How to Replace a Window Grille Divider in an Exterior Door

Open Front Door
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Project Overview
  • Working Time: 1 hr
  • Total Time: 2 hrs
  • Skill Level: Intermediate
  • Estimated Cost: $75 to $150

Many exterior doors with windows have what appears to be a grid or grille of small window panes. But in most modern doors, that look is accomplished by a single pane of thermal grass with plastic surface frames mounted on the surface of the glass, inside and outside. These frames create the appearance of authentic "divided-lite" windows with muntins that separate individual glass panes. If this grille frame is damaged, you can simply replace the entire frame.

These muntin grille frames are typically sold as kits that include both interior and exterior frame halves. You can find replacement kits at home centers and online retailers, or contact the door manufacturer for a replacement part. 

What You'll Need

Equipment / Tools

  • Utility knife
  • Screwdriver
  • Putty knife
  • Razor scraper
  • Caulking gun


  • Replacement grille frame
  • Glass cleaner
  • Clear silicone caulk
  • Rubbing alcohol
  • Clean rags


  1. Cut the Paint Film

    Use a utility knife to cut through the paint film where the grille frame meets the door, starting at one corner and working around the perimeter. Cut just deep enough to break the paint or caulk that seals the grille frame to the door.

    scoring inside of window frame for removal
  2. Remove the Grille Frame Screws

    Remove the screws that hold the exterior and interior halves of the plastic grille frame together. These screws are found on the interior half of the grille frame. If the screws are concealed beneath plastic plugs that are hard to remove, drive another screw into the plug about 1/4 inch, then pull the screw straight out with the plastic plug attached.

    screws holding frame in place
  3. Remove the Grille Frames and Glass Panel

    Remove the interior grille frame. You may have to use a putty knife or similar thin-blade tool to get under the frame to gain leverage. Remove the exterior frame and glass panel from the door; they generally come out as one piece since they are joined together with adhesive. This may require that a helper push on the glass from the inside while you support the glass from the exterior side.

    removing glass frame from door
  4. Separate the Exterior Grille Frame

    Lay the glass panel and grille frame on a flat work surface with the grille frame facing up. Carefully separate the frame from the glass panel, using a putty knife or razor scraper to cut through any old caulk.

    exterior door window panel
  5. Clean the Glass

    Use a razor scraper to clean the glass of all old paint and adhesive residue on both sides. Keep the razor's edge flat on the glass so as to avoid scratching it. Clean the glass panel with glass cleaner. 

    cleaning window of old paint
  6. Prepare the New Grille Frame

    Separate the two halves of the replacement grille frame assembly and place the half with no screw holes (the exterior side) face down on your work surface.

    preparing new window muntins
  7. Apply Caulk to the Exterior Grille Frame

    Apply a continuous bead of clear silicone caulk around the inside surface of the grille frame's perimeter. This caulk bead will seal the frame to the glass.

    silicone on glass
  8. Set the Glass Panel Onto the Grille Frame

    Carefully lay the glass unit onto the exterior half of the plastic grille frame, and press the window into place. Expect some caulk to ooze out.

    glass on muntins
  9. Install the Window Unit

    From the outside face of the door, carefully lift the exterior frame and glass assembly into the door opening. Have a helper hold the unit in place from the outside while you position the interior half of the grille frame on the inside of the door and secure the two halves with the provided screws. 


    The interior half of the frame does not need to be caulked.

    attached window to door
  10. Finish the Installation

    Using a clean rag moistened with rubbing alcohol, wipe away any caulk that has oozed out around the frame. Dried caulk can be removed with a razor scraper.

    Insert the plastic screw hole plugs that came with the kit, as applicable, to conceal the screw heads.

    screw plugs