How to Replace Windows in Cinder Blocks
- 1). Measure across the width and height of the opening with the old window still in place. Order the window unit based on those measurements. Don't remove the old window until the new unit arrives.
- 2). Remove the trim border from around the interior edge of the window opening, using the hammer and pry bar. Don't break the trim; leave it intact as you take it off. Set it aside.
- 3). Set the new window unit into the window opening, bottom first. Push the top side up and back so it butts against border of the trim on the outside edge of the window, inside the external cinder blocks.
- 4). Put a level on the window. Insert shims along the bottom and sides of the window unit until it reads level and plumb. Secure it with mounting screws driven outward through the sides of the unit, through the screw holes. The screws should grab into the wood frame that's just inside the cinder block exterior.
- 5). Fill the spaces around the perimeter of the unit with foam insulation, spraying it into the spaces.
- 6). Put the trim back in around the interior edge of the unit, using your hammer and finish nails. The trim should cover the spaces around the edges of the window unit.
- 7). Caulk the joints where the trim meets the wall and window unit.
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