How to Trim an Arch Top Window

Written by samantha volz
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How to Trim an Arch Top Window
Arched windows need flexible moulding to complete an elegant look. (Jupiterimages/ Images)

The look of an arched window or door frame creates a cathedral-like style to your home, and adding decorative trim to the area will complete a look of finished elegance. However, most wood trim is solid and cannot be bent and manipulated to fit an archway, leaving the homeowner with limited options for finishing techniques. Many manufacturers now produce flexible trim moulding, which can be painted or stained to resemble solid wood but is composed of plastic or vinyl to make it bendable. This material must be securely attached in place to complete the look of your window.

Skill level:
Moderately Easy

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Things you need

  • Sponge or rag
  • White spirit
  • Sandpaper
  • Construction adhesive

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  1. 1

    Layout the material in the installation area for at least 24 hours to allow it to adjust to temperature and humidity level.

  2. 2

    Clean the archway with a sponge or rag dampened in white spirit to remove surface contaminants, which could ruin the way the adhesive bonds to the surface.

  3. 3

    Inspect the archway for any broken areas or spurs. If necessary, sand pointy areas with fine-grit sandpaper to avoid damaging the flexible trim material.

  4. 4

    Spread a small bead of construction adhesive across the entire back area of the flexible trim, working in a constant "S" shape all across the back.

  5. 5

    Press one end of the trim firmly in place and gradually work your way around the arched window, applying firm, even pressure over the entire trim piece to secure it to the archway.

  6. 6

    Clean any excess adhesive from the edges of the trim with a rag or sponge dampened in white spirit. Allow the adhesive to dry for 24 hours before exposing the area to any moisture.

Tips and warnings

  • If you intend to paint or stain your flexible trim, do so after it is installed, to avoid cracking or straining the finish during installation.
  • Read and follow all specific installation instructions for your chosen product. Some products may require you to nail or staple the material into place along with the gluing procedure.
  • Cut flexible trim moulding to fit as necessary with a hand saw, circular saw or mitre saw.

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