fraternity housing

How does the Fraternity housing work, so far ive noticed that only one fraternity has an on campus house, either way as a transfer an issue i could potentially have is not getting any on campus housing (limited space) if fraternity's do not provide housing how would that work, its seems to defeat the whole purpose of a fraternity if they cant live together. Also, how open are fraternity s to juniors joining (im a sophomore now and plan to transfer for fall 2016) Any help on any of the questions would be great or if there is an official that would know these answers a link of contact info would be greatly appreciated