I have a roof pitch that goes from about 3′ to 20′ above my garage, which allows me to stand erect in most of the area. I want to convert this to an attic storage. I have 2 x 8 ceiling joists running the width of a double garage. I would like to be able to put a lot of weight up there without having to worry about it. Would a ceiling support running down the middle of the garage with posts at each end be enough?