Major expansion projects are set to begin at two Irving high schools this month, but cost estimates are running over budget.

MacArthur High School and The Academy of Irving ISD are being expanded to deal with overcrowding. Both schools also are receiving science labs to meet new state graduation requirements.

Estimated costs for the project at MacArthur increased from $11.5 million to $12.9 million, while expected costs for the Academy expansion is up from $15.1 million to $16.6 million. The projects will be paid for from bonds approved by voters in 2001 and November 2007.

Officials say they are examining ways to cut costs.

"We're going to do the best that we can to get the project within budget," said assistant superintendent Scott Layne.

School trustee Randy Stipes said he has some "discomfort" with the projects being over budget.

"My biggest concern is we have a lot of projects ahead, and I don't want people saying we spent all this money up front," Mr. Stipes said. "We don't want to shortchange people at the end."

Much of the cost increase is because administrators added a $1 million cafeteria expansion to the MacArthur High renovation, which was not included in the November bond election. Administrators say the cafeteria is overcrowded and the addition will expand its capacity from 700 to 850 students. The MacArthur expansion also includes a 20-classroom addition and nine science labs.

MacArthur High faces the most severe crowding, with many students attending class in portable buildings that cover the school's tennis courts. About 2,300 students attend MacArthur, which has a capacity of about 2,100, Mr. Layne said.

At The Academy of Irving ISD, new classrooms and lab additions are expected to expand student capacity from 1,400 students to 1,700 students. The additions will consist of four classrooms, three science labs and four specialty labs.

The Academy project will also add a 500-seat auditorium and a gymnasium, which will allow the school to meet state physical education requirements.

Construction at both schools is expected to last through next school year and end sometime in 2009.