Delaware City Schools has what it calls a deal for its taxpayers: a plan to add classrooms or install upgrades at all its school buildings with no increase in property taxes.

It will appear on the May 7 ballot in the form of a "no-new-millage" bond issue.

Superintendent Paul Craft said the issue's passage would allow the district to transfer payments from older, retiring bonds to the new bond issue. While it would be a first for Delaware, the concept has been used in other nearby districts.

"It's something that you really only get a chance to do when (your district) has been growing for as long as we've grown," Craft said. "Dublin and Olentangy have used this. ... We've now been growing long enough ... that we're able to start doing it."

While the issue will be listed on the ballot at 2.37 mills, the net effect is the additions can be built "without raising anyone's taxes," he said.

Among other improvements, the $36.5 million, 37-year bond issue would add new classrooms to Schultz, Conger and Woodward elementary schools, with the most expansive project planned at Schultz.

The plan is motivated by the district's continuing enrollment growth, Craft said.

The proposed additions "will set us up for the growth we're experiencing now and over the course of the next five to 10 years," he said, "so this should last (the buildings) through at least 2026-27 in terms of the growth we're seeing."

He said district enrollment has grown by about 100 students annually for the last 20 years, increasing from 3,714 students in 1990 to 4,954 in 2010. Enrollment now exceeds 5,800 students and is expected to increase to 6,444 by 2025, he said.

District Treasurer Melissa Lee said the bonds being retired are refunding bonds that were issued in 2013 as part of a cost-saving measure to reduce the district's outstanding debt. The bonds refunded at that time were from 2004.

"We have refunded bonds multiple times over the past 18 years to take advantage of interest-rate savings," she said. "Those bonds would have originated with Schultz Elementary (built in 1995), Dempsey Middle School (built in 2000) and the 1998 addition at Hayes High School."

Craft said the plan, as cleared with the county auditor's office, legally obligates the district to wait until each retiring bond is paid off before payments are transferred to the new bond issue, which would raise $36.5 million over its lifetime.

Triad Architects, Columbus, is working with the district on the planned building additions and renovations, said district spokeswoman Jennifer Ruhe.

While the district has a general plan, Ruhe said details won't be worked out unless voters approve the bond issue.

"On a practical note," she said, "the bond issue actually pays for some of that architect work as well (as any construction), so financially you have to have the bond passed in order to ask an architect to go to that level of detail."

Jason Sherman, the district's director of facilities and transportation, said the work at Schultz is "still being ironed out in terms of size and scope based on the enrollment projections, but we're looking at probably around six classrooms at Schultz at this point -- and along with six more classrooms, you're going to need to consider another set of restrooms and ... you're going to need to consider some more common spaces, possibly like an enlarged media center, maybe a bigger commons area."

Schultz covers 74,442 square feet at 499 Applegate Lane, Sherman said, and the construction is expected to add between 10,000 and 15,000 square feet.

With the additional students, Schultz also will need its own kitchen, he said.

"We're looking at a production kitchen at Schultz because right now we're preparing Schultz food at Willis (Education Center) and sending it over on a truck. So as that school becomes even larger, it makes more sense to prepare food there on-site than it does to prepare if off-site and move it on a truck."

Sherman said the district also hopes to perform some building upgrades at Schultz, such as work on the roof.

Also affecting details of the final plan, he said, is that "it's hard to come up with all of that detailed information before you go and present it (to voters), because inevitably (prices increase) with the cost of construction and the labor market. We've used other construction projects in the area to kind of give us a feel for what kind of price per square foot we're looking at, and then we can kind of start our planning off of that."

If voters approve the issue, Craft said, the first of the new bonds could be issued by July. Detailed planning would continue through October.

Triad Architects would be expected to seek bids and select contractors by December. Construction would start in March 2020.

"We look to break ground on several projects this time next year," Ruhe said.

Which projects will be started first is yet to be determined, Sherman said.

"However, right now it looks like Schultz and Woodward are probably the two more-pressing sites where we might experience some overcrowding, so we might want to go and address those first," he said. "But some of the smaller projects could happen simultaneously. ... We're not looking at a lot of major logistical issues that would stand in the way of delivering an education, so we are confident we can work around the normal schedule, the normal school day, the normal facilities with a lot of these projects."