Unless you have a written agreement stating that your work on the house would be performed in exchange for rent, you have practically no legal redress available.
Did you and the house owner agree that your work would be at an hourly rate of "X" dollars per hour, to be converted to the amount of the monthly rent, and that your work would substitute for cash?
Did anyone witness the verbal arrangements between yourself and the house owner with regard to your working on the house in exchange for rent?
Did the owner ever state to you that if you did not or could not move in, he/she would pay you the cash equivalent of what you would possibly be owed for the work performed?
Either way...even if you have a written document guaranteeing that you would be paid an hourly rate for the work you did...you would still have to hire a lawyer and take the house owner to court. If you won your case, the judge might also award you attorney's fees as part of the settlement, but it's highly likely that HALF the cost of an attorney would be less than what you would be owed for the work you did. Most attorneys won't touch a case like that.