Kansas City Mo. ? A movable roof that would make the Kansas City Chiefs’ Arrowhead Stadium a candidate for a Super Bowl could cost Jackson County taxpayers around $200 million, architects for the project said Friday.

That would be in addition to $575 million in renovations planned for Arrowhead and nearby Kauffman Stadium, which would be paid for through a mix of team money, state tax credits and a local sales tax that officials hope next week to put on the ballot for April 4.

But supporters of the roof, to be partly paid for with a sales tax of its own, said the first-of-its-kind structure could do more for the region than attract football’s biggest event.

“This has never been done in the world,” Dennis Wellner, a principal with the HOK Sport and Venue and Event design firm that designed the roof, told county legislators Friday. “It is the symbol for taking the complex into the future.”

Jack Steadman, the Chiefs’ vice chairman and lead negotiator, said the timing was right.

“Why would you not do a renovation of the sports complex in such a way that will excite the entire community?” Steadman said after the hearing. “This really puts the cap on what is really one of the beautiful complexes.”

A movable roof, which first was contemplated when Arrowhead and Kauffman were built more than 30 years ago, resurfaced Thursday when county officials released updated lease agreements with the two teams.

Wellner showed early designs for the roof, a fan-shaped series of Teflon-coated fiberglass panels that could be moved on a 2,400-foot set of elevated rails to cover either Arrowhead, Kauffman or an empty region between the two stadiums, the possible site of concerts or other sporting events. Additional panels would be installed along the sides to retain heat during the winter. NFL officials said in November they would hold a Super Bowl in Kansas City if Arrowhead could protect attendees from the sometimes difficult weather in early February.

To pay for the roof, team and county officials are proposing that voters approve a “compensating use tax” on large purchases made by Jackson County shoppers from merchants outside the state. The city of Kansas City and most surrounding counties already charge the use fee.

Officials estimate the use tax would provide about $150 million for the roof over 25 years, meaning they still must find $50 million, possibly through naming rights for the structure.

The county, which owns the Truman Sports Complex, is seeking new leases with the Chiefs and the Kansas City Royals. The current agreements with the teams expire in 2015, but the county is worried it could default on the leases by the end of the year without new revenue for a backlog of repairs at the stadiums.

The new leases, to expire in 2031, call for a 3/8-cent sales tax in Jackson County to supply $425 million over 25 years, $50 million in state tax credits and $100 million from the teams themselves. In addition, the teams have agreed to pay for any cost overruns.

Besides the taxes, the Chiefs have proposed a user fee added to tickets and a 10 percent fee added to parking to cover routine maintenance at the complex. The Royals, however, so far have avoided adding a ticket fee.

The teams are expected to sign the new leases Monday. County legislators are scheduled to vote later Monday or Tuesday to put the two sales-tax issues before voters on April 4.