How To Remove a Commercial Glass Window

Whether you’re replacing a cracked storefront pane, upgrading to insulated glass, or renovating a commercial space, knowing how to safely remove a commercial glass window is a critical first step. Before removing any glass, it’s important to identify the window type and have the correct tools and process in place.

Safety note: Commercial glass panels are heavy, often fragile, and can cause serious injuries if mishandled. Always wear cut-resistant gloves and safety glasses. For large panels or insulated glass units, working with a second person is strongly recommended. When in doubt, call a professional glazier.

Step 1: Identify the Window Type

Not all commercial windows are the same. Understanding what you’re working with will determine the tools and technique you need.

Single Pane Glass

Simple and common in older commercial buildings. A single layer of glass set into an aluminum or steel frame. Relatively straightforward to remove.

Insulated Glass Units (IGUs)

Double-pane windows with a gas or air-filled space between the panes for insulation. More common in modern commercial construction. IGUs require more care during removal — the seal between panes must remain intact if you’re reusing the unit, or the unit should be handled as one piece during disposal.

Fixed vs. Operable

Fixed windows are permanently set in the frame with no opening mechanism. Operable windows (awning, casement, sliding) have hardware that must be removed before the glass can be extracted.

Step 2: Gather Your Tools

Before starting, have the following on hand:

Safety glasses and cut-resistant gloves
Utility knife with fresh blades
Caulk remover or oscillating tool
Screwdriver or drill (with appropriate bits)
Pry bar or glazier’s knife
Suction cups (at least two — more for large panels)
Drop cloth or padded surface for laying down the glass

Step 3: Remove Fasteners

Begin by identifying and removing any fasteners, brackets, or clips securing the glass or frame. Look for:

Glazing stops — The trim pieces (usually aluminum) that hold the glass in the frame. These are typically screwed or snapped into place.
Screws or bolts — In framed systems, the glass may be secured by screws at the frame corners or along the perimeter.

Use a screwdriver or drill to remove screws carefully. Set aside all hardware — if you’re reinstalling the same window, you’ll need these pieces.

For snap-in glazing stops, use a thin pry bar or glazier’s tool to pop them off without bending. Start at a corner and work your way around.

Step 4: Remove the Sealant

Most commercial windows are sealed with silicone caulk, glazing compound, or butyl tape. This seal must be cut before the glass can be removed.

Using a utility knife, score along the entire perimeter of the glass where it meets the frame.
Run the knife multiple times if the sealant is thick or dried.
For stubborn silicone, use an oscillating tool with a blade attachment to cut through more efficiently.
Avoid cutting too deep — you want to cut through the sealant, not scratch the frame or surrounding surfaces.

Work slowly and methodically. Rushing this step often results in cracked glass.

Step 5: Loosen and Extract the Glass

With the stops removed and sealant cut, the glass should be ready to come out. Here’s how to do it safely:

Attach suction cups to the face of the glass — one near each top corner, and additional cups near the bottom for larger panels.
Apply gentle, even pressure to push the glass outward (or inward, depending on which direction it’s set).
Use a glazier’s knife or thin pry bar to carefully break the bond along the perimeter if the glass is still stuck.
Once it starts to move, lift the panel straight out using the suction cups. Keep the glass vertical to prevent stress cracking.
Immediately place the glass on a padded surface or secure it upright against a wall.

For large or heavy panels: Always have a second person helping — one person holding the suction cups and guiding, the other supporting from the bottom.

Step 6: Replacing Double-Pane Glass

If you’re removing a double-pane (IGU) unit for replacement, follow these additional steps:

If the window has a sash, remove the sash from the frame before extracting the glass.
In a fixed frame, remove the glazing stops first, then carefully lift the IGU straight out.
Clean the frame thoroughly — remove all old sealant, dirt, and debris.
Insert the new IGU of the same size and thickness.
Use glazing tape or fresh silicone to set the glass, then reinstall the stops.
Ensure the seal is completely airtight to prevent condensation forming between the panes.

When to Call a Professional

While removing a single-pane window is manageable for experienced DIYers, there are situations where calling a professional glazier is the right call:

Large panels — Storefront glass panels can weigh hundreds of pounds and require specialized lift equipment.
Curved or specialty glass — Non-rectangular shapes need custom handling and equipment.
High-rise or elevated work — Any work above ground level that requires a lift or scaffolding.
Structural glazing — Glass that is bonded to the frame with structural silicone (common in curtain wall systems) requires specialized removal techniques.
Tempered or laminated glass — While safer to handle, these glass types require proper disposal procedures.

Need Commercial Glass Removal or Replacement in Clarksville?

Allnite Glass has been handling commercial glass installation, repair, and replacement for businesses in Clarksville, Nashville, and Hopkinsville for over 75 years. Our team can safely remove and replace any type of commercial glass system — from single-pane storefronts to multi-story curtain walls.