Mia's house might not be in the middle of the street, but it sure is her castle. Listen to how she describes it:
The house is almost like a living creature that keeps expanding and contracting and remaking itself. Every inch of it was built by my father and grandfather from all different kinds of wood—whatever they could borrow, barter, or beg for. They could never agree on how the house should be laid out, so they each did their own thing and eventually met up in the middle. (1.29)
Whoa. We want to go there. But more importantly, we can tell that Mia's family is eccentric and free spirited just from her description of the house. Who else would live in a multi-layered cavern filled with secret tunnels and stairways to nowhere? A quirky bunch, that's who. Like, say, a family with three children, one of whom sees colors when she hears sounds, another who prefers to forage her food in the woods, and another who believes in pretty much every superstition known to man.
The house is a symbol of the family's perseverance and strength, too. Everyone in town thinks it's a big eye sore, but the Winchells love it there. They built it themselves, and Mia's dad keeps adding to it long after it should be done. You know, kind of like how they stick together no matter how baffled they might be by Mia's synesthesia.