When it comes to the de Blasio administration’s school construction plans, pre-kindergarten, smaller classes, and middle school science labs are in.

What’s out: charter schools, classroom trailers, and the words “Children First.”

The Department of Education today unveiled a $12.8 billion plan to add 39,500 seats to the city’s schools by 2019. The plan adds 7,000 more seats than the Bloomberg administration had planned for, using $800 million in state funds that voters must approve. The details are outlined in a revision to the city’s five-year capital plan that supersedes a less expensive plan that the Bloomberg administration put out just two months ago.

“These revisions will help us create high-quality, full-day pre-kindergarten seats citywide that will deliver strong instruction,” Chancellor Carmen Fariña said in a statement. “The changes also will add seats to reduce class size among all grade levels — a longstanding and high-priority issue for communities throughout the city.”

The additional spending is dependent on the passage of the New York State Smart Schools Bond, a $2 billion pot of school infrastructure funds that Gov. Andrew Cuomo wants legislators to let voters decide on this fall.

A few of the changes to Bloomberg’s construction plan are cosmetic. The new plan renames Children First Initiatives as School Enhancement Projects, shedding Bloomberg’s trademark moniker for that budget line.

But most of the proposed changes reflect substantial revisions to the department’s educational agenda. The de Blasio administration wants to put its money where its mouth is on expanding pre-kindergarten access by adding 2,100 new seats and on improving middle schools by focusing science lab upgrades in those schools.

The de Blasio plan also redirects funds that the Bloomberg administration had earmarked for charter school construction. In the last five years, the department added 4,800 seats in schools run by charter organizations and other groups, and the city planned to spend $210 million more on that program in the next five years. The revised plan both omits a listing of past charter school projects and turns the $210 million into the pre-K initiative.

Charter school advocates reacted sharply to the capital plan, which does not allocate any money to charter schools. “This administration has a decision to make, and soon,” said NYC Charter School Center CEO James Merriman in a statement. “If they’re interested in results, they will make sure high-performing charter schools are fully included in the pre-K program, including maintaining capital funding. Otherwise, it will be clear that their move to push pre-K is more about ideology than about helping children.”

The new plan adds language emphasizing the city’s commitment to eliminating classroom trailers, and it also notes that $490 million of the expected $800 million in new funds will create new seats that will allow class sizes to be reduced. If the state bond does not pass, the city will not be able to dedicate funds to reducing class size, according to the plan.

The Panel for Educational Policy, which the mayor controls and is still missing appointees, will vote on the proposed capital plan at its March meeting.