How to Add Trim to an Arched Doorway

Transforming a plain doorway into an elegant arched one can significantly enhance the aesthetic appeal of your home. But what if you want to take it a step further and add trim to your arched doorway? Don't worry, with the right tools and a bit of patience, you can achieve this DIY project. Let's dive into a step-by-step guide on how to add trim to an arched doorway.

Before you start, ensure you have all the necessary tools and materials. You'll need a miter saw, a jigsaw, a tape measure, a pencil, sandpaper, wood glue, finish nails, and of course, the trim of your choice. For this guide, we'll assume you're using crown molding, a popular choice for doorways.

Preparation and Measurement

Accurate measurement is key to a successful trim installation. Start by measuring the width and height of your doorway. The width will determine the length of your side pieces, while the height will help you calculate the length of your header piece.

Next, measure the radius of your arch. This will help you determine the length of your arch piece. Remember to account for the thickness of your trim when making these measurements.

Cutting the Trim

Side Pieces

Using your miter saw, cut the side pieces to the width of your doorway. Since you're working with an arched doorway, these pieces will be straight.

Before installation, test fit these pieces to ensure they fit snugly against the sides of your doorway.

Header Piece

Cut the header piece to the height of your doorway. This piece will sit above the arch, so it doesn't need to be arched itself. However, you will need to miter the ends to fit against the side pieces.

To do this, set your miter saw to a 45-degree angle and cut the ends of the header piece. Test fit this piece to ensure the miters fit snugly against the side pieces.

Arch Piece

Cutting the arch piece is a bit more complex. You'll need to create a compound miter cut, which involves cutting at two different angles. First, set your miter saw to the same angle as your arch. Then, adjust the bevel angle to match the angle of your arch.

Cut the ends of your arch piece at these angles. Test fit this piece to ensure it fits snugly against the side and header pieces.

Installing the Trim

Side Pieces

Starting with the side pieces, apply wood glue along the back edge of each piece. Then, using finish nails, attach each piece to the side of your doorway. Ensure they're level and plumb as you go.

Once both side pieces are installed, use a nail set to countersink the nails below the surface of the wood. Then, fill these holes with wood filler and sand smooth.

Header Piece

Next, install the header piece. Apply wood glue along the back edge and the mitered ends. Then, using finish nails, attach the piece to the top of your doorway and the mitered ends to the side pieces.

Again, use a nail set to countersink the nails and fill the holes with wood filler. Sand smooth once the filler is dry.

Arch Piece

The arch piece is the most challenging to install. Start by applying wood glue along the back edge and the mitered ends. Then, using finish nails, attach the piece to the top of your doorway and the mitered ends to the side and header pieces.

Use a level to ensure the piece is properly aligned. Once it's in place, use a nail set to countersink the nails and fill the holes with wood filler. Sand smooth once the filler is dry.

Congratulations! You've successfully added trim to your arched doorway. Now, step back and admire your handiwork. If you're feeling adventurous, consider painting or staining your trim to match your home's decor. But for now, enjoy the satisfaction of a job well done.