- 1). Remove the trim around the inside and outside of your window. Pry it from the walls with a pry bar, doing so carefully so as not to damage the wall or the trim. You will want to reuse the trim after the new window is installed.
- 2). Slice away any old, dry bits of caulking from the window frame opening with the utility knife. Also remove any insulation from around the window with the putty knife. Save the insulation so you can reinsert it when your new window is installed.
- 3). Remove the existing window; lift it out of the window frame opening with the help of a friend. Clean away old bits of mortar, caulk or debris with a whisk broom, putty knife and utility knife.
- 4). Caulk around the window opening with the caulking gun and exterior caulk.
- 5). Have your friend help you insert the new window. Place the level against the lower edge of the window and insert the wood shims to raise it in places where it sits lower to make the window level.
- 6). Nail the galvanized nails with the nail gun through the flange in the new window into the window frame.
- 7). Apply another bead of exterior caulk with the caulking gun around the outside of the window to fill any gaps between the window and the frame. Spray aerosol urethane insulation into any other gaps or spaces.
- 8). Replace the exterior trim around the new window by applying exterior caulk with the caulking gun to the back of the trim pieces and piecing them together as they were seated on the old window. Nail the trim to the window frame with the nail gun and galvanized nails.
- 9). Work from the inside of the new window. Cut off any pieces of wood shim that protrudes on the inside with the utility knife.
- 10
Put the insulation you took out from the old window into any spaces or gaps around the inside of the window. Use the putty knife to push it into the spaces. - 11
Replace the interior trim. Apply caulk with the caulking gun to the back of the trim and piece it together like a window frame. Hammer finishing nails into the trim and window frame. - 12
Apply wood putty to the nail heads on the inside and outside with the putty knife, sand when dry with the sand paper. Prime and paint the exterior trim with the paintbrush and exterior paint, and the interior trim with the interior primer and paint.
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