15. NOT USING AN EXPERT WHEN REPLACING WINDOWS – When you touch the exterior of your home and you replace or remove a window, you are disturbing the home’s building envelope. This is your protective cover to ensure that moisture, wind and rain don’t do damage. You need to work with an expert in this area because even though your windows may look amazing, if they leak you will create a much bigger problem later on. Do it right the first time and don’t be afraid to interview a few specialists to see what their process or method is for making sure your windows are weatherproofed.