Repair the screen for a sliding door by replacing the screen mesh. The task requires a spline installation tool, available at most hardware and home improvement stores, a piece of screen mesh at least 2 inches wider and longer than the door opening, rubber spline and a utility knife.
Remove the screen from the track by lifting so the rollers are clear of the bottom track. Push the bottom of the screen out, and lower it to remove it from the top track. Clean the tracks, and inspect the rollers to ensure smooth operation. If necessary, replace the rollers.
Locate the end of the spline, the rubber tubing that holds the screen in place. Use an awl or another sharp instrument to lift the end out of the channel along the edge of the screen until you are able to grasp it with your fingers. Pull the spline up to remove it, and release the screen.
Center the new screen mesh over the door. Use the convex end of the spline tool to press the screen into the channel. Use the convex roller on the spline tool to press the spline into place. Once the spline is in place and the screen is tight without wrinkles, use a utility knife to cut the excess mesh from the screen, and install it in the sliding door.