Glass, Style

How to Reseal a Leaking Window Glass Unit

Posted on by mala mogodu
How to Reseal a Leaking Window Glass Unit - Get Glass
19
Jun

Over time, even well-installed windows can start to leak due to worn-out seals, poor installation, or extreme weather conditions. Knowing how to reseal a leaking window glass unit can save you from the cost of a full replacement when the frame and glass are still in good shape. These leaks often lead to drafts, moisture intrusion, and even mold growth around the window frame.

This guide will show you how to identify the source of the leak and apply the proper resealing technique to restore your window’s weatherproofing.

Common Signs of a Leaking Window

  • Water stains or damp spots near the window sill
  • Drafts when the window is closed
  • Condensation between double-glazed panes
  • Loose or cracked sealant or caulking
  • Whistling noise during windy weather

Why Windows Leak

Some of the most common causes include:

  • Old or damaged window seals
  • Shrinking or cracked glazing gaskets
  • Poor initial installation
  • Movement in the wall or frame due to age
  • Exposure to heavy rains or UV damage over time

Tools & Materials You’ll Need

Step-by-Step: How to Reseal a Leaking Window Glass Unit

Step 1: Inspect and Identify the Leak

  • Check the entire perimeter of the glass and frame.
  • Look for cracked sealant, loose rubber gaskets, or gaps between the frame and wall.
  • Run water along the edge to pinpoint leaks if necessary.

📌 For double-glazed units, fogging between panes usually means the unit has failed—resealing the frame won’t fix that.

Step 2: Remove Old Sealant or Gasket

  • Use a utility knife to cut away cracked or damaged caulking around the frame.
  • If there’s a rubber glazing gasket, remove it carefully for replacement.
  • Clean the surface thoroughly to ensure proper adhesion of new materials.

Step 3: Prepare the Area

  • Wipe the frame and edge of the glass with a damp cloth.
  • Let it dry completely before applying new sealant or gaskets.
  • You can apply masking tape to guide cleaner sealant lines.

Step 4: Apply New Sealant

  • Load silicone sealant into a caulking gun.
  • Apply a continuous bead along the joint where the frame meets the wall or glass.
  • Smooth the bead with your finger or a sealant tool for a neat finish.

✅ Use weatherproof, UV-resistant silicone for best results.

Step 5: Replace the Gasket (if needed)

If the original glazing rubber was brittle or missing:

  • Buy a new gasket matching your frame profile.
  • Push it into the frame channel firmly around the glass.

Step 6: Allow to Cure

Let the sealant cure as per the product instructions—usually 24 hours. Avoid opening the window or exposing it to moisture during this time.

Pro Tips for a Long-Lasting Reseal

  • Only reseal on dry days with moderate temperatures
  • Don’t apply sealant over damp or dirty surfaces
  • Match sealant colour to your frame for a professional finish
  • Replace both sides (interior and exterior) if needed

When Resealing Isn’t Enough

Resealing won’t work if:

  • The IGU (insulated glass unit) has failed (moisture between panes)
  • The window frame is warped or water-damaged
  • Structural leaks are coming from above the window (e.g. from roof or gutter issues)

👉 In these cases, consult a professional glass replacement or window repair service.

 

mala mogodu