PORTLAND — The Cumberland County Civic Center board this morning backed a renovation plan for the aging arena that’s expected to cost about $28 million.

The renovation plan was selected by a Civic Center task force, based on the recommendation by consultants, earlier this fall.

The board’s vote did not include a dollar amount. Board chairman Neal Pratt said the project is likely to end up costing around the $28 million estimated by consultants, but it will be up to a building committee to come up with a more detailed price tag and work schedule.

Pratt said he expects that a committee will be selected in the next few months and it will come up with a figure for a renovation bond that’s expected to go on next November’s ballot.

The renovation plan calls for adding premium seating and improving other public areas of the 35-year-old arena, such as concessions and the box office. Other work will be aimed at behind-the-scenes areas, such as a larger loading dock and better dressing areas and locker rooms.

In approving the renovation plan developed by the task force, the board essentially rejected a competing proposal by developer Jason Snyder. He has proposed building a new arena on land he owns in Westbook or Portland and converting the downtown Civic Center to a convention center.

Snyder said his arena would cost about $85 million and he estimated the cost of converting the Civic Center at about $30 million.