How to Install a Drip Edge Over a Slider & Molding

Existing Door with Horizontal Siding

• 1

  Measure the top of the door opening. Purchase a drip cap in a length that extends at least one inch longer on each side of your molding or door opening. If you can't find a section in a standard measurement, cut the drip cap to fit with the razor knife.

• 2

  Remove the molding and bottom section of siding above the door opening.

• 3

  Cut and fit a section of vapor barrier such as Tyvek or other self-stick moisture block to the exposed wall above the doorway. A height of four to six inches is best if you have this much of the wall exposed.

• 4

  Put the molding back in place over the door. Apply a line of caulk above the molding where the drip cap will be placed. Run it along the edge where the casing (molding) will meet the drip cap.

• 5

  Slide the drip cap into place on top of the molding, and apply another line of caulk where the edge of the drip cap meets the vapor barrier material.

• 6

  Replace the siding section you removed above the drip cap.

Existing Door with Vertical Sheet Siding

• 7

  Measure and purchase your drip cap to fit the doorway. Remove the molding from above the door.

• 8

  Cut and apply a piece of the self-stick moisture barrier where the wall is exposed and as far up under the siding above where the molding was placed as you can get it.

• 9

  Re-attach the molding above the door, and run a line of caulk in the seam between the molding and siding.

• 10

  Slide the drip cap edge up under the siding until the bottom edge rests in place on top of the molding. The drip cap should not be screwed in place; the wet caulk and the siding should hold it in place. Holes in the drip cap from fasteners would allow moisture to seep into the wall.