Students are often required to "show their work" when handing in math homework or a test.

The Board of Selectmen has asked the Fairfield Ludlowe Building Committee to do the same thing after hearing a report on the high school building/renovation project where the cost has ballooned from the authorized $11.6 million amount to more than $15 million.

Last week, the selectmen asked building committee officials to return when they meet March 4 with more details on why the project is over budget.

The construction project calls for replacing roofs and windows at the high school, building an 8,900-square-foot classroom addition and expanding the cafeteria.

"What are the top-10 reasons?" First Selectman Michael Tetreau asked. "I understand the costs are higher, why are the costs higher?"

Tom Cullen, director of operations for the Board of Education, said part of the issue is that "soft costs" were not included in original budget estimates. Soft costs usually cover things like architectural and engineering fees, testing fees and the cost of construction managers and owner's representatives.

"It didn't have adequate contingencies," Cullen said. "More environmental testing was required than I think was anticipated."

Selectman Kevin Kiley said what is needed is a "bridge analysis," which would show where the costs of items increased and where some costs may have decreased.

"I think as we track the status of the budget, I think we can assemble this," Cullen said.

"We're looking for the drivers," Tetreau said. "What are the things that are making these costs go up?"

Tetreau said the increase is such a large number that the selectmen were having a hard time "getting our brains wrapped around this."