The Suffolk School Board has approved a capital improvements plan that could result in about $80 million worth of new schools and administrative buildings being constructed during the next three years.

The School Board voted unanimously Thursday night to accept a capital improvements plan that sets school priorities for the next 10 years.

According to the plan, the first project to tackle is construction of a new $21.5-million elementary school in the 2010-2011 year, which would serve as a replacement for both Southwestern and Robertson Elementary Schools.

The plan also calls for a new $51.4-million middle school to relieve overcrowding at John Yeates Middle School and a $6.6-million school administration office to be constructed in 2011-2012.

Thursday was the first time the School Board had seen the cost estimates related to its capital improvements plan.

At their September meeting, School Board members received copies of the plan created by the Capital Improvements Plan Study Committee, which identified a replacement school for Southwestern and Robertson Elementary Schools as the school district’s number one priority.

While the committee’s report was thorough, School Superintendent Milton Liverman said, members made the decision not to include cost projections in the report because those projections would depend on the locations chosen and when the project begins.

Last week, the School Board met to discuss the plan and prioritize the projects.

On Thursday, Finance Director Michael Brinkley presented the cost estimates and the suggested pacing of the 14 projects the board tentatively scheduled for the next 10 years.

The only difference in the plan suggested last week and the one approved on Thursday was the addition of hazardous materials management costs, which cost $100,000 every other year.

That money is for the testing and abatement of hazardous materials as they surface, Brinkley said.

“We don’t request that money unless we spend that money,” Liverman said.

Board Member Michael Debranski questioned whether the amount allocated for the new school administrative building would be lower if the school system used one of its vacated buildings.

Liverman said that it would.

He added that by voting on the new plan, the School Board was not locking in these projects.

“This is a fluid document,” Liverman said. “You can make adjustments every year.”