Repairing Sagging Screens
The key to keeping your new screen from sagging or drooping
It's not much of a stretch to get a drum-tight, wrinkle-free screening when replacing the screen panel on a door. After removing the old screen, lay the door frame on a flat work surface and slip a 1x4 block under each end. Clamp down the middle of the door to put a slight bow in the frame.
Next, attach the screen to one end of the frame with staples or rubber spline. Move to the other end, pull the screen snug and flat — but not too tight — and fasten it. Then release the clamps; the door frame will pull the screen tight as it straightens. Finish by securing the screen sides to the frame.