How to Install Baseboard Around a Door

Lay out the top edge of the baseboard molding without relying on the floor being level. Place the molding against the wall, position a long spirit level on top of the baseboard and center the bubble. Examine the bottom edge for any gaps between the molding and the floor. Mark the highest point on the wall, above the molding, where the molding rests on the floor, then set the molding to the side.

Repeat this exercise on the three remaining walls until you’ve established the highest point of the entire floor. Attach a line spirit level to a chalk line, level the line by centering the bubble, remove the level and snap a level chalk line across all four walls. Use the highest mark on the wall as your datum point. Once the baseboards are installed, any gaps between the bottom edge and the floor can be filled with matching wood filler or caulk.

Measure the length of the wall to the right of the doorway and then the wall to the left; add 1/8 inch to each measurement. Transfer the measurements to two lengths of baseboard molding. Adjust a miter saw for a 90 degree cut in both directions, and cut the side wall moldings to length.

Place the baseboards against the wall. Locate the center lines of all wall studs with an electronic stud finder, and mark the stud locations on the baseboards.

Push one end of the molding into one corner and flex the molding so that it takes up the extra 1/8 inch and fits snugly into the opposite corner. Once both ends are in place, push the center of the molding against the wall and secure it to the center stud by hammering in an 8D finish nail approximately 3/4 inch from the floor. Be sure the top of the molding lines up with the chalk line.

Secure the baseboard to the rest of the studs with one finish nail about 3/4 inch above the floor, and a second nail just below the “dado,” or groove, along the top of the molding. Repeat on the opposite side wall.

Carefully measure the distance from the edge of the door casing to the corner of the longest wall and add 1/16 inch to this measurement. For this exercise we’ll assume that this is the wall to the right of the doorway.

Transfer this measurement from the left square cut top edge, to the right of a length of baseboard molding. Adjust your miter saw to cut a 45 degree vertical angle with the blade angled toward the left. Position the right edge of the baseboard vertically against the miter saw fence, with the cut mark aligned with the left edge of the inward facing saw blade, and cut the baseboard to length. This cut will expose the profile on the right end of the baseboard.

Use the “coping” technique to butt the right-hand exposed profile on the mitered edge of the baseboard against the upper dado profile on the square cut baseboard on the right-hand wall as follows: Follow the profile by cutting along the edge at a 90 degree angle to the face of the baseboard molding with a coping saw. This will duplicate the profile so that it fits neatly against the face of the adjoining molding in the corner.

Spring the baseboard into position as described in Step 5 and secure the molding with two finish nails hammered into each stud along the wall. Keep the top of the baseboard lined up with the horizontal chalk line across the wall to ensure a proper fit between the corner coping and the adjoining molding profile.

Repeat these steps by adjusting the miter saw to a 45 degree angle in the opposite direction to cut the left-hand bevel, then coping and attaching the second length of baseboard between the door casing and the left-hand corner as described. Next, cope and install the baseboard across the opposite wall the same way.

Set all nail heads below the surface of the baseboards with a nail set and hammer. Fill the nail holes with a matching wood filler and take up any remaining gaps between the bottom edges of the baseboard and the floor with matching wood filler or, if you intend painting the baseboards, with silicone caulk.

Fill the slight gap between the rounded edge of the door casing and the front edge of the baseboard with wood filler or silicone caulk, if necessary.