How to Install Picture Windows
October 11, 2010
1. Remove the old window carefully without damaging the opening or surrounding areas. Make sure the opening is free of left-over hardware from the old window and clear away any loose particles.
2. Put the new window into the opening provisionally to make sure it will fit without any further cutting or scraping. Remove it, and make any necessary adjustments.
3. Install flashing tape covering inside the rough opening. Add more in the upper corners to prevent future leaks. Apply caulking in two rows all around the opening to get a good seal.
4. Put the window assembly back in and use your leveling tool along with shims to get the frame absolutely level.
5. Screw or nail the assembly temporarily in place followed by further leveling, adjusting, or adding shims. Once it's perfectly level and plumb, affix screws or nails permanently. Add flashing tape to cover the entire nail fin.
6. Stuff all surrounding gaps with fiberglass insulation to assure energy efficiency.
7. Reattach any interior trim. Do the same outside replacing any displaced siding and finish up with carefully-applied caulking compound to make a solid seal around the window.
It looks easy on paper but things crop up along the way. You should have a kit from your dealer with more detailed instructions plus someone to help with the heavy stuff and hopefully expert advice. Additionally, Internet videos on YouTube offer good window installation advice.