out bottom part of the baseboard to form more easily around the corner.

Use a hairdryer or a heat gun to heat the baseboard along the shaved areas to make folding it around the outside corner easier.

Unfold the baseboard and fold it the opposite way so the the backside surfaces of the material are touching each other and the outside surfaces are facing outward. Place the baseboard on a firm, flat surface and press the fold with a hand roller. Pull up on the flared-out edge of the baseboard and turn it inside out.

Unfold the baseboard and apply adhesive to the backside. Position the baseboard into place, ensuring the that fold is perfectly aligned with the outside corner. Press the baseboard into the place. Note the that the flared-out portion should drop down and settle into position.

Place a damp cloth over the baseboard to cool the heated areas. Remove the cloth once it is cool and wipe the baseboard dry.