There are two basic kinds of windows found in a stucco home; the first with nailing flanges underneath the stucco, and the second with exterior trim around the glass portion of the window. The removal process for each one is very different, since a window with exterior trim requires a simple disassembly, while a widow set directly in stucco requires specialty tools and professional repair after a new window is set.
Remove the window trim from the interior and the exterior of a window that has visible trim. Use the flat end of a nail bar to loosen the trim evenly and gently pry it off. Remove nails from the flange with the nail bar on the exterior and the interior of the window and carefully slide it out.
Measure 2 inches out from each corner of a window set directly in stucco. Removing one of these windows is time consuming and creates an opening in the stucco that a knowledgeable stucco professional can later patch.
Hold a straight edge or pop a chalk line evenly along the 2-inch border on each side. This distance should put you directly over the nailing flange, covered by the stucco.
Use a skill saw, fitted with a diamond blade to cut along all four edge lines. Take care not to cut past the corners. Set your blade depth to ½ an inch. If you don’t think you’re hitting the metal mesh beneath, set it another ¼ of an inch deeper. Stop cutting when your saw blade reaches the corner.
Place the chisel in the corner area and use the hammer to pound it into the chalk line. This is a slow process and it’s more important to take care and keep from chipping the stucco on the outside of the line than it is to pound away and finish the job quickly. As you chip, clear away any pieces that come loose.
Pry the inside stucco away from the wall in the direction of the window. Use your chisel or flat bar to ease the hardened masonry away from the lath beneath. The wire mesh should come away, too. If not, you’ll have to snip the mesh with wire cutters to remove it.
Pull the nails from the nailing flange fastened into the boxing. Do this on the interior of the window also. Many stucco homes have interior window trim, which makes it much easier to remove. If not, you’ll have to use the same measuring and cutting process on the inside of the window.
Pry the window carefully from the hole. Small bits of stucco may stick and you may have to scrape them away with your chisel.