The Weissberg Corp. has topped out its five-story building at 2500 Wilson Blvd. in Arlington. The building, which will contain 100,000 square feet of office space, is 55 percent preleased to NBI Inc. of Boulder, Colo., an office-automation company. It will be ready for occupancy in August.

The building will have a domed three-story atrium with balconies. The first floor is designated for retail use. The building was designed by Smallwood, Reynolds, Stewart & Associates.

Other recent developments in commercial realty in the Washington metropolitan area:

*ERC International, a defense contractor, leased 110,000 square feet at Flint Hill Office Park, Fairfax. The 10-year lease has an aggregate value of $26 million. The location will be the company's corporate headquarters.

*The Department of the Army's Baltimore Distribution Corps of Engineers leased 69,000 square feet from Dickinson-Heffner Inc. at Airport Square, 856 Elkridge Landing Rd., Linthicum.

*Karl Corby of Corby-Linn Realty purchased the 60,000-square-foot South Potomac Professional Center, 9401 Indian Head Hwy., Oxon Hill, from the National Development Council. The purchase price was not disclosed.

*Westinghouse has leased 57,000 square feet from Dickinson-Heffner Inc. in the Airport Square Tech Park II Building, 900 International Dr., Linthicum.