A 51-year-old, 11-story office building at 1010 Vermont Ave. NW., formerly called the Denrike, has been sold for $7.4 million by a group called 1010 Associates to Blackridge Investment, a Netherlands Antilles corporation. The 66,000-square-foot structure recently was renovated. Hal Boles and Vernon Knarr of Coldwell Banker, who represented buyer and seller, will also take care of leasing and management of the property.

A do-it-yourself home building seminar will be held Oct. 3 and 4 on the Loudoun campus of the Northern Virginia Community College. The cost is $25. Information is available at 323-4551.

H.G. Smithy Co. has arranged financing of $1.6 million with Manufacturers Life Insurance Co. for a recently completed town house office project in the Sugarland Business Park in Herndon. The development has 38,400 square feet of space, 60 percent of it leased.

Architect Robert B. Molseed of Annandale has been elected president of the area chapter of the Construction Specifications Institute, a non-profit technical organization concerned with improved specifications practices in construction.

Brokers Thomas Wartha and James McDavid of RE/MAX Advantage Realty Ltd. in the City of Fairfax, announced plans to open a branch office in Oakton.

Watergate Development Inc. has named Brenneman Associates Inc. sales agent for the 77-unit James Place luxury condominium on 30th Stree NW in the Georgetown waterfront area. The Brenneman firm also is handling sales at the 107-unit condominium conversion being done by Holladay Corp. at 2800 Wisconsin Ave. NW.

James A. Harrison, now serving as president of the Maryland Association of Realtors has been named Realtor of the Year by the Prince George's County Board. He also is a member of the board of directors of the National Association of Realtors. The Montgomery County Board of Realtors named Lowell E. Hendrick Realtor of the Year. Owner of his own brokerage firm in Silver Spring, he has been in real estate for 31 years. o

Dewberry, Nealon & Davis, an engineering and architectural firm based in Northern Virginia, has named Blair Ashworth/McSpadden as assistant to the partnership. She was office administrator there for 15 years. Also, engineers Bernard S. Hyatt Jr. and Lawrence A. Wilkes Annapolis office and Wilkes in Gaithersburg.

The Washington office of the Veterans Administration has named Jack G. Reynolds loan guaranty officer, replacing Robert O'Toole, who was named deputy director of the loan guaranty service of the central office.

Awards will be given to James R. Ingham Jr., Pamela Cox Parkinson, Frank Emmet Jr., James L. Eichberg, J. Fernando Barruetta, Cornelia B. Maury, Peter Rucci, Donald Boucher and Don John Edwards by the Washington Board of Realtors at a dinner-dance Friday at the Mayflower.

Walker & Dunlop has appointed Manfred Duggins, John Hauser and Douglas Wright property managers.