Fiberglass screens can cut down on the amount of UV rays and sunlight and are great for protecting furniture or wall-to-wall carpet. Fiberglass screen material is the most commonly used screening as it is easy to use and is the least expensive of all window screen mesh. This material can be very long lasting. How to Replace a Screen in a Door or Window Frame 1. Cut the Replacement Material to Size Once you've removed the screen frame from the window, lay the frame on a flat surface and roll out enough replacement screen that it covers the entire frame. 2. Remove the Old Screen Use a nail-punch or other sharp object to loosen the end of the spline and pull it up from the channel and out of the frame. The screen should come out easily once you've removed the spline. 3. Lay the New Screen Across the Frame When laying the new screen over the frame, lay it out with the curved or concave side down. This will make it easier to install the screen and ensure that the new piece lies flat in the frame. You can then use clamps to hold the screen taut onto the frame while you work. 4. Replace the Spline It's advisable in most cases to replace the spline along with the screen material. Once you've creased the screen all the way around the frame, begin placing the spline in the channel. Start on one side and use your fingers to push the spline into the channel from one side of the screen to the other. 5. Press the Spline into the Frame Unspool a length of spline and install it by pressing it into the frame's groove using a rolling spline-tool. Gently pull the spline tight with one hand as you carefully press it into the groove with the roller. 6. Cut Away the Excess Trim the spline to length using a utility knife. Also use the utility knife to trim off the excess screen mesh from the outside of the frame.