How to Repair a Rotted Groove Seal on a Door Frame

Open your door.

Grasp the top edge of the inverted V-shaped exposed portion of weatherstripping set into the groove -- called the kerf -- around the doorjamb, just inside the door stop, on the latch side of the jamb. If you can't work your fingertip inside the notch of the "V," use a pair of needle-nose pliers to get a grip on the weatherstripping.

Pull down and out on the weatherstripping until the fin that fits into the kerf pulls free. Sometimes there's light resistance from the raised lip at the end of the fin that fits into the kerf to hold the strip in place. Adhesive is not used on this type of weatherstrip, so it should pull right out.

Repeat with the strip on the hinge side of the door, then on the header. Retain one side piece as well as the old header piece.

Lay the old weatherstripping out on a flat work surface and use it as a template for cutting the replacement weatherstripping. Cut two side pieces and one header with a utility knife.

Stand inside the threshold of the door. Turn the weatherstripping so the arms of the "V" are up toward the top of the doorjamb. Press the fin all the way into the channel.

Repeat with the weather strip on the latch and the hinge sides of the door -- the "V" should always face into the door frame.

Cut the corners with a utility knife if there is any overlap. Trim at a 45-degree angle, or flat, so the ends of the two side pieces butt up against the top piece.