A series of design flaws in the plans to replace the ice rink in the Target Center has added more than $1 million to the project's price tag over the past year and a half.

In October 2016, after seeking contract bids to rip up concrete and rebuild the ice rink, the Minneapolis City Council accepted an offer from the sole bidder — a Liverpool, N.Y.-based company called Ice Builders Inc.

At the time, Ice Builders bid $2.5 million for the entire project, which city staff remarked was below the estimated $2.8 million cost. But the price on the project has continued to climb as the City Council approves more work orders related to fixing flaws in the project's design related to the rink's cooling system. As of this month, it's now up to $3.6 million, according to contract documents. It's still unclear who is responsible and who will ultimately pay the bill, but the city is picking up the tab for now.

City Council Member Steve Fletcher, whose ward includes much of downtown, said the city had to approve the change orders promptly so the project doesn't delay events already booked for the arena and incur even more costs from canceled shows. He said staff are investigating the source of the problems and the city will later attempt to recoup the money, even if it means taking legal action.

"I don't expect, in the end, for the taxpayers to pay for the error," said Fletcher.

A spokesman for Ice Builders did not respond to a request for comment.

The Target Center has been undergoing $140 million in renovations over the past few years. The ice rink was more than 25 years old and reaching the end of its life span, said Minneapolis spokesman Casper Hill.

Fletcher was not on the council when the project passed in 2016, but is now vice chairman of the Ways and Means Committee, which approved the third change order without discussion April 10. Committee Chairman Adbi Warsame declined to comment on the rising expenses.

The ice rink project, which city documents dub "highly specialized" work, consists of ripping up pre-existing concrete and piping, and replacing it with new concrete-encased steel beams, along with modification of the refrigeration technology to keep in line with environmental standards. Ice Builders is among only a handful of contractors with experience doing this specific type of work in the country, according to documents filed along with the bid.

The City Council approved two change orders for extra costs to fix design problems, totaling $454,040, in December 2017. It approved an additional $657,806 earlier this month.

Most of the money will go toward labor, equipment and subcontractor bills. About $90,000 covers travel, food, hotel for workers and other miscellaneous expenses, according to the expense summary.

The changes are already being made. Echoing Fletcher, City Attorney Susan Segal said her office will aggressively seek to protect the public from paying for the added expenses due to flaws in the construction design.

"We take seriously all expenditures of public funds and the city will certainly be seeking to recover any additional payments caused as a result," said Segal.