Metal & Dust

I think this song is about a relationship that started off all lovey-dovey because they were in a honeymoon stage and really lusted after on another. However, Hannah is saying that in order for them to build their trust, they need that beginning "love and lust" to begin building that foundation. But, comparing the foundation of a relationship to the literal foundation of a house, ("And when your house begins to rust, all is just metal and dust"), she means that once the house begins to pick at itself, and begins to disintegrate, that their relationship is resolved to two insoluble solids that can no longer mix or mesh together as one.

Then, I believe the chorus is more of a conversation between the two people in the relationship. "We argue, we don't fight" -- It's like she's trying to downsize the argument/fight they're having, that it isn't classified to be so bad as a "fight," but rather an "argument". Then, "stay awake til the middle of the night" just straight forward implies that they're up until the middle of the night "arguing."

Then, the second person comes in to say "We don't argue" as to protest and say "this isn't an argument-- this is a fight. And it is a big stress on the relationship."

A home is a state of mind, a house is a building. They both crumble to dust without the proper care and maintenance.