Over the next five years, the Loudoun County school system will grow by more than 19,200 students and will need 19 more schools in which to educate them, Superintendent Edgar B. Hatrick III told the School Board on Tuesday night.

Hatrick recommended funding five new schools next year alone: three elementary schools that would open in 2007 and a middle school and high school in western Loudoun that would both open in 2008. In addition, he suggested financing renovations at Hillsboro, Rolling Ridge and Sugarland elementary schools next year.

The recommendations are contained in Hatrick's five-year, $833 million Capital Improvements Program. The CIP, which is revised each year, predicts when and where new students will arrive in the county over the next several years and proposes building projects to keep pace.

The School Board will debate and revise the document before voting on it in January. It will then be sent to the Board of Supervisors for approval.

Hatrick said school construction costs have been rising as a result of industry-wide price increases in steel, concrete and other materials.

School Board Chairman John A. Andrews II said he wished the overall cost of the building program were lower, but he said that the numbers were understandable at first glance and that he would study them further.

"I'm frustrated, but I'm not surprised," Andrews said. "It's tough to think we've done all this work. You'd hope the numbers would be lower, but construction costs are going up 20 percent."

At the end of September, 44,011 students were enrolled in county schools, 7.8 percent more than last year but about 700 fewer -- 1.6 percent -- than school planners had predicted. Still, they emphasized that they expect big yearly growth for years to come, meaning that they recommend little slowdown in school construction.

Still, the documents showed delays for several projects from last year's program, including a new Leesburg high school that had been scheduled to open in 2008 and that Hatrick now said should open in 2009. Three elementary schools that school planners felt would be needed in 2007 were pushed back -- one in Leesburg and another in Dulles until 2009, and a third in Brambleton until 2010.

The presentation of the building program is the first step in a months-long budgeting process that School Board members and supervisors are already signaling will include close scrutiny of school expenses.

Concerned that the county has been taking on too much debt for construction projects, the Board of Supervisors said last winter that it would add no more than $100 million in capital projects to each year's budget -- although the board ultimately approved more for last year. Hatrick's recommendations for next year total more than twice that amount -- about $204 million.

The School Board is also engaged in discussions about whether to build larger schools. A committee has recommended increasing the size of high schools to 1,800 students and middle schools to 1,350. Several parents opposed the idea at a public input session this week.

In the absence of official action, this week's planning documents assume that high schools will be built for 1,600 students and middle schools for 1,200, as in past years.

Several board members have said they support larger schools. This week, Priscilla B. Godfrey (Blue Ridge) said she opposed the move, and Sarah B. Smith (Leesburg) said she was leaning against it. If the recommendations are adopted, the CIP must be rewritten to reflect the larger sizes.