These days, the
screening material that is used in windows and doors is some sort of plastic or
fiberglass mesh. This has removed the problem that older galvanized screening
had of rusting with age. Eventually the plastic will begin to break down due to
exposure to ultraviolet rays from the sun and will need to be replaced.
The screen mesh is stretched over the aluminum frame and held in place, as you
describe, by a vinyl strip that is forced into a slot in the frame. Just find
the end of this strip and carefully pull it out. If it appears brittle or has
little flexibility, it should be replaced along with the screening.
Buy some screen that is slightly larger than the frame and some of the gasket
strip that is long enough to go all the way around. You will want a nice flat
place to lay the screen down, and possibly clamp it in place, checking to be
sure that it is nice and square. Lay the screen over the frame with the mesh
lining up straight with the frame. Start in one corner and carefully press the
vinyl bead into the slot until you reach the next corner.
If you can recruit a couple of spare hands, have them pull the screen snuggly
toward the side opposite the first side while you pull it toward the second
side. Work slowly and carefully, keeping the mesh fibers in line with the
frame. The key to a good final product is to keep the screen taught but not
over-stretched while you lock it in place with the vinyl bead.
Once you get all the way around, cut off the bead and tuck in the end. Using a
sharp razor knife, trim away the excess screening material. Be careful not to
cut the frame, the screen that will remain, or your fingers.