Remove all the screws from the underside of the frame of the chair holding the damaged nylon webbing in place. Remove the damaged webbing from the chair. Save the screws for reattaching the new webbing.
Count how many nylon webbing strips go across the chair horizontally. Measure across the seat of the chair for your horizontal strips and add 3 inches. Cut the necessary number of horizontal strips to the required length.
Measure from the top to the bottom of the chair and add 3 inches. Cut the necessary number of vertical strips.
Attach a horizontal strip by folding the end of the strip into a triangle and inserting a screw through the nylon webbing. Screw the end of the webbing to the hole at the underside of the chair from where you removed the damaged webbing. Repeat with the other end of the webbing strip and repeat with all the remaining horizontal webbing strips.
Fold the end of a vertical strip into a triangle and attach it with the screw just like the horizontal strips. Weave the strip under and over all the horizontal strips. Fold the end into a triangle and attach with a screw on the underside of the chair.
Repeat the weaving process, alternating the under and over, until you add all the vertical nylon webbing strips.
Remove all the vinyl webbing strips from your patio chair or just the damaged ones if desired, by unscrewing all the screws from the underside of the frame of the chair. Keep the screws to attach the new vinyl strips.
Measure from one screw hole on the underside of the frame to the other on the opposite side of the chair. Cut the vinyl strips to this measurement. You may want to start with one strip and see if it fits properly first and then make the necessary adjustment on the rest of the strips.
Pre-drill holes in the vinyl webbing by using a 3/16 drill bit to make it easier for you to screw the strips to the chair. Drill the holes 1/2 inch from the end of the strip.
Boil 10 cups of water in a large pot and insert several strips at a time. Let them sit for five minutes to make the strips pliable and easy to work with.
Screw the strips to the chair.