The Tillerman kids come from the sea and return to the sea. They’ve grown up in a cabin beside the ocean in Provincetown, MA, and they relocate to Gram’s old farmhouse on the Chesapeake Bay. Dicey seems to like it because it's near the water, with its "little waves and long tides" (Introduction.5), but the town of Crisfield itself is probably not as quiet as she'd like.
Nevertheless, it's got good people. Dicey and her siblings are able to make some friends and create their own small community, all of which begins at their home—Gram's house.
Gram’s farmhouse is old and battered, but it's just what they need. Sure, it may have this whole shabby chic vibe, thanks to Gram's continuing poverty, but to Dicey, it’s practically a wonderland: "Home: a home with plenty of room for the four children in the shabby farmhouse, room inside, room outside, and the kind of room within Gram too […] the kind of room that was what they really needed" (Introduction.3).
What really matters here are not the details of the run-down house, but the qualities of the people who live there. Gram’s heart is as expansive as the house, and that’s all the Tillerman kiddos really need.
The barn behind Gram’s house contains the sailboat, which makes it pretty much Dicey’s temple. She’s painting the outbuilding in the first chapter, as a way of both earning her keep and creating a shrine to her boat. : "…the barn was completely painted, top to bottom, all four sides, patched and painted and looking good" (1.2). Sprucing up the barn is a way for Dicey to put her stamp on her new home.
But the barn isn't the only place at Gram's that catches the Tillerman kids' eyes. The younger kids sneak up there one day when Dicey’s not looking, and she confronts James about it:
"I thought we lived here," James complained.
"We do," Dicey said. "but—" (4.20-21)
But what? It seems to Shmoop that Dicey still feels like they’re guests in Gram’s house, and that's why she's all for not going into the attic. And of course all that attic-is-forbidden stuff lets us know that this attic is probably a pretty important spot.
So at the end of the book, when Gram (now officially their guardian) suggests the boys go up to the attic and bring down the photo albums, the moment carries a ton of weight: the house is finally just as much theirs as it is hers, and they’re free to settle into all the rooms.