How to Fix a Cracked Window and Avoid a Costly Replacement

Don’t let it crack your bank account

A father and son sitting by the window reading their books
Photo: Tom Werner / DigitalVision / Getty Images
A father and son sitting by the window reading their books
Photo: Tom Werner / DigitalVision / Getty Images
Xiao Faria daCunha
Written by Xiao Faria daCunha
Contributing Writer
Updated Apr 25, 2025
SKILL LEVEL
Simple
COMPLETION TIME
30 minutes
COST
$50 to $100
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What you'll need:
TOOLS
  • Ladder
  • Putty knife
  • Razor blade
SUPPLIES
  • Glass adhesive
  • Paper plates or a cardboard surface
  • Toothpick
  • Acetone glass cleaner
  • Two-part epoxy

Window glass can crack due to various reasons: old glass, inclement weather, or extreme temperature change. Thankfully, you can easily fix a cracked window yourself and avoid costly professional repairs with two-part epoxy. Since epoxy has a short application window, it only takes about 30 minutes per window. Continue reading for step-by-step instructions on how to fix a cracked window yourself.

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  1. Prep the Glass

    Like many other repairing projects, you want to work on a clean surface. The prepping stage also allows you to evaluate the crack and determine if it’s safe to fix it yourself. Use acetone glass cleaner or mix a few drops of dish soap with water to clean the surface. Be sure to remove any dirt, debris, and small glass shards.

  2. Mix the Epoxy

    While waiting for the window to dry, you can start mixing the two-part epoxy. Work in a well-ventilated room and mix on a cardboard or a large paper plate. Use a toothpick or a popsicle stick as your mixing stick. Most two-part epoxies require the resin and hardener to be mixed at a 50-50 ratio, but details may depend on the product. Strictly follow the instructions when mixing. The finished epoxy mixture should look clear and consistent.

  3. Apply the Mixture

    Gently apply the epoxy onto the clean and dry glass with a putty knife. Apply an even layer and avoid spreading the epoxy too thin. Carefully press the epoxy so it fills the crack. You can also use a small rubber spatula for more accurate applications. With most epoxy products, you have about 10 to 15 minutes to apply the mixture before it begins to cure.

  4. Remove Excess Epoxy

    Wait another 10 minutes for curing. Then, remove any excess epoxy using a razor blade to ensure the glass surface is flat and smooth. You can also use a resin remover or glass cleaner to remove excessive epoxy before it fully cures.

  5. Clean the Window

    A man brushes window frame
    Photo: Cavan Images / Cavan / Getty Images

    After the epoxy is fully cured, clean the window again with the glass cleaner. This will polish the glass surface and minimize the crack’s visibility. You can also add a protective film to the glass for additional sturdiness after the repair.

Mistakes to Avoid

The most common mistake when fixing a cracked window yourself is underestimating the urgency of the matter. Cracked windows must be repaired as soon as possible so the fissures don’t worsen and result in the glass shattering.

Also, when working with two-part epoxy, it’s crucial to strictly follow the instructions and allow proper curing time. Insufficient curing would lead to the epoxy not properly filling the crack or even peeling off the surface. Do not touch the epoxy until it is fully cured.

When to Fix a Cracked Window Yourself

Only fix a cracked window if you believe it’s safe. For example, if you only see one clean crack on the glass. If a crack is only on the surface and does not penetrate through the glass, you can usually repair it yourself. Before attempting a repair, gently tap the glass to make sure it’s not on the brink of shattering. If that’s the case, replacing the glass altogether would be a much wiser choice.

DIY vs. Hiring a Pro

You can patch up a cracked window fairly easily yourself, although two-part resin is toxic, especially if you get it on your skin. Properly mixing epoxy can also be challenging if you’ve not worked with the product before. Factoring in the severity of cracking and the risk of the glass shattering, we recommend that you hire a window repair company to fix a cracked window.

If you plan on upgrading your window treatment sets at the same time, a professional subcontractor can make sure everything is taken care of in one project. For example, exterior plantation shutters can effectively prevent your windows from shattering due to storms or other inclement weather conditions.

Frequently Asked Questions

Windows can crack for various reasons. Common causes include aging glass, physical impact, and temperature stress. A less common reason is pressure changes, which are far less predictable. Pressure changes often happen because of poor window placement.

For small, non-pressure-related cracks, you can fix them using two-part epoxy. This spares you the cost and hassle of replacing the glass. Simply clean the surface and remove any debris or dirt, wait for the glass to dry, then spread an even layer of mixed epoxy solution over the crack. You can use a putty knife or rubber spatula to push the epoxy into the crack.

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Learn more about our contributor
Xiao Faria daCunha
Written by Xiao Faria daCunha
Contributing Writer
Xiao is a full-time writer giving advice and tips on improving living spaces so it functions as a peaceful sanctuary and an efficient factory. She is visual artist with substantial woodshop experience and isn’t afraid to pick up a circular saw. She is also a volunteer builder for Kansas City’s Habitat of Humanity.

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