Daniel Maurer Plywood came down at Mary Help of Christians last week.

It’s official: the owner of Steiner Studios has purchased the East 12th Street lot that includes Mary Help of Christians Church for $41 million. Douglas C. Steiner told The Local he was planning a residential project that would include some affordable housing units.

The deal was closed Friday, according to John Matcovich, the parish manager of Immaculate Conception, where Mary Help of Christians parishioners were relocated in September. “The keys were relinquished,” he revealed to The Local, confirming that Mr. Steiner purchased a lot that includes the church, the school building at 436 East 12th Street, the rectory at 440 East 12th Street, and the parking lot at 181 Avenue A that was formerly home to the flea market.

In September, The Local pointed to evidence that Mr. Steiner was the potential buyer. In State Supreme Court documents filed that month, the archdiocese was authorized to sell the property to 181 Avenue A LLC for $41 million.

Mr. Steiner has now told The Local he plans to build “an 80/20 residential project that includes affordable housing and is contextually appropriate for the neighborhood.” Under the state’s 80/20 Housing Program, developers receive tax-exempt financing if they agree to make 20 percent of their units affordable to households earning 50 percent or less of an area’s median income.

In July, The Times reported that the developer’s firm, Steiner NYC, was “in the midst of closing on its first Manhattan site, land south of 23rd Street where it will build a 100-unit luxury rental building.” The firm has specialized in industrial properties, suburban office parks and multifamily residential properties such as a building in Williamsburg, Brooklyn that was purchased in June for $38 million, a 60-unit rental property in Carroll Gardens purchased for $24.5 million, and “The Hub,” a 720-unit building set for downtown Brooklyn. Mr. Steiner also owns Steiner Studios, a massive movie and television lot at the Brooklyn Navy Yard.

Mary Help of Christians was hit with an evacuation order in September when the neighboring P.S. 60 building was found to be in danger of collapse. But in the past week there have been signs of activity: last week, workers took down construction plywood that had obscured the church. One parishioner spotted construction workers on the rectory’s roof, and said she had heard that soil and water tests were being performed in the adjacent parking lot. And today, individuals were seen going into and out of the church’s former rectory.

It’s uncertain whether the buildings next to the parking lot will be demolished or merely refurbished.