How to Flash an Exterior Door
Flashing is a very important feature for an exterior door because it prevents water from seeping beneath the door, which could cause mildew or mold to build up on the insides walls of the house. Flashing is something that you can easily install on the door yourself.
- Use a utility knife to cut the wrap, which is located at the header of the doorway. It should be cut at a 45-degree angle at each of the corners. Doing this will create a flap.
- Use some scotch tape to hold the flap up against the door to keep it out of the way while you take measurements for the flashing.
- Use a tape measure to measure the bottom opening of the door.
- Use a pair of tin snips to cut the flashing to fit the opening under the door.
- Put a thick line of silicone caulk on the sill of the door.
- Put the flashing down over the caulk.
- Place the door inside the doorway and measure the side doorjambs. You will need to add 3-inches to the measurement.
- Use the utility knife to cut two pieces of flashing to fit the measurement.
- Apply a line of caulking on the right side of the doorjamb approximately 1-inch below the sill.
- Lay the flashing down over the caulking with the bottom of the flashing resting approximately 1-inch below the bottom of the sill. Continue on to do the left side in the same manner.
- Use the tape measure to measure the door header. You will need to add an additional 4-inches to the measurement.
- Cut a piece of flashing to fit the measurement.
- Place a line of caulking approximately 2-inches to the left of the header and place the flashing on top.
- Remove the tape from the flap and allow it to drop down over the drip edge.
- Apply a line of caulking around all four sides of the flashing where it comes in contact with the wrap.