All those construction cranes and concrete trucks throughout the Washington area are not a mirage. The F. W. Dodge Division of McGraw-Hill Information Systems reports that total building contracts in the Washington area totaled $3.971 billion in the first nine months of this year, up 5 percent from $3.778 billion a year ago. Residential construction contracts totaled $2.081 billion; nonresidential work, $1.889 billion.

The Springhill Lakes Apartments, Prince George's County's largest apartment complex, is putting on a new face and promoting its public image, with a $12.5 million renovation of its Greenbelt apartments, charity drives and the formation of a scholarship fund for high school graduates.

Lerner Corp., which owns the complex, Landover Mall and the new Greenbelt Hilton, believes that "it is important for business, in light of the economic development in the county, to be active in supporting social and educational programs in this area," said Kimberly Andreadis, Springhill Lakes' new marketing director.

The renovation, which Andreadis said will not result in rent increases, includes the installation of new carpets and kitchens in the complex's 2,899 apartments for Springhill Lake's 9,000 residents, who make up almost half of Greenbelt's total population. Additional parking lots, access roads and improved landscaping also are planned for the 154-acre complex.

As part of its community outreach efforts, Springhill Lakes will let community and social service groups use its community center. The staff also plans to help with charity drives, such as one planned this month to help fight cystic fibrosis, Andreadis said.

Also, a $4,000 scholarship for Prince George's Community College in Largo will be awarded annually to a graduating senior from Greenbelt's Eleanor Roosevelt High School, she said.

Construction began this week on a controversial, $1.2 million extension of Montrose Road in Montgomery County from Seven Locks Road to Falls Road.

Robert C. Merryman, county chief of transportation engineering, said that the 5,200-foot, two-lane extension will provide direct access for Potomac commuters south of I-270 while "eliminating cut-through traffic from residential streets," particularly within the Montgomery Square and Potomac Woods subdivisions.

Some residents of the subdivisions, however, have opposed the extension, contending, among other things, that it would pose a threat to their long-established residential neighborhoods.

The extension, which is called for in the Potomac master development plan and which has been listed in the county's capital improvements budget since 1980, should be completed by December 1986, Merryman said.

The City of Alexandria has $338,000 available in below-market, fixed-rate mortgages for purchase of homes in the Potomac East and Potomac West neighborhoods near the Potomac River. The mortgage funds will be available at a 9.53 percent interest rate until next August.

The funds are provided by the Virginia Housing Development Authority under recent bond issues. Borrowers must meet eligibility requirements established by the state agency, and the loans generally are for first-time homeowners or for persons who have not owned a home in the last three years.

Call 548-4366 for more information.

IN THE BUSINESS . . . The Virginia Association of Realtors reported 5,268 homes sold in September, an 18 percent increase over September 1984. Sales for the first three quarters of 1985 are up 12.4 percent over the January-September period of a year ago . . . The Park Terrace Hotel has reopened at 1515 Rhode Island Ave. NW on Scott Circle after $17 million worth of renovations. The eight-story building has 189 rooms . . . Construction has started on the Monroe Business Center, a seven-building office complex in Herndon, with $20.95 million in construction financing provided by Abacus Real Estate Finance Group. The complex will include four one-story buildings and three three-story buildings . . . Sales of public real estate securities reached a record $3.3 billion in the third quarter for the third straight quarter of record sales, according to the Questor Strategic Real Estate Letter . . . The National Association of Realtors' Housing Affordability Index rose to 98.1 in September, its highest level in 6 1/2 years. The September index figure meant that a family earning the median gross annual income of $27,563 that month had 98.1 percent of the income needed to qualify for a $60,240 mortgage covering 80 percent of the median existing-home sales price of $75,300 . . . The International Council of Shopping Centers, the trade association for the industry, has started a campaign to fingerprint millions of children ages 3 to 14 during the week of April 7 to 13.

PERSONNEL FILE . . . The Virginia Association of Realtors has named David G. McWatters, a sales associate for Long & Foster's Sterling office, as "Salesperson of the Year" . . . Arlington broker Michael C. Fox was recognized as "certified residential broker of the year 1985" by the Virginia association at its Acapulco convention . . . The Business and Professional Women's Club in Maryland has named Long & Foster as "Employer of the Year," an award recognizing local businesses that are responsive to women workers . . . Financial Service Group Inc. has named Jay A. Zawatsky president of its syndication subsidiary, Financial Service Equities Inc. . . . Jerry Catron has been appointed vice president and Virginia division manager for Capital Homes . . . Lawrence D. Friedman has been named vice president and senior associate claims counsel for Ticor Title Insurance Co.