What you need to do first is get the old garage system away. The garage door can be hung on rails that will allow you to easily build your new. Find the opening and measure what dimensions you’d like. Take measurements of the door from the outside, but don’t make measurements from the inside. Garage doors are constructed to accommodate the current opening. After taking these measurements, you are able to choose the garage door you like and then get it installed. jiq8di7ibk.