How to Re-caulk Sliding Doors

  • 1-3 hours
  • Beginner
  • 25-75
What You'll Need
Putty knife
Steel wool
Caulking rope
Damp, clean rag

Given enough time, you may need to re-caulk your glass patio door. An effective caulking is the only way you can keep moisture and extreme temperatures outside while you enjoy your outdoor view.

Step 1 – Prepare your Glass Door

Before beginning to re-caulk your door, you'll need to identify leaking areas in it and the frame. Unless you want to caulk the entire door and frame, you can make your job easier if you re-caulk only the edges that are leaking. In order to determine which of the edges leak, you'll need to clean the glass, especially around the door's perimeter. Use either a commercial glass cleaner or a solution made of warm water with a few drops of detergent added. If you encounter spots that are difficult to remove with your glass cleaner, you can try a fine grade of steel wool, which should do the job without scratching the door glass or the metal frame. (Test in an inconspicuous spot first.)

Step 2 – Check the Door's Operation

There is little point in re-caulking a door or frame that you actually need to replace. If the door fails to operate normally, determine whether you'll be able to repair the door or if you should replace it. If you need to repair it, complete the repairs before you re-caulk. Moving the door may cause minor damage to any caulking.

Step 3 – Remove Damaged or Loose Caulking

Inspect the entire edge of the frame to determine which of its edges will need re-caulking. Using a putty knife, remove the old or damaged caulking between the house siding and the sliding door frame. If you find leaking or deteriorating caulking on any of the four sides of the frame, you'll need to remove all of the caulking on that side of the frame. Also check for and remove any damaged or loose caulking on the glass pane. Where the rubber seal is still tight and seems watertight, you will not need to replace it.

Step 4 – Apply Caulking Rope and Caulk

In spaces in the frame where you removed old caulking, fill them with caulking rope that has been rated for doors and windows. Insert the caulk nozzle into a corner of the frame and fill gaps with the caulk; you want to create a single, continuous bead of caulk until you've reached the opposite corner. Re-caulk the glass, if needed.

You should use a product that matches the existing caulk. If you are unable to buy a matching product, consider replacing the entire portion of older caulking.