WATERTOWN, MASS. — Locally based developer Berkeley Investments will undertake a project to convert a building at 64 Pleasant St. in the western Boston suburb of Watertown into a 105,000-square-foot life sciences facility. The two-story building offers a conference room, rooftop deck, fitness center and outdoor gathering spaces. Berkeley will upgrade the property’s utility and mechanical systems, elevate the ceiling heights, introduce reinforced concrete floors and add lab space. SGA is the project architect. The development team hopes to complete core and shell construction by the end of next year. Newmark has been tapped to market the building for lease.