When building a 2nd building of the same type, does the 2nd building take up a building space? The rule states:"... placing it on top of the other building leaving the top of the bottom card exposed." This would seem to imply that it doesn't take up a second building space, but doesn't seem logical.
(Mike) Up to 2 copies of a building can occupy the same location per the rule you quote. The theme is that you are doubling the size of the building and what it can do for you. Think of it as a major renovation that enhances the capacity of the original building vs. building a separate building. Page 18 and 19 of the rulebook detail the benefit of doubling a building in the description of each building.