Why is there a limit of how high you can go in housing?

I'm only wondering now as to why this is a thing for housing, in Tel Galen main room, the barrier is about half way up to the ceiling, as for outside.. I'm not to sure exactly how high up you can go but I can tell not to far. If there was no limit, could possibly be creative with building an exterior room on the side of Tel Galen. (I'm only just using Tel Galen as an example)
Other housings such as the Coldharbour Surreal Estate , without the limit, could build a possibly skyscraper.. although I do not know the sky limit on that housing either..
What if there were no sky limit?