How to Replace a Window Grille Divider in an Exterior Door

Introduction

Replacing a window grille divider in an exterior door can seem daunting, but it’s an achievable DIY project for most homeowners with some basic tools and a bit of time. Window grille dividers, also called muntins, help break up the glass into smaller panes for a classic divided lite look. Over time, these grille dividers can warp, crack, or fall out completely. Replacing them not only restores the aesthetic appeal of your front door, but also enhances privacy and security.

In this comprehensive guide, we’ll walk through the entire process of removing the old grille dividers and installing new ones step-by-step. We’ll cover how to remove the door sash, get accurate measurements, cut and fit the new muntins, seal and install the glass panes, and rehang the door securely. With the right materials and some patience, you can give your exterior door an updated look with new window grille dividers.

Things You’ll Need

Before starting this project, gather the necessary materials:

Phillips screwdriver
Flat pry bar
Tape measure
Pencil
Safety glasses
Work gloves
Sandpaper
Wood glue
Paintable silicone caulk
Wood putty
Paintbrush
Replacement grille muntins
Glass panes cut to size
Shims
Door handle assembly

Make sure you have all the right tools and materials on hand before beginning. This will allow the project to go smoothly from start to finish. Safety gear like glasses and gloves are also a must when working with glass.

Removing the Old Door Sash

The first step is to remove the current door sash so you can access the window grille dividers. Follow these steps:

1. Unscrew the Door Handle Assembly

Use a Phillips screwdriver to remove the screws securing the door handle and lockset. Set aside all hardware.
Carefully pull the interior handle and lockset away from the door. Detach any latching mechanisms.
You may need to pry off decorative plates gently with a flat bar. Prevent scratches by padding the pry bar tip.

2. Remove Decorative Trim and Casing

Pry off any interior moulding or casing around the glass pane using a flat bar. Pad the tip to prevent marring the wood.
Label pieces to ensure proper reinstallation later. Set trim aside safely.

3. Extract Exposed Screws

Use a screwdriver to remove any exposed screws now visible around the window frame.
These likely secure the fixed sash in place within the door.

4. Release the Fixed Sash

Insert shims incrementally around the interior edge of the fixed sash. Apply even pressure to loosen the frame without cracking the glass.
Support the sash as you work shims around the perimeter to prevent sudden dropping.
The goal is to free the sash enough to lift it out fully.
Remove the fixed sash and set it aside carefully once freed. Avoid contact with the glass edges.

You now have access to the window grille muntins ready for replacement.

Taking Accurate Measurements

With the fixed sash removed, take precise measurements of the grille dividers to ensure proper sizing of replacements:

1. Measure Overall Opening Size

Measure the overall height and width of the glass opening. Write down measurements.
Confirm the size by measuring diagonally from corner to opposite corner. These measurements should match if the opening is square.

2. Count and Measure Each Grille Piece

Count the number of vertical and horizontal muntins in the existing grillework.
Measure the length of each vertical divider. Make sure they are all the same.
Measure the height of each horizontal muntin. Confirm consistent sizing.
Note the width and depth of each grille piece as well.

Accurate measurements ensure your new muntins will fit correctly within the door opening. Avoid loose or gaping fits.

Cutting Replacement Muntins to Size

With your measurements, you can now cut new grille pieces to size:

1. Buy Muntin Material

Purchase enough grille divider stock to cut all required pieces. Options include wood, plastic, or aluminum.
Wood blends most naturally if stained to match door. Plastic is economical. Aluminum has straight edges but lower visual appeal.

2. Cut Vertical Pieces

Lay out measured lengths on muntin material with pencil. Allow 1/8″ extra length for snug fits.
Clamp stock securely to a work table. Use a miter saw or handsaw to cut muntin pieces to measured vertical lengths per your counts.

3. Cut Horizontal Pieces

Repeat process, marking and cutting horizontal muntin stock to the measured window pane heights, plus 1/8″ extra.
Cut the same number as original grillwork.
Lightly sandcut edges to remove sharp burrs or snags.

The new muntins should now match the original sizes and layout when test fitted into the opening.

Fitting and Installing the New Grillework

With all pieces cut to size, you can install them into the door’s glass opening:

1. Dry Fit the Grille Layout

Do a dry run by placing muntins into opening to ensure proper fit.
Make minor adjustments with light sanding if needed.
Ensure grille bars meet neatly at corners. Cut mitered edges if desired for seamless joints.

2. Apply Glue to Muntin Joints

Run a thin bead of wood glue along the back side of muntins where they intersect.
Assembly will be permanent once glue sets.
Wipe away any excess squeeze-out immediately with damp rag.

3. Secure New Grillework in Place

Set glued muntins back into place along frame opening. Make sure orientation matches original layout.
Tack each muntin lightly into the door frame opening while the glue sets. This keeps them from shifting out of position.
Allow several hours for the glue to fully cure and bond grille joints securely.

The new window grille muntins should now be installed securely into the door’s glass opening.

Installing New Glass Panes

With fresh grille dividers in place, you can now install new glass panes:

1. Measure and Order Glass

Take precise measurements of each window section created by the grillework.
Order tempered glass cut to these sizes.
Have edges sanded or polished.

2. Apply Perimeter Sealant

Run a thin, continuous bead of paintable silicone caulk around the inside of the muntin frame.
Create a continuous seal between the glass and grillework.

3. Set Glass into Sections

Place cut panes of glass into each window section, resting on the sealant bed.
Ensure panes are centered within openings.

4. Apply Finishing Sealant

Run another thin bead of caulk around the interior glass edge, sealing it to the muntins.
Tool the sealant with a finger before drying for a smooth finish.
Allow the silicone to fully cure per manufacturer instructions before rehanging door.

The new glass panes should now be sealed securely within the fresh grille divider sections.

Preparing and Hanging the Door

With fresh muntins and glass installed, the final steps are preparing the door for rehanging:

1. Make Any Needed Repairs

Inspect frame and sashes for any damage now accessible. Make repairs as needed.
Fill old screw holes with wood putty. Sand smooth when dry.

2. Prime and Paint Frame

Apply primer to any exposed unfinished wood, putty repairs, and muntins.
Once dry, paint with a finish coat to match existing color.

3. Reinstall Door Hardware

Mount original lockset assembly and handle back into place. Attach any latching rods, plates, or strike plates.
Confirm smooth operation and proper closure.

4. Rehang Door in Opening

Use shims to plumb and square the door frame in the opening.
Anchor hinge screws into jamb. Install any necessary jamb seals.
Test operation of door after hanging to ensure proper closure and fit.

5. Replace Trim and Casing

Clean all dust from the interior edges and glass. Apply caulk if needed between jamb and wall.
Reinstall all interior moulding, casing, and trim removed previously.

With patience and care, your exterior door will have attractive new window grille muntins and glass panes installed properly. Enjoy the renewed curb appeal and decorative flair.

Frequently Asked Questions

Here are answers to some common questions about replacing a window grille divider in an exterior door:

How do I get the grille layout centered in the door?

Take equal width measurements from each jamb to find the vertical midpoint. Use the same method top to bottom. Mark light pencil lines. Align one vertical and horizontal muntin on these centerlines to keep the grille pattern centered.

What’s the easiest material to cut replacement muntins from?

Plastic grille dividers are the most DIY-friendly material. They require simple scoring with a utility knife and snapping along the score line. Wood and aluminum require more specialized tools for clean cuts.

My glass pane broke – can I just replace it?

Unfortunately no – removing one pane risks cracking the surrounding panes. It’s best to replace the entire glass portion at once when feasible. Take it as an opportunity to refresh the dividers and overall look.

My door only has a single large pane – can I add grille dividers?

Absolutely, Many doors can easily be retrofitted with new muntins to create a multi-pane divided lite look. Just follow the steps to remove the sash, measure pane openings, cut pieces and reinstall glass.

How do I keep muntins from rattling against the glass?

Apply small vinyl bumpers to the backs of muntins where they meet glass to prevent rattling. Low tack tape along the length also helps minimize contact and vibration.

Can I stain replacement wood muntins to match my door?

Yes, wood muntins can be stained or painted to blend with the door’s finish. Prepare raw wood properly, then apply gel stain and polyurethane for protection against elements.

How do I clean glass panes sealed between muntins?

Use a soft cloth and mild cleaner on surrounding woodwork. For glass, use a microfiber cloth dampened with warm water and a small amount of vinegar. Dry immediately to avoid streaks.

Conclusion

Replacing worn or damaged window grille muntins in an exterior door restores curb appeal and brings back a stylish divided lite look. While it requires careful removal and reinstallation of the door sash, it’s a project a motivated DIYer can tackle themselves. New grille dividers and fresh glass panes make the entryway feel welcoming once again. Just be sure to measure twice and cut accurately for the best fit. With some patience, the right materials, and these step-by-step instructions, you can achieve a successful window grille replacement. Display your decorative new door design proudly for all to see.