Toswiah/Evie uses the image of floors to ask the reader to imagine what it's like to feel like you're walking on solid ground—and what it feels like when that solid ground starts to shift or disappear. She guides us:
Close your eyes and imagine the floor beneath your feet—cool hardwood maybe. Or softly warm and carpeted. Sit down and lift your feet up off it and imagine you can never put them down on it again. Ever. See how quickly the feeling of that floor fades? See how much you want to feel it again? How lost you feel with no solid place to put your feet? (1.10)
Toswiah/Evie feels like the floor has been ripped out from under her. If you don't have a floor, there's nowhere to walk, so you're stuck in one place. Toswiah/Evie, of course, is moving, but the move causes her to feel stuck emotionally for a long time, unsure of herself and who she is. And the same is true for every member of the family.
She continues, "It's okay to put your feet back down on it. Maybe in your lifetime that floor's not going anywhere" (1.11). We get the sense here that Toswiah/Evie is jealous of the reader's security—or at least the security she imagines the reader has.
Describing her house, she says, "Put your feet down on my old floors in Denver and keep walking" (2.15). The floors provide a way for her to get the reader from place to place, they're her way of inviting us into her life and to follow her on her path.
As Toswiah/Evie is adjusting to her new life and trying to hold onto Toswiah Green, she says, "Curl your toes into the soft pine of your floorboards. And do remember me" (16.80). But this is the last time she talks about floors. It's as if she's decided she can't depend on them for security anymore, and instead must depend on herself. Once she finds her place in her new life, she can let go of the solid image of floors she once depended on. She stands on her own, no matter what's beneath her feet.