How to Trim Arched Windows

Use polyurethane to trim an arched window.

An arched window is a terrific decorative accessory for any room. Adding trim to an arch creates an air of depth and texture around the window. Several methods are used to apply trim to an arched window. One involves the use of polyurethane products. Trim made from polyurethane is flexible and easily manipulated. Many companies design border with arched trim to fit standard size windows. If you require trim for an unusual shape or size window, purchase polyurethane trim and bend it to fit your needs.

Things You'll Need

• Measuring tape
• Pencil
• Paper
• Polyurethane trim
• Heat gun
• Miter saw
• Hand saw
• Medium-grit sandpaper
• Caulking
• Paint

Instructions

1. Select the type of trim you want to install. Making the determination will depend on the type of window you are trimming. Consider the width of the trim and any styles that work with the rest of the decor in the room.

2. Measure the base of the window inside the arch. Place the measure on the left side of the window just before the curve begins, and stretch it horizontally across to the same area on the right side. Write the measurement down

3. Determine the tallest region of the arch. Look towards the center of the window. Arched windows are symmetrical. The center region will be the tallest section. Stretch your measures from the bottom center of the window to the top of the arch, which is the arch radius of your window. Record this number with the base measurement.

4. Take your measurement with you to the home design store. Select trim that works with the style window. If the trim does not fit exactly, purchase trim made of polyurethane so you can cut or bend it.

5. Heat the trim using a heat gun, which will work well if you have a small piece of trim. Once heated, the polyurethane will bend to the shape you need. Hold the gun approximately one foot away from the unpainted trim. Once trim warms, bend it around your window frame so that it fits to the arch. Let the trim cool in the correct shape. Sand and paint the trim as needed before installing it.

6. Cut large trim lengthwise with a miter saw or hand saw. A thinner piece of trim will bend easier. For instance, Cut a piece that is four inches thick horizontally to create two-inch strips. Use a heat gun to bend the trim as described above. Try to cut along a seam or elevation in the trim. Trim this thick will likely have levels. The center will be thin and have elevated borders. Cut the borders off so you can bend them separately.

7. Cut the trim into sections. Make select vertical cuts along the trim with a saw. Apply caulking between the cut areas. With this method, the cuts themselves become the flexible agents. Lay the trim out, and make your cuts. Attach the second piece to the first, filling the space between the two pieces with caulk. Use the caulk to create your arch. The deeper the arch, the more pieces you will need to cut. You can combine several methods to apply long, thick trim. You may need to cut each individual piece lengthwise to separate the borders and work with a short thin piece. Use the heat gun to create a bend, and attach the trim together in the proper shape with caulk. Once you have the properly arched trim, reattach with caulk, let the caulking dry. Sand the trim, and paint it before attaching it to the wall around your window.

References

• Blinds: Measuring For Arches & Skylight Shades
• Wish I Had That: How to Install Molding on an Archway
• Wish I Had That: Arched Moldings