What is the importance of the Halsey Street house in the novel, Halsey Street?

The Halsey Street house is the property Ralph bought after marrying Mirella and where Penelope grew up. The house is in decaying condition and has had a leak on one of the floors for a long time. The garden used to be beautiful when Mirella lived there, but only her flower pots remain. Penelope refuses to return to live in the house when she moves back to Brooklyn. She moves back in when Ralph has to be put in a home, and the house has been signed over to her.