Today's strip isn't literally true, but it's figuratively true. Unless you're talking about the fact that Grab's house is being tore up from the floor up - that's definitely true. It's also true that from the very second you get inside the walls of an old house, every sin of its manufacture is laid bare. And not just in the ways we mention in the last couple panels - all manner of Dad Sins eventually become somebody else's problem, some ancient wickedness to inherit. I can give an example of something that happened to me personally, and it didn't result in any significant cost or danger, which makes it a rarity in this kind of tale. We had to get in the basement walls of our house once, and if we hadn't, we would never have known that the house was made almost entirely of fence posts. I remember thinking, "It's weird to see a fencepost inside."