An image of what the renovation to the Edgewood building on Charlestown's campus would look like. Construction is expected to be completed by January 2013. ( Image provided by Erickson Living / March 19, 2012)

A $28 million renovation project in three phases will add more residences and new amenities to Charlestown retirement community by spring 2013.

The move comes in response to increased demand from aging baby boomers and the high rate of those age 65 or older in southwestern Baltimore County, said Charlestown spokesman Jeff Getek.

The renovations, which began in January, will add 55 apartments, four elevators and recreation features, such as an expanded pool and workout facility, Getek said.

"It's been in the works for a while," Getek said. "A lot of planning now is taking fruition with construction on campus."

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Of the 55 new apartments to be added to the Edgewood building, 17 are one-bedroom and 38 are two-bedroom units, Getek said.

Of the 17 one-bedroom units, a dozen will have a den, Getek said.

The refundable entrance deposit for the units ranges from $79,000 to $475,000, based on size and floor plan, Getek said.

Renovations to Charlestown Square will include an expansion that nearly triples the size of the fitness center to 4,300-square feet, expanding the 20- by 48-foot pool to 30- by 75-feet and adding more than 20,000 square feet to the 35,000-square-foot clubhouse, Getek said.

The third phase of the renovation will add four new elevators, Getek said.

According to the website of the United States Census Bureau, 17.2 percent of Catonsville's population is over age 65.

That county average is 14.6 percent, the website stated.

Of those people living in Arbutus and Lansdowne, 12.2 percent and 11 percent are 65 or older, respectively, the website stated.

The design architects for the project are Marks, Thomas Architects in Baltimore.

The general contractor is Harkins Builders in Marriottsville, Getek said.