The number of building contracts in Salt Lake, Davis and Weber counties in the first four months of 1988 declined 11 percent from the same period a year ago, according to the F.W. Dodge Division of McGraw-Hill Information Systems Co.

George A. Christie, vice president and chief economist of Dodge, said building contracts in the four-month period decreased to $206.5 million from $232.7 million a year ago. Nonresidential building contracts increased 12 percent from $98.8 million to $110.7 million this year and residential building contracts dropped 28 percent from $133.8 million to $95.8 million.Nonresidential buildings include commercial, manufacturing, educational, religious, administrative, recreational and other buildings not designed for shelter while residential buildings include houses, apartments, motels, dormitories and other buildings designed for shelter.

During April, total building contracts in the three counties decreased 40 percent from $84.3 million a year ago to $50.4 million this year. Nonresidential building contracts dropped 49 percent from $37 million to $18.8 million and residential building contracts declined 33 percent from $47.3 million to $31.5 million.