The cost of a new roof for the Kennedy Middle School has risen from $1.5 million to $3.5 million because new state rules apply, David Dunkley, the city’s school building facilities director, told the School Committee Tuesday night.

The state School Building Authority, which will cover just over half the cost of “green” roof repairs, is requiring the city to meet the state building code for insulation, Dunkley told the committee, which also reviewed Dunkley’s budget.

Doubling the insulation means other building parts, such as windows and flashing, will have to be addressed, he said.

The state school building authority rules will make the project better, Dunkley said.

In addition, the state building code has just changed, requiring projects to meet seismic standards, Dunkley said. That alone will add about half a million dollars to the lower price tag.

The School Building Authority is willing to support the higher costs, according to Dunkley. Authority members will vote on the city’s green roof repair application on April 4 or 5, he said.

The cost increase is not due to the roof being in worse shape than school officials had thought, school Supt. Mark Donovan emphasized.

Dunkley said he will meet with Mayor Scott Galvin Wednesday on the roof issue.

The cost to repair the roof at the Joyce Middle School is about $1.7 million to $1.8 million, Dunkley said. That repair, too, is being proposed as a green project, with just over 50 percent reimbursement.