How To Replace Glass in a Door

Replacing broken glass in a door is a manageable DIY project that can enhance your home’s safety and appearance.

In this article and accompanying video, This Old House general contractor Tom Silva shows us how to remove old glass, take measurements, and install a new pane in a wooden door in just a couple of hours.

Understanding Door Glass Replacement

Door glass replacement requires careful handling and precise measurements to ensure a proper fit and safe installation.

Types of Door Glass

Not all glass is made equal. Since doors must withstand the impact of repeated closings, the glass in them must include safety features that will keep it from shattering. In the video, Silva recommends laminated safety glass with a plastic layer between the panes to keep the glass together if it breaks.

If security is an issue, you can also opt for wired glass, though it will be a bit more expensive. Tempered glass is also an option. It’s stronger than plate glass, and should it shatter, it breaks into small cubes that are less dangerous than shards. Above all, you should avoid decorative or plate glass for doors and check local building codes for anything other than tempered or safety glass.

Tools and Materials Needed

Gather the following tools and materials prior to starting your project:

• Caulk gun
• Glazing compound
• Glazing points
• Hammer
• Nailset
• New glass pane
• Putty knife
• Safety glasses
• Tape measure
• Replacement wood stops (if needed)
• Wood filler
• Work gloves
• Wire brads

Removing the Old Glass

The first step in replacing door glass is carefully removing the broken or old pane. This process requires patience and attention to detail to avoid damaging the door frame or injuring yourself.

Preparing the Work Area

Before beginning, take the following setup and safety steps:

• Ensure proper ventilation in the work area
• Have a trash bag ready for glass disposal
• Lay a drop cloth beneath the door
• Wear safety glasses and work gloves

Removing the Stops and Glass

This process applies to windows with wooden stops. Other door and window materials may require a different removal process.

Here’s how to remove the old glass:

1. Use a stiff-blade putty knife to pry the wooden stops from around the broken pane.
2. Carefully remove the broken pane from the door, supporting it to prevent falling.
3. Dispose of the old glass safely in a sturdy trash bag.

Work gently to remove the wood stops without breaking them so you can reuse them with the new glass. If this is impossible or the wood is rotten or damaged, replace them with new stops.

Preparing the Door for New Glass

Once you’ve removed the old glass, you’ll prepare the door frame for the new pane by cleaning it and measuring the replacement piece.

Cleaning the Frame

Proper cleaning ensures that the new glazing compound adheres well, providing a long-lasting and secure fit. Neglecting this step can result in poor adhesion, which can cause potential leaks and decreased insulation efficiency.

1. Scrape away the old glazing compound from the windowpane opening.
2. Remove any remaining glazing points or debris.
3. Clean the frame thoroughly to ensure good adhesion for the new glazing compound.

Measuring for the New Glass

Accurate measurements are essential for a proper fit. Measure the opening from stop to stop on all sides, but subtract one-eighth of an inch from each measurement to allow for expansion and contraction. Silva recommends this slight reduction in size to prevent the glass from cracking due to pressure from the expanding wood frame.

Installing the New Glass in a Door

Now that you’ve prepped the frame and cut your glass to size, you can install the replacement pane. 

Applying Glazing Compound

Run a thick bead of glazing compound around the pane opening to create a proper seal. Take extra care to distribute the compound evenly, building a uniform bed for the glass.

An even application of the glazing compound will ensure that the glass sits securely and evenly in the frame, reducing the risk of leaks, drafts, and breakage.

Setting the Glass

We recommend getting a helper to hold the new glass in place while inserting the glazing points. Take these steps to set the new pane:

1. Carefully place the glass into the prepared opening.
2. Press the glass gently but firmly into the glazing compound.
3. Secure the glass with glazing points, spacing them evenly around the perimeter and pushing them into the wood frame with a putty knife.

Reattaching the Stops

To complete the installation, do the following:

1. Reattach the wooden stops with wire brads. For easier nailing, start the brads into the stops before placing them into the window.
2. Tap the brads below the wood’s surface using a nailset and hammer.
3. Fill any nail holes with wood filler and sand smooth once dry.

Glass Door Finishing Touches

Proper sealing prevents moisture from entering the frame, which can cause damage over time. It also helps improve the door’s insulation properties.

Here’s how to weatherproof the new installation:

1. Apply a thin bead of glazing compound around the edges of the glass where it meets the stops.
2. Smooth the compound with a putty knife for a neat appearance.
3. Allow the compound to dry according to the manufacturer’s instructions.
4. Clean both sides of the glass thoroughly.
5. Inspect the sealant for any gaps or imperfections.

Maintenance Tips

Routine maintenance extends the life of your door glass, ensuring it remains functional and aesthetically pleasing for years.

Keep your newly replaced door glass in top condition by regularly cleaning it with a non-abrasive cleaner, inspecting the glazing compound annually for signs of cracking or shrinkage, and repainting or restaining the wooden stops as needed to protect them from moisture.

Additional Tips for Success

For a smoother project, our experts recommend using these tips:

• Measure carefully: Incorrect measurements can lead to improperly fitting glass, causing delays and added costs.
• Seek help if needed: If the door or glass pane is particularly large or heavy, don’t hesitate to ask for help to avoid accidents or injuries.
• Use high-quality materials: Investing in quality glazing compound and brads can significantly improve the durability of your installation.
• Work in good weather: Try to replace glass on a dry day. Moisture can interfere with the adhesion of the glazing compound.

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