The Aurora school district has come up with a finance plan to start construction of a new school building for the district’s first DSST charter school.

The district and the Denver-based charter organization disagreed early on about who should pay for the new building, which will house the combined middle and high school charter the board approved in 2017. Aurora Superintendent Rico Munn offered to pay half with bond money voters approved in 2016, but asked DSST to pay the other half.

DSST leaders said they would not pay for a building they wouldn’t own, but would help the district fund-raise.

The plan presented Tuesday night, which the board will consider next month, combines those initial ideas.

The district has raised $4 million in donations toward the building. Munn assured the board that the district will still not pay more than 50 percent of the building’s cost, estimated to be $39.7 million. To buy more time to raise more funds, the district would split construction into two phases. That would still serve the charter, which plans to open with just sixth graders, growing by one grade level per year.

In the first phase, the district’s contractor has guaranteed a maximum cost of $21.2 million, for which the district will cover the start of work this fall with $12 million in bond funds.

After the bond money and the fundraising dollars, the remainder of the first phase cost will be covered by DSST, paid to the district over time through a facilities fee.

In the meantime, Aurora will use certificates of participation, a borrowing mechanism for governments, to temporarily cover that DSST portion, up to $6 million.

The plan still needs board approval next month, but there were few objections raised this week. The terms for the certificates of participation will also require separate board approval, but likely aren’t necessary to start construction. District officials hope that if they can raise more money in the meantime, they won’t need to borrow as much.

For now, the district is proposing to charge DSST $1,100 per student for the facilities fee to cover the cost of the payments on the debt.

Aurora staff pointed out that the facilities fee is higher than the $773 per student that the charter organization pays for space in Denver.

“That’s important to highlight that commitment to close the gap,” said Brett Johnson, the district’s chief financial officer.

In Aurora, only one charter school operates in a district building. That school, Rocky Mountain Prep, which the district selected in 2016 to take over a struggling school, pays an annual facilities fee.

The charter school, Aurora Science and Tech, or AST, as it will be called, will open this fall sharing space with Rocky Mountain Prep while waiting for its own building.

In 2017, the school board approved DSST’s application to open four schools — two middle and two high schools — starting with one middle school in the fall of 2019.

The school already has enrolled 175 students, including 28 who live in Aurora but have been attending school outside the district, Peter Sherman, the AST founding school director, told the board.