21. Adjustments can be made with shims, which should be installed at all anchor points and anywhere necessary to keep the unit correctly in place.
22. To check for square, measure both window diagonals from corner to corner to make sure they match.
23. Insert all installation screws that were included with the new window.
24. Seal all joints on the interior and exterior with caulk/sealant.
25. Insulate gaps between the window and frame that exceed 1/8 inch. If using spray foam, select a low-foaming product designated for “windows and doors” that won’t flex the window material, which could prevent proper operation.