PORTLAND — The construction company in charge of the renovation of the Cumberland County Civic Center wants to start construction this August with an eye toward completing the work in early September 2013.

Jon Dicentes, a senior manager for Cianbro, said the timeline is dependent on a building committee signing off on a final design and approvals from Portland officials for the work, which is estimated to cost about $28.5 million.

Dicentes told the building committee this morning that he will present a more detailed timeline and firmer budget for approval at the committee’s next meeting on May 9.

The plan calls for the work to be done in three phases.

The first phase would involve rebuilding the entrance at the corner of Center and Spring streets, where the steep “suicide stairs” would be removed. This phase would also include rebuilding the loading dock and installing new heating, cooling and electrical equipment.

Dicentes said phase one, which would be done while other events – particularly Portland Pirates hockey games – are still going on, will take until the end of this year to complete.

The second phase would focus on rebuilding the entrance on Free Street. The goal is to make the entrance at street level, eliminating stairs at that corner of the building’s exterior. The work could also be done around hockey games that are scheduled for early next year, Dicentes said.

The final phase would begin in April or whenever the 2012-13 hockey season ends for the Pirates. Dicentes said the building would be shut for this part of the work, which includes renovating the entire seating area, relocating and rebuilding restrooms, renovating concession areas and constructing a new entrance to the building from Spring Street.

Dicentes said the timeline calls for the work to be done Sept. 6, 2013.