You are not entitled to any compensation for the work or money you put into the home unless there was an agreement with your roommate--preferably a written one, since proving the existence and terms of an oral agreement, as well as enforcing it, can be difficult--that you would be paid or reimbursed for these things. Without such an agreement, you gratuitously (or voluntarily or freely) chose to improve a home in which you were living (and thereby benefiting from any improvements), and there is no compensation for gratuitous expenditures of effort or money.