DIY Window Repair: A Step-by-Step Guide to Replacing Broken Window Glass

Updated at: 10/05/2025

A broken window is more than just an eyesore; it's a security vulnerability and a potential source of drafts, leading to increased energy bills. While calling a professional glazier is always an option, many simple window glass replacements are entirely manageable as DIY projects, saving you time and money. Replacing broken window glass can seem daunting, but with the right tools and a methodical approach, it's a surprisingly achievable task for even novice DIY enthusiasts. This is especially true for common window types found in many homes.

This guide provides a comprehensive, step-by-step process for replacing broken window glass, empowering you to tackle this common home repair with confidence. We'll walk you through every stage, from carefully removing the damaged glass to securing the new pane, ensuring a weatherproof and aesthetically pleasing result. Let's get started with the first crucial step in our DIY window repair journey.

Preparation and Safety Guidelines

Tools Needed
  • Glazing strips
  • Measuring tape
  • Utility knife or scissors
  • Dirty rag
  • Safety goggles
  • Glass spatulas
  • Pen or pencil
  • Gloves
  • Silicone sealant
Safety Guidelines
  • Wear safety glasses and gloves throughout the entire process to protect yourself from sharp glass fragments.
  • Use caution when handling glass; broken pieces can be extremely sharp and cause serious injury. Dispose of broken glass responsibly, preferably in a heavy-duty container.
  • If you're uncomfortable with any step or feel unsure about your ability to complete the repair safely, contact a professional glazier.

Step-by-Step Instructions

  1. Preparation

    • Measure the window at the middle corners of each side horizontally and vertically.
    • Purchase replacement glass, shopping around for the best price.
    • Lock the window.
    Lock the window.Lock the window.Lock the window.
    Preparation

  2. Glass Removal and Cleaning

    • Remove excess glass and glazing carefully, wearing gloves.
    • Clean off old silicone and dirt to ensure good adhesion of the new glass.
    Clean off old silicone and dirt to ensure good adhesion of the new glass.Clean off old silicone and dirt to ensure good adhesion of the new glass.
    Glass Removal and Cleaning

  3. Glazing Strip Preparation

    • Cut the glazing strips to the window dimensions (horizontal straight, vertical slanted).
    Cut the glazing strips to the window dimensions (horizontal straight, vertical slanted).
    Glazing Strip Preparation

  4. Sealant Application

    • Cut the silicone sealant tip at an angle for easier application.
    • Apply sealant to the window where the glass will adhere.
    Apply sealant to the window where the glass will adhere.Apply sealant to the window where the glass will adhere.
    Sealant Application

  5. Glass Installation

    • Apply the glass gently, pressing to avoid breakage.
    Apply the glass gently, pressing to avoid breakage.
    Glass Installation

  6. Glazing and Finishing

    • Apply the glazing strips, using silicone to secure them to the glass and window. Apply horizontal strips first, then vertical, ensuring the lip of the glazing clips into the space between the glass and window frame.
    Apply the glazing strips, using silicone to secure them to the glass and window. Apply horizontal strips first, then vertical, ensuring the lip of the glazing clips into the space between the glass and window frame.
    Glazing and Finishing

Read more: 3M Thinsulate Window Film Installation: A Step-by-Step Guide

Tips

  • Shop around for glass to save money.
  • Use scissors instead of a utility knife for cutting glazing strips; it’s easier.
  • Use smaller spatulas for removing smaller pieces of glazing.
  • Use silicone to secure the glazing, especially helpful for beginners to avoid breaking the glass.
  • Apply horizontal glazing strips first, then vertical ones.

Common Mistakes to Avoid

1. Incorrectly Measuring the Glass

Reason: Measuring incorrectly leads to the new glass being too small or too large, resulting in a poor fit and potential leaks.
Solution: Carefully measure the window opening multiple times using a precise measuring tool and account for the glazing bead's thickness.

2. Using the Wrong Type of Glazing Compound

Reason: Using an inappropriate glazing compound can lead to poor adhesion, cracking, and ultimately, window failure.
Solution: Choose a glazing compound specifically designed for exterior use and appropriate for the type of window frame.

FAQs

What type of glass should I use to replace my broken window pane?
Use glass that matches the thickness and type of your existing window glass. If unsure, take a sample to a glass supplier for matching. Consider using tempered or safety glass, especially for windows near doors or in high-traffic areas.
What tools do I need to replace a window pane?
You'll need a putty knife or glazing tool, a utility knife, a measuring tape, safety glasses, gloves, new glass (cut to size), glazing points (small triangular pieces of wood or plastic), and glazing compound or putty.
What if I break the new glass while installing it?
Carefully handle the glass throughout the process to avoid breakage. If the new glass breaks, you'll have to start over with a new, correctly sized piece. Remember to always wear safety glasses.