Former Matheson home in Key Biscayne sells to owner next door for $5.5M

A waterfront Key Biscayne home once owned by a member of the Matheson family sold for $5.5 million to its next-door neighbor.

Interior of 645 Sunset Circle

County records show John Zelaya, director of Cayman Islands-based Investors Trust Assurance, and his wife Ana Zelaya bought the waterfront Key Biscayne home at 645 Sunset Circle. The Zelayas already own the property next door at 635 Sunset Circle.

A Vero Beach-based trust controlled by Aurelio Fernandez sold the 12,020-square-foot lot, which currently has a three-bedroom, 2,000-square-foot home. It sold for nearly $460 per square foot based on the land. Fortune International Realty’s Brigette de Langeron represented the seller, according to Realtor.com. Great Properties International brought the buyer.

It features a private beach, 180 feet of water frontage and a dock that fits up to an 80-foot yacht. The listing also mentions plans for a new 5,650-square-foot home. Property records show it last sold for $4.8 million in 2011. Before that, the 1970s house was owned by Finlay B. Matheson of the Mathesons, Key Biscayne’s founding family.

The new owners are adding on to their 25,112-square-foot plot next door at 635 Sunset Circle. Their three-story home features three bedrooms and a waterfront pool. In 2007, Zelayas paid $10.9 million for the 9,300-square-foot mansion, which was built in 2000. Altogether, they now own 37,132 contiguous square feet.

In December, Key Biscayne recorded its priciest residential deal ever with the $47 million sale of 775 South Mashta, the former estate of William J. Matheson. The new owner of that property bought the adjacent mansion months later for $12 million.