Removing Old Windows

• Remove the trim around the original window with a pry bar and hammer without damaging it. Remove the glass and mark a cutting line 2 inches away from the outline of the window on the outside with a compass and a pencil. Use a 3 1/2 inch circular saw to cut through the siding but not the framing surrounding the window.
  
  Use a pry bar to take off the strips of siding that you cut. Use the nail puller part of a hammer to remove the nails from the flange. Take out the old window frame and remove the 2 by 4 that is under the window frame.
  
  

Preparing the New Window

• Use a measuring tape to measure the window to find out what adjustments need to be made for both the length and the width. Break the wallboard and the interior of the window to give the extra height. Reveal the corner bead, which is a metal strip found at the corner, by using the pry bar. Be careful not to damage the interior wall while doing this.
  
  Use the pry bar to tap against the corner bead to make a small crack on the interior wall in that area. Use a utility knife to make the crack deeper. Tap out the nail heads with the pry bar from the outside of the window. Take away the nails then the corner bead. Place lumber in the places that are too wide and use nails to keep them in place.
  
  

Installing the Window

• Bend the nailing flanges on the window at right angles and apply caulking on the center of each one. Place the bottom of the window in the sill carefully and tip the window up, with the flanges in position. Level the window and use a shim to adjust spacing if needed. Use a hammer to secure galvanized roofing nails into the flange. They must also go through the framing. Use a nail gun on the nails if the hammer cannot fit.
  
  Cover the gaps at the corners with self-adhesive rubber corner seals. Insert roofing paper with a putty knife around the whole outline of the window. Fill the outside gaps with caulking. Attach narrow pieces of lumber around the window with nails to make it flush with the house. Put the house trim back up with nails, matching the ends together. Apply caulking around the trim and smooth it down and into the grooves. Put up jamb extensions and interior molding with a pin nailer.