Step-by-Step Flashing Replacement on Windows

Replacing window flashing is a simple process. Peel-and-stick window flashing makes the installation of new window flashing easy and effective. Each window should take about two hours to re-flash and seal against water and other elements. Properly installed window flashing can lower heating and cooling bills and prevent the replacement of the wood surrounding windows due to water damage.

• 1

  Remove the window from the hole in the wall using a crow bar and screwdriver. Remove all old window flashing with your hands or a flathead screwdriver. Wear work gloves to protect your hands.

• 2

  Cut a strip of window flashing slightly longer than the base of the window frame. Make sure the flashing piece is wide enough to fit over the sill, jamb and horn of the bottom of the window.

• 3

  Stick the flashing over the bottom frame of the window so that it covers the window horn, sill and jamb.

• 4

  Fill in any gaps along the window frame with spray-foam insulation. Fill in the empty weight pocket with foam insulation, as well.

• 5

  Cut two strips of window flashing membrane slightly longer than the length of the window. Peel the backing off of the flashing and stick it along the sides of the window frame.

• 6

  Add small patches of flashing to the area of the window frame where the two pieces of flashing meet for extra insulation.

• 7

  Cut a piece of flashing slightly longer than the top of the window frame and stick in into place. Patch the corners of the window near the top just like you did with the bottom.

• 8

  Install the window over the flashing normally, starting with the interior portion of the window and adding the exterior portion second.

• 9

  Push a line of foam backer rod between the outside frame of the window and the window itself.

• 10

  Add another layer of flashing membrane outside the exterior edge of the window frame. This helps insulate the foam backer rod. Caulk the edges between the flashing and the window frame inside and outside the frame.

• 11

  Install the interior trim of the window inside the house with nails to hide the interior flashing membrane.