The Christmas stockings of area home builders are bulging this year, thanks to the hot pace of new construction and sales.

Buyers have reappeared in the marketplace. And if forecasts for 1978 are accurate, those 1977 home buyers will be able to move into the new year with the satisfaction of having acted before prices - and mortgage rates - moved even higher.

This year will be remembered for its record number of single-family house starts and sales, a torrid market in which the Washington metropolitan area shared. In review:

Both new and resale houses moved well in almost all sections of this area. They sold despite record prices levels that would have been jeered as "unreal and out of sight" two years ago. Today the new, $80,000 house is commonplace and houses priced at more than $100,000 are not unusual.

Town houses, cluster houses and condominium apartments have established a strong beachhead in the market because they represent virtually the only opportunity for first-time buyers to deal with the economics of home ownership under the $60,000 level.As a result, many young people and even some mature empty-nesters are making a choice on the basis of what is affordable and available.

As a result, apartment sales have been strong at Watergate at Landmark, Skyline City at bailey's Crossroads and the Rotonda near Tysons Corner; the selling pace of rehabitated apartments and town houses at Fairlington Villages attracted national attention.

Resale houses continue to be potent force in this market because many buyers are taking a new view toward the housing stock. Both young and older buyers are opting for settled neighborhoods, taller trees and closer-in locations. Where they find plastered walls, they revel in the luxury of acquiring a construction feature difficult to locate in houses costing $150,000 and up today.

While there's no denying that subdivision development has spread beyond Frederick and Annapolis, Md., and Frederick and Centrecille, Va., there also must be recognition of an increasing trend to in-town living. That includes parts of the District of Columbia, as well as urbanized areas of Alexandria, Arlington, Takoma Park and Chevy Chase. There seems to be a nice balance between rehabilitation and new construction.

A trend to condominium conversion of both garden and high-rise apartments has picked up steam in varied areas, but especially in the District, which has continued to embrace rent controls. Sales have been strong in a broad range of prices.

Meanwhile, the new towns of Columbia, Reston and St. Charles and the massive Montgomery Village development have shared in the general upturn. Their development continues to hinge on a relationship to Washington, but more and more they are creating their own sense of place - not unlike booming Annapolis or awakening Leesburg, Va.

In addition to residential construction, this area has witnessed a boom in office building construction, along with commercial and industrial development. Downtown office leasing has continued to attract attorneys, associations and accountants - everyone who wants to hang a shingle in the center of the action. But Tysons Corner, Crystal City and the planned Pentagon City also are strong on office buildings. And a new complex of low-rise prestige office buildings in a park-like setting is under way in the big Hamlets' rental apartment complex in western Alexandria.

Although the level of a new rental apartment construction was relatively soft in 1975 and 1976, the total increased sharply, to an estimated 7,350 new units in 1977. The 1978 outlook is slightly higher. Most of these new rental dwellings are federally subsidized.

Increasingly, this nation continues to move strongly into owner-occupied home ownership. Single-family houses, town houses and condominium apartments are being bought by investors who rent them out. The availability of mortgage money and relatively attractive interest rates induced considerable home buying in 1977.

The National Association of Realtors has pointed out that the 55 million single houses across the land now have an aggregate value in the almost incomprehensible neighborhood of $2 trillion. Additionally, the association pointed out that one-third of those houses are owned free and clear while the mortgaged properties have an average debt of less than 40 percent of value. That's mainly because values have been going up strongly while most mortgage balances decline every year, even as new high-rate mortgages are created.

The real estate segment of the economy performed in muscular fashion this year. Home building bounced back; new construction projects, both actual and projected, rebounded; leasing was strong. Commercial brokers made some big deals and mortgage bankers made major commitments. Architects rebuilt staffs depleted by the miseries of 1974 and 1975.

John M. McGinty, of Houston, the outgoing president of the American Institute of Architects, put the state of construction in perspective when he observed, "Most of the important problems of today's society - energy, cities, environment - are in our bailiwack . . . The nation needs design solutions."