An Upper East Side condo that displaced a popular Park Avenue preschool in 2013 and had to be scaled down to meet historic district requirements will finally start sales this month.

The condo, 1010 Park Avenue, is an 11-unit offering from the Extell Development Company at East 85th Street, on the site of an annex to the Park Avenue Christian Church, whose small congregation reaped $25 million from the sale, plus two basement levels of new meeting and event space in the new building.

But the deal uprooted a longtime annex tenant, the Park Avenue Christian Church Day School, an upper-crust preschool that had to abruptly relocate to the Upper West Side just as the 2013 school year was to start. At the time, angry parents called Extell to complain, the company’s executives said.

But if disgruntled families are no longer as much of a concern, the condo could face other headwinds.