I discovered that my recurrent dreams of hidden rooms in a house I once lived in are not unique, they have been shared by J-, who lived in the upper duplex at the same time. She brought it up, we had been talking of something completely unrelated. The dreams, at least in outline, were identical. Another floor existed, a third floor which was much more elaborate, filled with furnishings, things left behind by her ex-husband. In my dreams the third floor was filled with things left behind by the former occupants- our landlord- things that were much nicer than his family had in real life.
Another variation that J- and I shared was the sense that the whole neighborhood had undergone gentrification, with chic restaurants and upscale town-homes surrounding our squalid shacks. There was also the sense that something had to be done, that lawyers and the city were trying to seize the property and we were powerless to prevent it.
Once, years ago, my mother was coming out of anesthesia. She kept speaking about "The garage- is it going to be in the right place?" My parents had built a new garage many years prior, it went up without a hitch, but the mild trauma of that experience for her still lived at the top of her subconscious. This sense of place must be important for an organism and surely the relentless change of the modern world must be at least partially responsible for the lack of grounding that so many people experience in their lives.