We’re going to install a flanged window unit, using DuPont™ FlexWrap and Flashing
Tape. The first step in cutting a window opening is to make an I-cut. And I start by making
a level head cut at the rough opening, finding the center, making a vertical cut all the
way down to the sill and then finishing the I-cut with a level cut at the sill. Fold the
flaps around on the inside, tack them into place with a hammer tacker, now cut the excess
material off then we’ll have the HomeWrap cut and folded back. After folding the jambs
back in, I’ll cut a head flap, make a 45 degree angle cut on either side then I’ll
tape it temporarily out of the way with a few pieces of contractor’s tape. The next
step is to apply the FlexWrap sill using six inch FlexWrap - peel off the release paper.
Eyeball the ends level so it will be centered in the opening, keep it flush with the back
inside of the rough opening. Take a J-roller to get even pressure in the jambs and the
sill, make sure it is good and tight in the corners. From the inside of the building I’ll
flex the sill piece out on either corner, fold it down over the sill piece, apply pressure
with a J-roller to get good contact. The next step is to caulk the back side of the window
flanges, we use DuPont™ Residential Sealant and I’ll caulk the window head and I’ll
caulk the jambs but I’m going to leave the bottom sill flange uncaulked to provide a
weep area for moisture to find its way out. I’ll plumb and level the window and fasten
it in place with screws. After the window is installed I’ll take a piece of DuPont™
Flashing Tape, pull back some of the release paper and start at the head. Work my way down
the window opening, covering the window flange. I’m going to apply the window head flashing,
this is DuPont™ Flashing Tape. I’ll use a J-roller to roll, apply pressure, get good
contact. Then I’ll take the HomeWrap flap that I cut earlier and fold it down, I’ll
tape the corners. And with the last piece, tape the window flap head flap down to the
bottom. And after the window is completely installed and flashed, we’ll come back and
apply DuPont™ Window and Door Foam. It is a low expanding foam and we’ll apply it
just in the cavity to seal the head and the jamb.