Many people think repairing window screens is a very tough job. But replacing a damaged screen can be done with just a few minutes and a few simple tools.
You just need a utility knife, a pair of pliers, and a spline roller, which you can find at the home center for less than 10 bucks.
First, remove the old screen by pulling out the spline, which is like a piece of rubber rope. Then spread out a roll of new screen material over the frame, and cut it to overlap all sides by an inch or so. Then use the spline roller to force the old spline back into the track to lock the screen in place.
Finally, when the spline is all in, you can trim off the excess screen with a utility knife and you’re done.