How to Replace a Window Without Removing the Frame
- 1). Measure the window opening (with the old windows still in) from side to side and top to bottom, holding the tape measure in the window tracks. Take two or three measurements from different points in both directions, moving the window sash up or down as necessary.
- 2). Take the smallest measurement from the width and the height, and subtract ½ inch from both. Don't remove the old windows until the new ones are delivered.
- 3). Pry out the thin strip of trim that runs along the inside of the window opening, just in front of the window sashes (this isn't the frame that goes around the window, but is just inside the frame). Don't break the trim as you remove it. Pull out the sashes.
- 4). Set a strip of insulation on the window sill. Stand the new window unit on top of it, then push the unit back into the window opening. The trim around the exterior perimeter of the hole will stop the window from falling through.
- 5). Set a level horizontally along the new window unit, and slide shims under it and along the sides until it's level. Secure it by using your drill and screwdriver bit to shoot the long screws that came with the new unit outward through the provided screw holes.
- 6). Put the trim back in place around the interior perimeter of the opening, just behind the frame and in front of the new window. Secure the trim with finish nails and your hammer. Run caulk around the seam where the window meets the trim.
