9 Steps to Properly Install Baseboards

Man installing skirting board

Written by My Home Handyman

March 4, 2022

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If you are going to be drywalling, it almost always means installing baseboards as well. If you want to install baseboards like a pro, it means following a few simple steps along the way.

To properly install baseboards, you need to make sure that you measure and mark accurately. From there, it is about establishing the height of the baseboards and installing them as well as cutting and installing the joints.

Step 1: Planning is Key

As is the case with any project, planning is key. Start by measuring and cutting the baseboards for each wall. Number each board and write that number on each spot on the wall so you know where they go at the time of installation.

You should also locate the studs and mark them out. The studs will serve as the base when it comes time to nail the baseboards into place. If you have boards that meet outside corners, make sure to leave them a little longer than the wall so that you can make your mitre cuts.

Step 2: Baseboard Height and Scribe

Next is establishing the baseboard height. Use a 4-foot level to make sure the floor is even. If it isn’t, find the lowest point. Use the top of the baseboard as your benchmark, making horizontal marks every couple of feet as well. Snap a chalk line between the marks at the perimeter to show where the top edge of the baseboards will go.

Start with an inside corner and tack the first board into place. Next, hold a pencil on the baseboard and the point of it against the floor. Slide a compass along the board’s length, all while keeping the points vertically aligned.

Step 3: Nailing the Baseboards

It is time to set it in place. At each subsequent stud location, take a pair of 8D finish nails and hammer them through the baseboard. Make sure to do so at a slight downward angle, right near the bottom and top edges.

Just be careful not to mark the wood along the way. You can use a nail set to drive the heads just below the surface of the wood for a cleaner finish.

Step 4: Marking Outside Corner Joints

With the baseboards in place, it is time to work on the corners and joints. Take one end of the board and fit it snugly up against an insider corner. Move to the other end, drawing a vertical line up the back of the baseboard. Use the edge of the outside corner as the guide.

Mark the top of the board so that you can see the direction of the mitre. Then remove the marked board, placing the one that will make up the other half of the mitre up against the adjacent wall and mark the same way.

Step 5: Mitre Cut On the Outside Corner Joints

Grab your compound mitre saw and set it to 45 degrees. You will cut each mitre to the outside of the line so that the joint can be fine-tuned if need be.

When you have made the cut, place both boards against the wall so that you can look more closely at the joint. If it isn’t tight on top and the side, you can take it back to the saw or use a block plane to trim the wood until it fits tightly.

Step 6: Cutting Biscuit Slots

To ensure a tight outside miter joint, use glue and compressed-wood biscuits. Hold the two boards tightly at the outside, marking two places at the joint. The marks should be an equal distance from each other and from the board edge.

Take the boards away, setting the biscuit joiner to be perpendicular to the cut face. Then, adjust the dept of its fence so that it is closer to the back side of the board when you cut. Align the tool’s centerline and perform a slot plunge-cut at the face. For the second mark, repeat.

Step 7: Assemble the Biscuit Joints

Use carpenter’s glue on both slots and over the face of the mitre cut halves. Slip a biscuit into the slot on one of the boards, joining the two boards together. Put the boards back against the wall and use the 8D finish nails on either side of the miter. Between them, drive a 4D finish nail into the joint as well as the end grain on the opposite piece.

Make a scarf joint where the two boards meet on a straight run. Do this by mitering the ends at reverse directions to a point where there’s a stud. Use glue to overlap the miters, nailing through the piece covering the joint but not the joint itself and right into the stud.

Step 8: Nail the Cap Molding

If you plan to use cap moulding, put it on the base to see if it fits snugly right against the wall. Use an 8D nail at a downward angle to secure it at each stud.

If there are gaps and no stud to nail into, you can use construction adhesive on those spots. Just nail the moulding to the wall at those points to set the adhesive.

Step 9: Sanding the Cap Molding

Getting a tight fit at the joints means joining the outside corner with mitres, marking, and cutting as you did in one of the prior steps. Glue those joints together but don’t add nails or biscuits as the molding can split.

Sand all of the mitered corners using fine sandpaper in order to remove the sharp edges. The baseboard trim is now ready to be to go for priming and painting. With a little bit of patience and care, you can install baseboards easily just like a professional and save more than a few bucks in the process.

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