How to Install Baseboards
Baseboards hide the expansion gap and give a floor its finished edge. This guide walks through it step by step – and shows you how to read off the exact linear feet before you buy.
Work out your material first →
Baseboard is sold in fixed lengths and cut to fit, so the first thing to get right is how many linear feet to order. Draw your room in the free planner and it reads the perimeter straight off your floor plan and takes off the door openings – then follow the six steps below to install the boards.
Installing baseboards in 6 steps
Measure the perimeter and buy the lengths
Draw the room in the free planner: it gives the linear feet of baseboard as the room's perimeter minus the door openings, because no board runs across a threshold. All you add by hand is a little for the miter cuts, then buy in whole boards. Without a floor plan, run a tape around the walls and subtract the door widths yourself.
Choose the fastening
Decide how the boards will hold: a clip rail screwed to the wall that the baseboard snaps onto, construction adhesive run along the back, or nailing and screwing straight into the wall. Clips let you lift the boards later to pull cables; adhesive suits flat, solid walls; screws hold best on uneven ones.
Cut the corners
Cut 45° miters for both inside and outside corners so the profile wraps cleanly around each angle. On uneven walls an inside corner sits tighter if you cope it: cut the first board square to the wall and scribe the second to its profile so it laps neatly over the first.
Scribe to uneven walls
Few walls are dead straight, so hold each board in place and scribe its back edge to follow the bumps. Plane or sand down to the line until it sits flush along the whole length, with no gaps opening between the board and the wall.
Fasten to the wall only
Fasten every board to the wall and only the wall – never nail or screw down into the floor. The floor is laid floating and has to keep sliding under the boards; the baseboard covers the expansion gap while leaving the floor free to move, so it can't buckle.
Fill the seams and paint
Caulk the top edge and fill the miter joints and any nail holes with wood filler, then wipe smooth. Sand lightly once dry and paint the boards if the finish calls for it – do the last coat after fitting so the touch-ups blend in.
Know the linear feet before you shop
Instead of pacing the room with a tape, the free planner reads the perimeter straight off your floor plan, subtracts the door openings and gives the linear feet of baseboard to buy – only the allowance for the miters is left for you to add.
Open the free planner →Frequently asked questions
- Should I glue or screw baseboards?
- Both work; it depends on the wall. On flat, solid walls construction adhesive is quick and leaves no visible fasteners. On uneven or hollow walls, screws (or a clip rail) pull the boards in tight and hold where glue alone would gap. Whatever you choose, fasten into the wall, not through the floor.
- Miter or cope an inside corner?
- A 45° miter is faster and looks clean when the corner is truly square. But few room corners are exactly 90°, and a mitered inside joint tends to open up. Coping – cutting one board to the profile of the other – follows the real angle and stays tight even on out-of-square walls. Use miters on outside corners, coping on tricky inside ones.
- Why can't I nail baseboard through a floating floor?
- A laminate or engineered floor is laid floating: it expands and contracts and must slide freely behind an expansion gap at every wall. Nail or screw through it and you lock it in one spot, so it buckles or the joints pull apart. Fastening the baseboard to the wall alone hides the gap and keeps the floor free.