missed this post somehow
the 8 1/2 foot is the width of the closet/landing that is there now, and it is indeed only 2 foot deep
the beam i am referring to, if we stick with our deck analogy, would be long horizontal section of the deck frame
(sorry, im not a carpenter, and some of this makes sense in my head, but i dont know how to say it in a way that makes sense to a carpenter)