In Brussels, student houses are usually large-ish buildings (tall and narrow with a few rooms on each floor) which have been converted into flats, each room self-contained: kitchenette, shower, desk, bed. There are no communal areas. You don't share a house, you rent a room. So of course houses are mixed - you can see very little of those in the other flats, just like in any appartment block! In my case, one of my IFES team-mates was in a room in the same building as me. But the buildings look like the non-flat converted family houses next to them.
Now that my team mate Barnaby and I have both moved from Brussels to our respective places in England, it transpired that this produced the following confusion for the children of our team leaders:
Parent: We're going to visit Rosemary.
4 yr old son: And Barnaby.
Parent: No, Barnaby's in his house, we're just going to Rosemary's house.
Son: But they live in the same house!
Parent: No... [suspecting what the reasoning was] they aren't married!
Son: Why not?
It never crossed our minds, as all Belgians know how it works with such student buildings... but it wasn't so obvious for a 4 yr old and 2 yr old. D'oh.