Why is my childhood home frequently the backdrop for my dreams? It’s driving me crazy. I’m sure all of the rooms have been featured, including basement and garage. Light up your cigars and unfold your Freudian couch!
Because it is part of who you are.
That’s deep. I think my mind has been blown on the first session.
I’ll attempt at a vaguely serious answer. (IANAP. IANAO. Take with a grain of salt.)
Because memories of that setting are very well-established for you, having been absorbed during a period when you formed memories most easily and strongly, it’s one of the easiest places for your brain to reconstruct as a setting for a dream. Other locations with similarly strong, repeated associations, like your workplace or school, probably also feature often. When the location isn’t particularly important to the dream, you’ll probably get some familiar place. It’s like using stock photos as filler.
It’s likely that some distortions are present, however, even if you don’t recognize them in the dream. (Missing or extra rooms, exaggerated dimensions, and so forth.)
Obviously you want to have sex with your childhood home. You sicko! 
I have a similar thing going on.
My parents moved to a new house years ago. But whenever they figure in my dreams, they still live in their old house, the one where I grew up. For the longest time, I would be really annoyed at them about this, inside the dream: “You have a new house! It’s much nicer! Why are you still living in the old one?” Then they would respond as if they didn’t understand the problem. “Well, we know, but it’s force of habit. Stop complaining about it.”
It’s the weirdest thing. I haven’t had a dream like that in while, though. I mean, where I’m actually upset about them living in the wrong house. They still do it, whenever I dream about them. but it no longer seems to bother dream-me so much. Now they’re just sort of there, and it’s fine.
I’ve never had a dream that was set in their new house. That would be my Inception-style totem, to see whether I was dreaming or awake: I’d check which house my parents were living in.
