Considering you're on the xbox you're not going to find very much clay for brick houses in the current version. The xbox runs on version 1.6.6 which has very little clay. It only spawns with the same x and z coordinates or something like that. The only option to get a lot of now for a brick house would be either through modding it in and/or duplicating it. If you want to stay legit then wait for an update.