A critical addition to St. John's Lane Elementary School probably will not be ready in time for classes in September, school officials said last week. The announcement has angered parents who lobbied for the extra space and could force some teachers at the already crowded school to conduct classes in the gymnasium or cafeteria for as long as two months.

At an emergency meeting with parents Friday, Charles Ecker, associate superintendent for finance for the Howard County school system, said the five-classroom addition to the Ellicott City school could be completed four to eight weeks after school begins. The addition is designed to accommodate 125 students.

Sydney Cousin, director of planning and construction for the school system, is more optimistic about the project. He said the construction company originally had one month between the delivery of the module and the start of school to make the necessary electric and plumbing connections. That period has been reduced to one week.

"There's still a good chance that {the unit} will be delivered in time and that the electrical and plumbing connections will be made," he said.

Parents of children who have had to deal with cramped space at the school for two years are irritated by news of the delay.

"We're very frustrated," said Rosemary Slack, president of the school's PTA. "We need this addition. Every room in the school is being used."

The school, which has a capacity of 460, is operating with almost 100 more students than it can hold, and classrooms have been created out of every available space, including a janitor's closet.

Options suggested by school officials -- such as temporarily converting the gym or cafeteria until the addition is available -- are unacceptable to some parents.

"Both places are in use all the time," Slack said. "The food service staff needs the cafeteria in the morning to set up for lunch, and the children need the gym for gym class. Where will they go if the weather's bad?"

Principal Andy Barshinger said the school staff counted on the addition to ease the space problem. "We'll be full with it and very cramped without it," he said. "If the module doesn't arrive on time, we'll have to find space somewhere. We don't know all of the options yet, but we'll choose from the best of a bad bunch."

The project has been plagued with delays since the board accepted the first round of construction bids last September.

The school board expected to award a contract on Oct. 22, but was unable to proceed after all of the bids exceeded the budget. The board then began the process again.

"We've hit roadblocks at every turn on this one," said Patti Veirkant, spokeswoman for the school system.

Originally planned as a permanent brick building, the addition was later changed to the more expensive modular unit after the board decided that the modular building, which can be disassembled and moved, was worth the additional expense. "If populations shift in the future, we can move it to another area," Ecker said.

The school board awarded a $650,000 contract on Jan. 28 to Hankin Construction, a Maryland firm, which hired a company specializing in modular buildings to construct the addition by Aug. 1.

The subcontractor, Cousin said, cannot deliver the addition until Aug. 31, which would give Hankin only one week to install electric and plumbing systems in the building.

Parents said the school system should have seen the crowding problem coming and prepared for it.

"We conducted a survey for the Department of Education last year and found 40 new housing developments that were either finished or under construction in the area," Slack said. "This means an additional 300 children in the area -- enough to fill another elementary school."

Two new elementary schools are scheduled to open in the northern and northeastern districts of the school system in the fall of 1990, but that doesn't appease parents of students at St. John's Lane.

"There've been too many setbacks in this area," Slack said. "It's our children who are going to suffer."