Nutritional supplement market Rexall Sundown sold its Boca Raton office building to Butters Construction & Development, which will spend $3.5 million on renovations and upgrades.

The company, a subsidiary of Sundown Naturals in Bohemia, New York, sold the 59,264-square-foot office on 5 acres at 851 N.W. Broken Sound Parkway for $6.125 million to Coconut Creek-based Butters. Rexall Sundown will keep its corporate offices in the building, said Adam Vaisman, director of acquisitions for Butters.

The building has three tenants and is 25 percent occupied. Butters plans to attract more tenants by investing in a renovation plan that’ll include a new entrance canopy, glass door entries, elevator cab renovation, new air conditioning and heating equipment, upgrades to the lobby, new awnings, landscaping and benches, and fresh paint.

“We love the area and frontage we have on Congress [Avenue] as it bodes well for visibility and future leasing opportunities,” Vaisman said. “Leasing is already underway and we will focus on the smaller size tenant in the market. Office rents are rising and we are very bullish on the market as no new office has been built and vacancy is diminishing.”

The office was built in 1987 and last traded for $2.3 million in 1992. It’s in the Park at Broken Sound.

CBRE’s Jeff Kelly represented the seller in the deal.