Minneapolis and Timberwolves officials announced Monday a deal to roughly split the cost of a $100 million renovation of downtown's city-owned Target Center, nearly three years after the plan was first outlined.

The face-lift will redesign the exterior of the 23-year-old building, create additional gathering spaces, improve pedestrian traffic flow, upgrade amenities, increase the seating capacity, add additional VIP clubs and fix loading dock problems. It is expected to make the building more competitive for concerts, as well as a better home for the sports teams.

The agreement, which must be approved by the City ­Council, would commit $48.5 million in city sales taxes to the renovation, plus another $43 million from the Timberwolves. Venue operator AEG would kick in another $5.5 million.

"It took a little while, but we got it done," Mayor R.T. Rybak said at a news conference in the lobby of the building. In addition to the upfront renovation commitment, the city will also be on the hook for $50 million in ongoing capital improvements — a responsibility that comes with owning the building.

The deal keeps the Timberwolves, Lynx and AEG at the arena until 2032. Despite an elaborate rollout, city officials declined to make the full term sheet of the agreement ­available on Monday.

Rybak said the average visitor to Target Center will experience a "freshened and more exciting" exterior, more open common areas and more efficient ways to exit the building.

"We are so appreciative of our fans," said team owner Glen Taylor. "And now to have them come to a facility that will even be nicer, I think will be a great treat for them."

If approved by the council, construction could begin in spring or summer of 2014 and continue for 18 to 24 months. It will occur in phases and allow for continued use of the building for most, if not all, of that time, Rybak said.

The cost of the renovation was initially pegged at $150 ­million, but that cost was scaled down during negotiations. Rybak said the city had already expected to spend the $50 million in capital improvements, regardless of the deal.

"The bottom line is had this deal not been done, we still would have been putting money into this building ongoing," he said. "But it would have deteriorated much more rapidly."

Rybak has said that the Vikings stadium deal was needed to spend restricted city sales tax dollars on the renovation. Because of that, he asserts it has saved property taxpayers $5 million a year. Others, such as Rep. Diane Loeffler, DFL-Minneapolis, said those sales taxes could be used for this purpose without the Vikings deal.

The City Council will hold a hearing on the agreement this Thursday, with a full vote expected on Nov. 12. Several City Council members were supportive when queried on Monday. In contrast to the controversial Vikings stadium deal, the city already owns this building — a 1990s decision many current City Hall ­inhabitants say was unwise.

"It's not as controversial because this is an asset that the city is responsible to maintain," said Council Member Gary Schiff. "And nobody on the council today voted to buy it. So this is a liability that current leaders are responsible for."

Council Member Lisa ­Goodman, who represents the area, said the alternative would have been to let the building deteriorate until the Timberwolves tried to leave.

"When that building is dark, you can really feel it downtown," she said. "So unless we were willing to abandon the building and repurpose it, we had to do something."

Todd Klingel, president of the Minneapolis Regional Chamber of Commerce, noted at the news conference that Target Center draws 200 events and 1 million people each year. "We're putting our stake in the ground for the future of maintaining the vibrancy of this region," he said.

Officials Monday also stressed the value of the fixing up the aging building over building an entirely new facility.

"I would have liked a new facility," Taylor said. "But I'm a Minnesotan. I served in the Legislature. I know about taxes because I pay a lot of them."

Eric Roper • 612-673-1732

Twitter: @StribRoper