GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Audio Play Icon Headphones Icon Plus Icon Minus Icon Check Icon Print Icon Picture icon Single Arrow Icon Double Arrow Icon Hamburger Icon TV Icon Close Icon Sorted Hamburger/Search Icon

Extra Protection for Head Flashing on Windows and Doors


1. Self-Draining Sill Pans

2. Sill Pan Flashing Options

3. Sill Pan with Regular Peel-and-Stick

4. Sill Pan with Flexible Peel-and-Stick

5. Flashing Flanged Window Jambs

6. Flashing Pre-Cased Jambs

7. Head Flashing Windows/Doors

8. Counter-Flashing the Head

Air-Sealing Inspection of a Window

Durable Window Installation

A Home Energy Audit

Most Recent Videos

Job Site Visits

Green Home Tours

Get the Most from GBA

Video Transcript:

If you don’t have a Z-flash lap that you can lap a piece of housewrap under to get a mechanical lap flashing over the top edge of the flashing tape for the head of the window, what you can do is put a piece of aluminum or other metal flashing that’s grooved into the foam itself. What I like to do is take a piece of metal flashing about 4 to 6 inches wide and just bend a 45-degree angle in it about 1/2- to 3/4-inch deep. Then use that metal as a straightedge to guide the knife blade. Now, these knives work a little better than an ordinary utility knife because you can extend it a little bit further and get a nice, steep angle on it. You only want to go about a third to halfway through the thickness of the foam; you don’t want to cut all the way through the foam. And that groove is not quite wide enough to fit my flashing up into. So I use a little flat bar that just opens that groove up enough so I can slip the metal in there. It may take a couple of passes to open the groove up. A few pieces of housewrap tape will hold that in place. Water that does get down into this foam sheathing gets drained onto the flashing, onto the head flashing of the window, and…

One Comment

  1. Dirk Gently | | #1

    several years ago I worked a
    several years ago I worked a icf project and had to scramble to find details like noted here. I used this same method for a many doors/windows. There were many stick framed dormers on the house, I had to flash a 40' section like detailed here.Instead of utility knife I used my small battery circular saw to cut the kerf in the foam and it was much quicker. I backed up the kerf cut with silicone caulk as well.

Log in or become a member to post a comment.



Recent Questions and Replies

  • |
  • |
  • |
  • |