Retrofit Window Replacement Instructions
- 1). Take the height and width measurements of the window opening from inside the perimeter where the sashes sit. Move the sashes up and down as necessary so you can take the measurements from the jamb, the inner part of the opening.
- 2). Subtract 1/2 inch from both of the measurements. Order your replacement window using the adjustment measurements. Don't take out the old window until the new one is on site and you've measured it to ensure it's the correct size.
- 3). Pry off the trim from the interior edge of the opening with your flat bar and hammer. Don't break the trim. Set it aside so you can reinstall it later. Remove the sashes.
- 4). Set a strip of fiberglass insulation on the bottom edge of the opening in the wall. Set the bottom of the replacement window unit on top of the insulation.
- 5). Push the window up and into the hole, putting more insulation in around the sides as you go. Stop when the window rests against the perimeter of trim around the exterior side of the opening.
- 6). Hold a level across the top of the window unit. Slide shims under the bottom and along the sides of the unit until the bubble is in the center of the level. Secure the window in place when it's level. Drive 3-inch screws through the screw holes at the sides of the unit, and into the framing of the window opening.
- 7). Put the trim back in place, using a trim nail gun. Spread beads of caulk with your caulk gun all along the joints where the window unit meets the trim.
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