There are a lot of steps when installing an exterior window. As a Home Improvement Expert, I know that well. That’s why I’ve created a walkthrough to help you on your next window installation project.
Step 1: Prepare the House Wrap
It’s important to note that before you begin your installation, you should read the instructions that came with your window. They often differ slightly between manufacturers.
Once you’ve read through your instructions, take a look at your window opening. If you still haven’t cut the house wrap away from the opening, cut the wrap in an “I” pattern. Make sure the top and bottom are flush with the sill, and then cut a slit down the center of the house wrap. Finally, pull the wrap on the sides around the frame, staple it into place, and trim off the excess.
Step 2: Measure Your Opening
Measure the opening first, then measure your window. Your opening should be between half-inch and 1 inch larger than your window.
Really important note: Make sure the bottom window sill has a downward slope toward the outside for drainage.
Step 3: Apply Protecto Wrap
Apply Protecto Wrap to the sill, making the wrap even with the inside edge and overlapping on both sides by 6 to 8 inches. Once you’ve ensured that the corners are square, cut a slit in the Protecto Wrap to fold it over the edges. Be sure to put a square of the wrap in the corner, and finish it off by overlapping the pieces. Fold the top over the bottom for better protection from water runoff.
After you’ve properly folded and installed the Protecto Wrap, put shims in the bottom corners of the opening and dry-fit the window to make sure it fits. Adjust the shims if necessary, and use a level to ensure the window is level.
Step 4: Caulk the Opening
Use 100% silicone caulk, and make sure you get it underneath the flange. Squeeze a bead all around the top and sides within a half-inch of the opening, but do not caulk the bottom.
Step 5: Place the Window
Now move the window back in place for installation. Add a corner nail and check that it’s level. Secure it with a few more nails, verify that the window is square, and hammer in the nails around the rest of the window.
Test the window to make sure it’s working properly. If it’s not opening smoothly, you can make adjustments with shims around the side.
Step 6: Seal in the Window
Measure and cut strips of Protecto Wrap to place around the outside of the window. The wrap should measure 4 inches longer on each side of the window. You’ll need two strips for each side of the window, and one for the top. Now, measure the window top, so you can cut the flashing to match. Cut it with tin snips.
Apply the Protecto Wrap on each side of the window, and make it flush with the edges while covering the nails. Smooth it in place to make sure the adhesive is fully sealed.
Install the flashing on top of the window, nailing it in place. Apply a strip of Protecto Wrap on top of the flashing, and use it to cover the other pieces on both ends.
Lastly, pull down the house wrap, that you tucked up earlier over the Protecto Wrap, and tape it into place, making sure to seal any openings in the wrap.