SCARBOROUGH — The Dunstan School Restaurant, which served buffet-style, modestly priced meals for nearly 30 years in its namesake former schoolhouse, is being sold to an out-of-state grocer that plans to convert the building into a high-end food store.

The sale is expected to be complete by Dec. 12, according to Abel Schultze, who owns the Exeter, New Hampshire-based grocery store, On the Vine Marketplace, with his wife and a childhood friend. A post on the restaurant’s Facebook page confirmed that the building is under contract.

Schultze on Tuesday would not disclose the purchase price, but the schoolhouse had previously been listed for sale at $1.6 million.

If the purchase is successful, Schultze said he expects to begin renovation immediately and open the market’s doors in April 2015.

Dunstan School Restaurant served its last meals in October, after opening in 1985. On Nov. 19, much of its equipment had been scheduled for auction, but the date has been pushed back, according to the auctioneer’s website.

Generations of Scarborough elementary students attended class in the two-story schoolhouse, built at 591 U.S. Route 1 around 1940 and closed 40 years later.

On the Vine’s Exeter store, opened in 2006, sells locally farmed produce, made-from-scratch baked goods, premium-grade meat, fresh seafood, prepared meals and more. Schultze feels the schoolhouse’s 13,500-square-foot space is ideal for a second grocery store.

“I just love the building,” he said, noting that construction of the store would preserve the structure’s red brick exterior and large windows. “It will maintain its character.”

Scarborough is an attractive community for expansion because of its fast-growing population and healthy business environment, he added. Ultimately, he said, he hopes to operate as many as five stores in New England.

The new store will be about the same size as On the Vine’s Exeter location, he said. But unlike that one-floor market, the Scarborough store will include space on the second floor. Much of the cooking will be performed in the building’s basement.

When fully staffed, the new store will employ 35-60 people, Schultze said, about the same number as the Exeter branch. He expects prices to be competitive with those of large supermarkets, or even lower for some items, such as fruits and vegetables.

The product mix will be similar to the New Hampshire store’s, and will be sourced locally where possible, he added.

“We’re always looking for new, local vendors,” he said. “We’re huge on local.”