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How to Fix a Leaky Window

What is Causing Your Leaky Window?

There are many different culprits behind window leaks. Finding the source of this problem and making necessary repairs is important. This prevents exterior damage to the home, as well as, potential interior damage. Here, our window experts share how to fix a leaky window and address three potential causes of window leaks.

Re-Glazing Windows

  1. Use a putty knife to scrape and chip away existing window glazing without removing the important triangle points.
  2. Use your sandpaper, preferably 120-grit to sand the window frame thoroughly, wiping away excess debris with a rag.
  3. With your hands moving back-and-forth form a roll with the glazing compound until you have a rope design.
  4. Place the rope along the perimeter of the window frame and then push it into place.
  5. Create a flat surface with your putty knife at a 45-degree angle, going from one corner of the window to the next.
  6. Repeat this same process with the other three sides of the window frame.
  7. After the putty is allowed to harden, you should coat it with oil-based wood primer, let it dry, and paint the appropriate color.

Re-Caulking Windows

  1. Remove or peel any loose caulking debris and wash the window and clean any grease that could prevent your caulk from adhering properly.
  2. On a dry day with a moderate temperature, use waterproof caulking as you learn how to fix a leaky window with metal or vinyl details.
  3. Cut the caulking tube at a 45-degree angle with your utility knife and puncture the tip with a 16-d nail and position it into the caulking gun.
  4. Apply a continuous bead of the caulk along the joint in between the window and its frame.
  5. Run your fingers along the bead to ensure that there are no bubbles in the application.
  6. Repeat this same process on the other three sides of the window.
  7. Allow the caulk to completely dry overnight before trying to paint it.

Repairing Window Frames

  1. Try to pinpoint the source of the leak in order to make structural frame repairs to the window.
  2. Get an assistant to spray the window so you observe how the leaks trail inside.
  3. Observe if the trail travels along the wood as it enters, causing potential drywall problems.
  4. Use your pry bar to remove the trim from the leaking area to see in between the window and frame area, to determine if caulking will help.
  5. Remove any existing rotten wood with your putty knife, and then repair the void with an epoxy wood filler product.
  6. Replace any rotten trim and carefully nail it back to the frame of the window.
  7. Apply waterproof caulk to each individual edge, allow this to dry completely, and then repaint the window frame.

Tools & Materials

  • Putty product
  • Putty knife
  • Sandpaper and rag
  • Glazing compound
  • Oil-based wood primer
  • Window frame paint
  • Caulking product
  • Caulking gun
  • 16-d nails
  • Detergent solution
  • Utility knife
  • Pry bar
  • Epoxy wood filler
  • Hammer

If your leaky windows are old, damaged or you cannot repair them, contact PJ Fitzpatrick. We can help you to choose new windows that will seal your home and prevent leak damage throughout the year.

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