How to Install Baseboard on Masonry, Stud and Plaster-and-Lath Walls
Learn how to install baseboard molding on every type of wall.
If a short run of molding is damaged, replace it all; for longer runs replace only the damaged area with a patch. Take a sample of your baseboard to a lumber yard to match it.
To replace a damaged section of baseboard, pry the damaged section away from the wall. Place wooden shims between the molding and wall, on each side of the damaged area.
Draw pencil guide lines vertically down the baseboard on each side of the damaged area, marking the section that will be cut away.
Using a miter box, carefully cut down each guide line, using short, accurate strokes. Cut at the angles shown below.
Remove the blocks from behind the baseboard and reattach the existing molding to the wall.
Measure and cut a new section for the gap. Apply wood glue to its mitered ends and adhesive across the back.
Position the board, allowing the glue and adhesive to adhere to the baseboard and wall. Drive in nails to strengthen the joints.
Baseboard molding can sometimes crack open and become unsightly. In most cases, this is because the joint was not properly glued and secured in place when it was installed.
Drill pilot holes through the top and bottom of the joint, making sure that you drill into both mitered edges of the corner (image 1). Apply some wood glue to the joint, and wipe away any excess (image 2). Use finish nails through the pilot holes to secure the miter in position or, for larger baseboards or moldings, use thin-gauge screws (image 3).