To replace a damaged door screen, begin by removing your door using an appropriate method and lay it on a flat surface. Then, remove the old screen and replace it with a new one.
With the door laying on a flat surface, examine the edges of the screen where it attaches to the frame to locate the spline, which is a thin flexible strip. Locate one of the cut ends of the spline and insert the end of an awl beneath the edge.
Lift the edge up gently and grasp the spline with your fingers and pull to remove it from the doorframe.
Pull the old screen to remove it from the door before laying the new screen over the entire door. Line up the edge of the replacement screen with the outer edge of the door frame.
Press the screen into the channel in the frame with the convex spline tool, rolling the tool along the perimeter of the door frame channel to slot the screen into place.
Position the spline on top of the screen, and use the concave tool to press it into the channel, rolling the tool to press the spline into the channel. This secures the screen in place.
Trim off the excess screen with a utility knife before screwing the handle and any hinges back onto the door. Screw the hinges back onto the doorframe. If you have a sliding door, set the rollers into the track of the door and push the top section into place.