Q: One of our co-op owners has sent the board, through a lawyer, a laundry list of items she wants fixed in our building and is refusing to pay maintenance until all items are addressed. What is her — and the board’s — legal responsibility?

A: To properly determine the legal responsibilities of the parties, it is important to know what items are not being repaired, said Lior Aldad, a Manhattan co-op lawyer, and how extreme the conditions are. Are they within the apartment or in the common area? Do they constitute a violation of the warranty of habitability? Do any of the conditions constitute an emergency by which someone could get injured?

Moreover, Mr. Aldad said, the co-op’s bylaws and proprietary lease should be reviewed to determine who is actually responsible for such repairs. For example, some co-op rules state that the repair of the windows in the apartments is the responsibility of the shareholders, while others make such repairs the responsibility of the corporation.

Because a typical proprietary lease provides that a shareholder cannot withhold maintenance for any reason, if a shareholder fails to pay maintenance when it is due, the board of directors can bring a legal proceeding to collect the money owed. Of course, the shareholder can claim that the warranty of habitability has been breached, or that he or she has been constructively evicted from the apartment. But if the shareholder lost in court, the loss could be very costly. The shareholder would be liable for any unpaid maintenance and penalties; also, most proprietary leases provide for the recovery of the co-op’s legal fees, court fees and related expenses.

“Since at times the value of the co-op’s legal fees and expenses to litigate the issues may be substantially greater than the value of the required repairs,” Mr. Aldad said, “it may be prudent for the shareholder to minimize her exposure by resolving her differences with the co-operative board amicably or in a fashion other than by withholding the maintenance.”