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How To Replace Horizontal Sliding Window Glass

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If you have broken slider window glass, either one or both glass panes can break. Sliding windows operate in a horizontal track much like sliding glass doors, and they are commonly have aluminum casements. Broken glass windows should be fixed right away as glass poses a danger, but you don't have to replace the whole window. Here are some tips to replace glass in horizontal sliding windows.

Prepare to Replace Glass

For this project, you need:

  • work gloves
  • safety glasses
  • rags
  • window cleaner
  • masking tape
  • drop cloth
  • broom
  • dust pan
  • rubber mallet
  • tape measure
  • carpenter's level
  • pry bar
  • screwdriver
  • utility knife
  • caulking
  • caulk removal gel
  • wood shims ( thin wood pieces)
  • glazing points 
  • replacement glass

If the glass is just cracked, make an "X" over the glass with masking tape to prevent the pane from shattering when you remove it.  Sweep the larger pieces of glass, and vacuum smaller bits. Lay a drop cloth over the floor to catch glass, and rope off the area.

If the slider is bent, gently tap on it with the hammer to straighten it. Measure the height and width of the window opening, or if possible, measure the old glass.

Remove the Window Frame

Inspect the frame for remaining glass pieces, and gently tap them with a mallet, or pull them loose with a pry bar. Use the screwdriver to loosen the corner screws one at a time holding the frame in place, and put them in a safe spot, because you will reuse them. Slide cracked window glass out of the frame, and discard it. 

On some windows, you may need to remove rubber stoppers. If you can't pry them off by hand, remove them with the pry bar. Check the gasket for damage, and replace it if it is damaged. 

Install the New Glass

Chip existing caulk with the utility knife. Apply the caulk removal gel to caulk that is hard to scrape, let the gel set two -three hours, and try to scrape it again. Clean the inside of the window frame with the rag and window cleaner to remove dirt and caulk remnants. Add a bead of caulk around the window frame, and let it dry.

Replace glazing points and install a new gasket, if necessary. Set the window in the frame, measure it with a carpenter's level to ensure it is even, then press it firmly into the caulk. Insert wood shims in the frame to make the window even, and reattach the frame.

Your window should look as good as new. If you don't trust your skill, or you need windows on an upper level replaced, contact a contractor or click here for more information.