Measure the length of the wall you want to install baseboard on (ignore the air vent for now). Add one-eighth of an inch to your measurment.
Cut a piece of baseboard to the length you determined in Step 1 (including the eighth of an inch).
Place the baseboard in the right area. It’s an eighth of an inch too long, so it should bow out in the middle. Push it gently in, so it snaps snugly into place.
Mark exactly where the left and right edges of the vent are on the baseboard, using the pencil. Using the square, extend those marks straight down to the bottom edge of the baseboard.
Remove the baseboard so you can see the entire vent again. Measure the distance from the floor to the bottom edge of the vent. If you’re not sure about the measurement, overestimate the distance, don’t underestimate it. You can always cut a little more off, but if you cut too much, you’ll have to start over.
Measure the same distance you found in the previous step from the bottom of the baseboard. For example, maybe the vent is 3 inches above the floor, so you would measure 3 inches from the bottom of the baseboard going up one of the vertical lines you made before. Using the square, draw a line that connects the two vertical line. You should have a rectangular section of baseboard marked off by pencil that you can cut out to make room for the vent.
Cut the rectangular section you created out of the baseboard using a router and straightedge. If you don’t have a router, a coping saw will work also.
Replace the newly cut baseboard, and snap it into place as you did previously. This time, the section you cut out should perfectly expose the air vent.
Things You Will Need
- Router with straight edge or coping saw
- An attractive option is to make the rectangle about an eighth to a quarter of an inch too wide, and leave the rounded corners from the router in place so a small portion of the wall paint is still visible around the vent cover.