Total construction volume is expected to dip 5 percent in 1979, but inflation will boost its value about 2 percent above this year's level, according to the annual McGraw-Hill/Dodge forecast. The building boom of 1978, which approached record levels, is over, according to the forecase, yet it will not be followed by a bust next year.

George A. Christie, Vice president and chief economist of the firm, which is considered an authority in construction activity, presented the findings at a recent conference here. This year had a lot in common with 1973, he observed: It has been second only to 1973's record construction levels, double-digit inflation in construction and permanent financing, and some shortages of materials.

However, 1979 is not expected to parallel 1974, when construction suffered its strongest post-war decline. The big differences are there is no glut of unsold housing, there is little consumer resistance to high prices, and there continues to be a steady, if diminised, supply of mortgage money, Christie said. Total construction value next year is projected at $155.8 billion.

In Washington area, the National Association of Home Builders predicts that 17,000 housing units will be started next year, compared with 21,149 that were to have been started this year.

This past year, when about 2 million units of housing were started nationally, marked the end of the three-year-boom cycle, but not the beginning of a bust, in Christie's opinion.

The Savings and Loan League this week revised its forecast of housing starts next year, reducing anticipated home production by 100,000 houses, from 1.75 million to 1.65 million. The shortage of mortgage money and a reduction in demand for new houses because of a slowdown in the economy were cited.

Single-family housing starts between now and spring will decline to 1.1 million, at an annual rate, but then gradually recover to a 1.25 million annual rate by year end, for a total fo 1.175 million units for the year, Christie predicted.