Mary Margaret McMurray was almost 6 years old when she and her sister arrived at the orphanage after their parents died of influenza in 1917. She stayed until she graduated from high school and took a job as a secretary at an insurance company.

“The convent was so big,” said Ms. McMurray, now 97 and living in Queens with her daughter, herself a Sister of Mercy. “And there were so many children there. I had a lot of company. But it was very pleasant.”

The nuns taught her a lot, she said, and not all the lessons were found in books. “They taught me to be a positive person,” she said. “And of course, religion, too.”

Changes in social welfare policies in the 1970s led the order to open group homes, encourage adoption or foster care, and expand services to the homeless and developmentally disabled. Fewer women were entering the order, while the remaining sisters grew older. The convent became their retirement home, including one floor devoted to the infirm. The neighborhood around them changed, too, attracting Latino, black and Hasidic families.

The order’s leadership realized in the last few years that the old building presented too many obstacles for older women. An engineering study in February recommended extensive exterior renovations, removal of asbestos and rebuilding the foundation. Sister Christine McCann, the president for the region that includes the convent, said the millions of dollars needed for repairs could be better used to finance social and educational work by the order, which still has about 4,000 nuns in the United States.

Selling the convent could help raise even more money for their mission, Sister McCann said, but no decision has been reached. Though the building is not a landmark  giving wide leeway for any new owners to develop or demolish the property  some nuns said they hoped they could still return to the chapel on special occasions.

Since September, with the help of two sisters with nursing backgrounds, the 38 nuns who lived at the convent have been presented with options for new homes  from apartments in assisted-living centers to nursing homes run by religious orders.