Replacing Glass in Aluminum Window: Step-by-Step Tutorial for Easy Repair

This tutorial demonstrates how to swap out damaged glass in an aluminum window frame effectively, ensuring your home’s aesthetics and insulation are restored.

Key takeaways:

  • Measure the window accurately to ensure a snug fit.
  • Safely remove old glazing compound and glass from the frame.
  • Apply glazing compound to create a solid bed for the new glass.
  • Replace the glass and secure it with new glazing points.
  • Allow the compound to dry and paint for added protection.

What You Will Need

what you will need

To ensure a smooth replacement of glass in an aluminum window frame, having the right tools and materials on hand is crucial. You’ll require:

  • Safety Gear: Don essential protective equipment, such as gloves and safety glasses, to prevent injury from glass shards.
  • Tape Measure: To accurately determine the size of the glass needed.
  • Glass Cutter or Glazier’s Diamond: For scoring old glass to facilitate removal or cutting new glass to size.
  • Putty Knife or Glazing Tool: These are instrumental for removing old glazing compound and applying new.
  • Heat Gun or Blow Dryer: A helpful tool for softening old glazing compound, making it easier to remove.
  • Replacement Glass: Cut to the precise measurements of the window opening.
  • Glazing Compound: Acts as a sealant and cushion for the glass within the frame.
  • Clean Rags: For wiping away debris and cleaning the frame before installing new glass.
  • Caulking Gun and Waterproof Sealant: Essential for sealing the edges to prevent water infiltration.
  • Glazier’s Points or Clips: These small tools hold the glass in place while the glazing compound dries.

This list compiles the essentials, ensuring you are prepared to tackle the task at hand efficiently and effectively.

The Step-By-Step Process

Begin by donning safety glasses and gloves. Safety first—sharp glass shards are dangerous.

First, measure the pane precisely, noting width and height. Purchase replacement glass matching these dimensions exactly.

Next, remove the window sash from the frame to safely extract the broken pane. Use a screwdriver to pry out the old glazing points or clips.

Carefully lift out the broken glass. If it’s stubborn, gently tap it with a hammer handle until it dislodges.

Once clear, clean the frame of all debris, old putty, or silicone. A clean frame ensures a strong seal with the new glass and compound.

Apply a thin bead of silicone caulk or fresh glazing compound along the frame where the glass will sit. This creates a cushion for the pane and seals out moisture.

Carefully place the new glass into the frame. Press it firmly into the compound or caulk without excessive force to prevent breakage.

Insert new glazing points every few inches around the frame to secure the pane. These should be flat and flush against the frame.

Apply a layer of glazing compound around the edges of the pane, smoothing it with a putty knife to create a watertight seal and neat finish.

Allow the compound to dry as indicated by the manufacturer—generally, this is several days.

Lastly, paint the dried glazing compound to match the surrounding frame, which also adds an extra seal against the elements.

Reinstall the sash into the window frame, checking that it operates smoothly and seals correctly.

Step 1: Measure the Window

Accuracy is key when measuring for replacement glass. Use a tape measure from inside edge to inside edge, both horizontally and vertically, at the points where the glass fits into the frame. Record the smallest measurements to ensure the new pane will fit snugly.

Subtract 1/16 to 1/8 inch from each measurement to allow for expansion and contraction due to temperature changes. Double-check numbers to avoid the costly mistake of cutting glass to the wrong size.

If the window frame is not square, measure diagonally to check for squareness. If the diagonal measurements differ, use the smallest measurement for glass cutting to guarantee a proper fit.

Step 2: Remove the Existing Glazing Compound and Glass

Wearing safety gloves and goggles is imperative during this process to protect from sharp edges and potential breakage. Begin with a putty knife to carefully pry the glazing compound away from the frame. This compound may be hardened over time, requiring gentle tapping on the tool with a hammer to loosen the material.

Once the glazing is removed, focus on the glass. If it’s intact, apply tape in an X shape across it to prevent shattering. Firmly but cautiously press the glass from the edges to free it from the frame. It’s possible that the glass might resist; if this happens, use a glass-cutting tool to gently score around the perimeter to break the seal.

For broken panes, clear away shards by hand, starting with larger pieces. Sweep debris from the window frame to ensure a clean surface for the new glass. It’s advisable to work methodically to avoid any injury and to preserve the integrity of the aluminum window frame for the new installation.

Step 3: Seal The Entire Frame With Glazing Compound

After clearing the frame of old glass and residue, preparing the surface is critical for a waterproof seal and to support the replacement glass securely. Begin by applying a thin, even layer of glazing compound around the entire frame. This acts as both a cushion for the glass and a sealant to prevent water from infiltrating. Press the compound into the frame with a glazing tool or putty knife, ensuring there are no gaps or air pockets. The compound should be smooth and consistent, creating a solid bed for the new pane. Remember, this step not only guarantees a snug fit but also contributes to the overall thermal efficiency of your window.


Can you replace one piece of glass in a window?

One piece of glass in a window can certainly be replaced provided the frame is intact and undamaged.

Can you replace the glass in aluminum windows?

Yes, the glass in aluminum windows can be replaced and generally, this task can be accomplished while the glass is still within the frame.

Can you replace glass in a window without replacing whole window?

Yes, it is indeed possible to replace the glass in a window without replacing the entire window, as installing clear, heat-retaining, insulated glass units (IGU) provides a faster, simpler, and more cost-effective solution to problems such as a broken pane.

Is it possible to replace the glass in a double-pane aluminum window?

Yes, you can replace the glass in a double-pane aluminum window, though it takes professional skills and specialized tools to do it correctly.

Which type of replacement glass is recommended for an aluminum window frame?

Tempered glass is recommended for aluminum window frames due to its high durability and safety features.

Is it more cost-effective to replace the glass or the entire aluminum window?

Replacing the entire aluminum window is typically more cost-effective, as it ensures longer lifespan and better insulation.