I have a recurrent dream similar to that!
In the dream, my house always has several large, empty, almost forgotten/unknown areas waiting to be reconditioned and become available for use.
Since we own an old house that's
not big enough for everybody and everything....this recurring dream always seems pretty exciting and positive while dreaming (though I never seem to do anything with the space, just look at it and marvel over the possibilities) but rather sad when I wake up and realize I actually don't have a whole extra floor or wing waiting for development.
I always kind of figured it was a reflection on some feelings of unused personal potential?????