How to Install Baseboards (Step by Step)

Pick the back wall opposite the door as your starting point so the visible joints face away from anyone walking in. Once you know where to start, find the first stud near the corner. Josh uses the tap test - knock the hammer along the wall and listen for the solid sound. Confirm the stud center by tapping a small finish nail into the wall at baseboard height where the trim will cover the hole. Watch at 1:15. Pencil-mark the stud center on the wall so you know where to nail.

Baseboard usually comes in 12-foot lengths, so if your wall is longer you'll need to plan for a splice on a stud. Measure from the back corner along the wall to a stud center about 12 feet out and mark the top of the board there. Set the baseboard upright on the miter saw with the back against the fence. Leave the bevel at zero and swing the miter to 45 degrees. Watch at 4:10. Cut on the waste side of your mark so the joint lands cleanly on the stud.

When your wall runs longer than 12 feet, splice two pieces with a scarf joint instead of a butt joint. Butt joints crack open as the wood moves with humidity. A scarf joint hides the seam. Cut the end of the first piece at 45 degrees, then cut the start of the second piece at 45 degrees the opposite way so the second piece overlaps the first. Watch at 7:40. Land the overlap on a stud, slide the pieces tight, and shoot one nail through both layers into the framing.

Inside corners look terrible mitered because the framing is rarely a true 90 degrees. A coped joint hides any gap. Cut a 45 on the end of the second piece so the profile shows on the face. Then take a coping saw and follow that exposed profile, angling the blade back away from the face so the very edge touches first. Watch at 10:00. Sand the cope with a fine sanding sponge to clean up the edge. The coped end slides right over the square piece on the next wall.

Outside corners get a mitered joint because both faces are visible. Hold a long piece past the corner and pencil-mark on the back where the wall ends. Set the saw to about 46 degrees instead of a clean 45. The extra degree pulls the front faces tight at the show side and pushes any gap to the back where caulk can hide it. Watch at 13:20. Cut both pieces the same way in opposite directions, dry-fit, then nail them together at the tip of the corner before fastening to the wall.

Use a finish nailer or brad nailer loaded with 2-inch nails. Longer nails risk hitting electrical wire inside the wall. Drive one nail near the top and one near the bottom of the baseboard at every stud. Most studs sit 16 inches on center, so transfer that spacing from the wall to the board with a pencil. Watch at 6:00. If you've got a gap along the floor, press the trim down with your free hand as you fire the nail. The bow pulls flat as the nail sets.

Cut the tip of the paintable caulk tube small, then crimp it with needle-nose pliers so only a tiny bead comes out. Run a light bead along the top seam where the baseboard meets the wall and smooth it with a damp finger. Watch at 17:20. Fill the nail holes with lightweight spackling instead of caulk because caulk shrinks and the holes will reappear. Smear, wipe flat with a putty knife, let it dry, then brush a touch of trim paint over each spot.