Your sliding patio door gives you a great view outside, but one flying baseball or an aimless bird can shatter the glass. If you have broken patio door glass, you don't have to replace the whole door. It is simple to replace the glass yourself with some tools, and you save yourself the trouble of buying a new door. Here are some tips to replace broken sliding patio door glass.

Prepare to Work

For this project, you need:

• work gloves and safety glasses
• broom
• vacuum
• newspapers
• bread slices
• putty knife
• hammer
• pry bar
• tape measure
• straight edge
• permanent marker
• caulk
• glass cutter
• replacement glass 

Spread newspaper by the work area. Remove large pieces of glass by hand, and set them on the paper. For carpeted areas, pick up tiny pieces with a vacuum.

Sweep glass from concrete or wooden floors. If tiny bits of glass remain, pick them up with the bread slice. The glass will adhere to the bread's soft surface.

Since smaller glass bits can be hard to spot, run the bread over the area in an expanding circle, and press firmly. Discard bread slices and newspapers in a cardboard box to place in the trash, and run the broom or vacuum over the areas once more to ensure no glass remains.

Remove the Old Glass

Wearing work gloves and safety glasses, insert a putty knife between the window trim and door. Use the pry bar to hammer to loosen it from the glass, taking care not to damage trim or nails, because you will reinstall the trim later. Pull remaining nails with the pry bar.

Remove the glass from the door, and scrape remaining glass still lodged in the original caulk with the putty knife. Take measurements of the door height and width for replacement glass, and subtract ¼ of an inch from each measurement. Have it delivered to you, because the glass likely won't fit in your vehicle.

Install the New Glass

Check your glass to make sure the edges are straight. If the edges aren't straight, lay the glass on a flat work surface. Use the marker and straight edge to mark the measurements needed to make the edges even. Cut across the markings, but avoid deep cuts so you won't damage the glass. 

Inspect the glass again to ensure the edges are straight. Caulk around the edges, and insert the glass into the opening. Add another thin layer of caulk to secure the glass against the trim. Reinstall the trim, and scrape excess caulk with the putty knife.

Replacing glass in a sliding patio door is easier than replacing the whole door. If the door or door glass is seriously damaged, however, you may need a full door installation.