Unscrew the screws located on the bottom of the metal drip edge or rail. Don’t remove the screws.
Pull out the strip located between the door and the drip edge.
Measure the metal drip edge on the shower door to determine the size of rubber sweep you need for your door. You can also measure the existing sweep after you remove it from the bottom of the door.
Cut the new sweep with the utility knife to fit inside the drip edge. The typical size of a sweep measures 36 inches, which you can adjust accordingly with the knife.
Slip the new strip in the opening between the drip edge and the door.
Secure the screws on the drip edge back into place.