Montgomery County school leaders approved a $1.74 billion construction plan Monday night that would add hundreds of classrooms to Maryland’s fastest-growing school system while keeping on schedule some projects that had been slated for delay.

Days after parents clamored for more funding to build and fix county schools, the Board of Education unanimously adopted much of a proposal offered by Superintendent Joshua P. Starr. But the board moved to keep revitalization projects for middle and high schools on track despite Starr’s plan to delay some of them, a change that increases Starr’s $1.55 billion capital improvement program by $192.6 million.

“These projects have been delayed time and time and time again,” said Philip Kauffman (At Large), the board’s vice president. “It’s not that there is ever enough money to do what we need to do.”

The new capital improvement plan seeks to ease overcrowding with five new schools and 22 addition projects over six years. Starr said it does not fully meet the district’s needs — which would cost $2.2 billion — but described it as an ambitious plan nonetheless. Starr had said he was seeking to be fiscally responsible by not proposing all the improvements the district needs.

To save money, Starr had proposed delaying 20 projects to revitalize existing schools. The board’s action Monday did not spare one-year delays for 15 elementary school projects, but it kept middle and high school projects on their current timetable.

If county officials approve the plan in coming months, construction timetables for high schools including Thomas S. Wootton and Poolesville, and middle schools including William H. Farquhar, Tilden and Eastern would be restored.

Board members acknowledged that securing necessary funding would be no small challenge. But they also said they were seeking to respond to community concerns about secondary school projects, many of which have faced multiple delays amid financial constraints. Such projects rebuild schools from the ground up, providing brand-new buildings.

“It’s never going to be easier,” said board member Patricia O’Neill (Bethesda-Chevy Chase), who noted “a tug of war” between projects designed to address increasing enrollment and those that upgrade existing facilities falling into disrepair. “If we don’t put this stake in the ground on secondary schools, they just will be deferred forever.”

Montgomery’s enrollment has surged by 14,000 students since 2007. Nearly 151,300 students attend classes in the county’s public schools, with an additional 11,000 students projected during the next six years. This school year, Montgomery swelled by 2,510 students, enough to fill more than three elementary schools.

In seeking to preserve plans for middle and high school projects, board members pointed out that the district’s surging enrollment hit elementary schools first and will soon take hold in middle and high schools.

“I think it would be prudent for us to be proactive in addressing the surge before it comes rather than reactive and dealing with it after it gets here,” Kauffman said.

The six-year plan the board adopted also steered $16.6 million to the Blair Ewing Center, which houses alternative-education programs for struggling students.

Board President Christopher S. Barclay (Silver Spring) described the project as a priority, and other leaders agreed. “That facility should be no less attractive and conductive to their improvement as any other school,” board member Michael A. Durso (Eastern County) said.

The board’s decision followed a week of packed public hearings that drew parents and students from across the county who testified about crowded schools, deteriorating facilities and broken mechanical systems.

Janette Gilman, president of the countywide council of PTAs, told board members at one hearing that parents had accepted recession-driven delays in the past but no longer could “accept all that has been left out” of its plans to build and improve schools.

In an interview after the Monday decision, Gilman said that even though the plan did not go as far as she believes is needed, she was pleased. “I’m happy to see they are pushing the envelope on this one,” she said.

The board’s proposal will be submitted to the County Council and county executive, starting a process that extends over months and will include more hearings.