The Prince William County School Board, in an unusual special meeting last week, approved a $21.4 million deal with the Board of County Supervisors to create more class space for students.

School Board members voted 5 to 3 late Wednesday in favor of the proposal written by supervisors Peter K. Candland (R-Gainesville) and Frank J. Principi (D-Woodbridge). It says the supervisors will provide the money to the School Board in exchange for the School Board’s approval of design changes to plans for Prince William’s 13th high school, scheduled to open in 2021 in the western part of the county.

The design changes would make room for 500 additional students at the high school, pushing its capacity to more than 2,500, county government and school officials said.

Supervisors are expected to allocate up to $10.7 million on Tuesday for the modifications.

They also are expected to vote to provide another $10.7 million — totaling the promised $21.4 million — to the School Board for capital projects in Prince William’s eastern end. The School Board would determine how that money would be spent, Candland said. For example, it could be used to buy land for schools, build new schools or add on to existing buildings.

The arrangement between the two boards would mean more educational space for students on both sides of the county, Candland said. School Board members voting in favor of the pact underscored this notion, as well.

But two School Board members who represent portions of eastern Prince William, Lillie G. Jessie (Occoquan) and Loree Y. Williams (Woodbridge), expressed reservations about the supervisors’ proposal.

“There’s a lot of missing pieces,” Williams said, despite the fact that Candland, Principi and three other supervisors in the eight-member body sent a letter to School Board members, assuring them of the sincerity of the offer.

Jessie, Williams and School Board Chairman Ryan Sawyers (At Large) cast the votes against the financial deal.

Sawyers maintained it was illegal for the supervisors to provide money to the school system unless it came with no strings attached, and he initially resisted even participating in the special meeting, saying it wasn’t properly called.

The session was held immediately after the School Board’s regular Wednesday meeting. The chairman left the board chambers as members Alyson A. Satterwhite (Gainesville), William J. Deutsch (Coles) and Shawn L. Brann (Brentsville) tried to get the special meeting started.

Lawyers for the School Board and supervisors agreed that the funding package was legal, however, and that the special meeting was deemed legally called, so Satterwhite was allowed to gavel it to order in the absence of Sawyers and Jessie, the vice chairman, who also left the dais for a brief period.

Before discussion about the funding began, all board members had returned to their seats.

Williams unsuccessfully moved to delay a decision on the money. Justin David Wilk (Potomac) voted in favor, and the deciding fifth vote for the $21.4 million deal was cast by Diane L. Raulston (Neabsco).

Raulston initially expressed skepticism about the deal. But, after the meeting, she said she couldn’t turn down extra resources.

“It’s money,” she said. “All school divisions in this country need money.”

Contacted the day after the vote, Candland said he expected the School Board to eventually approve the funding agreement. But he said drama surrounding the special meeting made him nervous.

“I was happily surprised that that passed,” he said of the deal.

The supervisors plan to appropriate the $10.7 million for the county’s eastern end Tuesday, according to Candland, meaning the School Board can quickly spend the money instead of waiting for the next fiscal year, which won’t begin until July.

He also said he and Principi, who aren’t known for agreeing on many issues, crafted their proposal specifically so it wouldn’t favor one side of the county over another, or benefit one political party to the other’s detriment.