How to Properly Install Flashing on an Exterior Door Frame

Flashing Tape

• 1

  Measure the bottom of the door frame and add 12 inches to the length. The extra 12 inches is added because you will run the tape up the bottom six inches of the side jambs.

• 2

  Cut a strip of flashing tape to fit your dimensions.

• 3

  Place the edge of the flashing tape on one side jamb six inches from the bottom. Position the tape so that you can cover the front edge of the door frame with one inch of tape.

• 4

  Press the tape firmly against the side of the door frame, working down toward the sill plate. When you reach the corner where the side jamb and sill plate meet, cut a tab an inch wide in the tape.

• 5

  Press the tape firmly into the corner and across the sill plate. Cut a tab into the tape when you reach the other corner, then finish running the tape up the other side jamb.

• 6

  Apply a second strip of flashing tape on the frame, positioning it so that it overlaps the edge of the first piece by an inch. Do not cut the tabs in the second strip of tape as they are unnecessary because this strip is not covering the front edge of the door frame.

Metal Flashing Strips

• 7

  Measure the bottom of the door frame.

• 8

  Cut a piece of flashing to fit the sill plate.

• 9

  Place the flashing against the front edge of the sill plate, then fold it over on top of the plate.

• 10

  Nail the flashing to the sill plate with galvanized roofing nails. Use two nails at each end of the sill plate and every six inches in between.