An office-to-lab conversion paid off for Rockwood Capital at Waltham Place, a two-building complex at 266-275 Second Ave. that it acquired in May 2013 for $34.5 million.

San Francisco-based Rockwood sold the properties Thursday to life science developer Alexandria Real Estate Equities for $70.9 million, or $352 per square foot.

Operator Griffith Properties of Boston converted half of the 96,695-square-foot building at 266 Second Ave. into lab space and leased all of the available space in less than a year, Managing Principal Marci Griffith Loeber said. The property hit 100 percent occupancy in May.

Completed in 2000, 275 Second Ave. contains 104,870 square feet of office space and a parking ratio of 3.6 spaces per 1,000 square feet. The property is currently 45 percent leased, said JLL Managing Director Frank Petz, who represented the sellers along with Managing Director Jessica Hughes.

Alexandria plans to convert the vacant two top floors of 275 Second Ave. into lab space for occupancy in the first half of 2018, said Thomas Andrews, the company’s regional market director for Greater Boston. The bottom two floors are leased to office users Osprey Software and Symetra Life Insurance Co.

The Waltham submarket is an emerging life science industry cluster, Petz noted, with Biogen hemophilia spinoff Bioverativ headquartered at Alexandria’s 225 Second Ave. and Sanofi operating a drug discovery center at 153 Second Ave.

Alexandria also has a 40,000-square-foot building site at 231 Second Ave. that it’s weighing for a speculative lab project, Andrews said.

As of the end of 2016, Pasadena, California-based Alexandria Real Estate Equities owned 6.3 million square feet of office and lab space in Cambridge, Boston’s Longwood Medical Area and the Route 128 market.

Greater Boston has the largest concentration of life science researchers in the U.S. for the seventh straight year, according to JLL’s Life Sciences Outlook report released this month. Average salaries for researchers have risen 19.2 percent in the past five years to $135,000, while rents in East Cambridge now average $75.05 per square foot.

Core suburbs have benefited from Cambridge’s industry dominance, the JLL report noted. The core suburban lab market – including Bedford, Lexington, Waltham and Watertown – has experienced significant growth with triple-net rents hitting $42.65 per square foot in the first quarter, up 21 percent year-over-year. JLL is tracking 31 lab requirements totaling 1.4 million square feet in the suburbs.

Alexandria Adds To Suburban Lab Portfolio With $70.9M Deal

by Steve Adams time to read: 1 min