8 Steps to Perfectly Installed Quarter Round Trim

Prepare the Quarter Round

It’s easier to paint or stain trim work before you install it. (If you purchase pre-finished quarter round, you can skip this step.)

Support several pieces of quarter round on sawhorses, workbench, or another sturdy surface. Protect the floor from drips with a drop cloth.

Stain or prime and paint the curved surface of the trim piece. Allow curing overnight if painting.

Measure the Length

Measure to the nearest 1/16-inch when using a tape measure. Err on the side of being too long rather than too short.

Cut the Quarter Round

To master quarter round installation, you’ll need to learn three types of cuts: a butt cut, a 45-degree cut, and a coped join cut.  

A butt cut is a cut that’s exactly perpendicular to the length of the quarter round. Set the miter saw angle to zero degrees and line the trim piece up to the saw’s fence to cut. 

You’ll use 45-degree cuts for making corners and scarf joints. Set the miter saw’s angle to 45-degrees in the direction you need. Place the quarter round in the saw with one of its flat edges against the fence.

Coped joint cuts create seamless inside corners. To make the joint, cut the end of the trim at 45-degrees so that the cut profile is facing you. With a coping saw or jigsaw, turn the blade away from the angled cut and saw along the leading edge of the profile line.

When complete, you’ll have an end that matches the profile of the quarter round.

Install the Quarter Round

Work slowly and carefully if you are staining your quarter round or using pre-finished pieces. There won’t be an easy way to hide mistakes in the end. 

Nail through the quarter round and into the baseboard behind it. Avoid nailing into the flooring or subfloor.

Except on outside corners and scarf joints, avoid using glue to install quarter round. You may need to remove the trim later to work on the floor, and gluing will make disassembly difficult, if not impossible.

Create an Outside Corner

Make a 45-degree cut facing away from you on the miter saw. Place the piece along the baseboard so that the inside of the cut is at the baseboard’s corner. 

Cut an opposite 45-degree angle in another piece of trim. It’s best to cut this piece slightly longer than you need and make several minor cuts until you reach the exact length. In other words, “creep up” on the measurement. 

Apply wood glue to the meeting edges and set the second piece in place. Use the nail gun to fire a trim nail through the quarter round and into the baseboard near the corner. Repeat on the other side of the corner and wipe away excess glue with a disposable rag.

Create an Inside Corner

There are two ways to create an inside corner, and you may find yourself using both methods. 

A simple inside corner joint is the opposite of an outside corner. Cut opposing 45-degree angles in two pieces of quarter round and use a nail through each to install. This method works only for corners that measure precisely 90-degrees. 

For corners that don’t measure exactly 90-degrees, make a butt cut in the first piece of quarter round and install it in the corner with the butt end hidden against the opposing baseboard corner. 

Make a coped joint cut in the second piece of the corner and install it with the cut end directly against the profile of the opposing quarter round piece. There’s no need for glue on the inside corners.

Make a Perfect Scarf Joint

If a wall is too long for one piece of trim to span the distance, you’ll need to create a scarf joint to extend the length of the trim work. 

To do this, make a 45-degree cut facing towards you on the miter saw. Install the piece in place, but refrain from nailing the last couple feet. 

Make an appropriate cut on the opposite end from the scarf joint for the second piece. Set the piece in place and mark the scarf joint cut with a fine pencil line. Cut the opposite 45-degree angle. Again, cut the piece slightly too long and creep up on the final cut length.

Apply glue to the joint ends where they meet. Complete the installation by firing a nail directly through the joint and into the baseboard and wiping away excess glue.

Finish the Quarter Round Installation

Photo: Christopher Nuzzaco / Adobe Stock

For stained or prefinished quarter round, use a small amount of appropriately colored wood fill on your finger to rub into each nail hole. 

For painted trim work, fill each nail hole with paintable caulk or wood fill and follow up by touching up the spots with the same colored paint and a small brush.