How To Replace a Window Screen
Window screens are easily damaged and they wear out over time. The screening material in most windows screens is easily replaced. It is usually cheaper and easier to just rescreen a window screen frame rather than to replace the entire frame.
Window screens made since roughly the 1950's on use a simple technique to hold the screen in place inside the frame. The metal frame has a narrow channel that runs around the entire perimeter. The screen material is placed over the channel and a spline (a round rubber or vinyl tube-like material) is forced into the channel, pulling the screen in with it and locking it in place.
To rescreen a window you will need some new screening material, either aluminum or fiberglass, rubber spline sized to fit your frame and razor knife and a spline roller.
Start by removing the spline material. Check the corners, find the end of the spline and pull it up with the tip of your razor knife. Pull the spline out of the channel around the entire frame and then pull out the old mesh screen.
At this stage, some people prefer to measure and cut a piece of replacement screen. I prefer to cut the screen only after I've installed it. The advantage is no risk of cutting the piece too small and simplifies holding the material in place while it is secured. When you install the spline, it pulls and shifts the material; having an oversized piece simplifies installation.
Lie the screen material over the frame, overlapping the channel by about 1/4 inch. Start at a corner and work along the longer side. Press the spline into the channel with just finger pressure; working along the length of the frame. Keep an eye ahead of the spline to make sure the screen isn't shifting out of place and adjust as necessary.
If you make a mistake or are unhappy with the results, simply pull up the spline and redo the section.
Press the spline into place, don't use the spline roller yet unless the spline keeps coming out. Once the spline is in position, secure it by running over it with the spline roller. If you are using aluminum screen, go over the spline in stages, don't try to force it into place in one pass.
As you get to the third and fourth sides, the tension of the spline should pull the screen tight, however, pull all slack away from the middle or the screen will be loose or have ripples in it.
Once you roll in the spline all the way around, cut it and tuck in the end.
Using a razor knife (or metal shears for aluminum screen), cut the screen along the spline. Cut from the center of the frame toward the outer edge to ensure that you don't accidentally cut your new screen. That's it.