As Palo Alto's senior population continues to expand, the downtown nonprofit that serves this growing population is trying to do the same.

Avenidas, which has been providing classes, workshops, case management and other services to area seniors since 1977, is now preparing for a major addition to its 1927 Birge Clark-designed building at 450 Bryant St. On Oct. 19, its effort could get a major boost when the City Council considers contributing $5 million in public funds to the project.

For Avenidas, the expansion aims to both meet the increased demand for its services and upgrade an aged structure that originally housed the city's police and fire departments. The project would supplement the existing 16,000-square-foot building with an 11,000-square-foot wing, creating a new Wellness Center and an upgraded technology center that would connect seniors with researchers and entrepreneurs who create products for that population.

But before construction can begin, the organization has to raise $18 million to cover the costs. In April, it requested a $5 million contribution from the city, which owns the building and last year agreed to extend Avenidas' lease by 50 years. Specifically, the organization is asking for funding to pay for seismic upgrades and the replacement of its mechanical, electrical and plumbing systems.

Avenidas CEO Amy Andonian, board of directors Chairman Bruce Heister and Capital Project Manager Lisa Hendrickson wrote in their April letter to the city that the expansion would "bring the building into the 21st century and assure its relevance for many years to come." The city's contribution would, in the near term, help Avenidas raise the rest of the needed funding, according to the letter.

"We are learning that many of the prospective donors to this $12 million campaign expect that the city will make a meaningful investment in this project and its building," the letter states. "We would be able to leverage the city's commitment and accelerate our fundraising if the city makes a commitment soon."

Earlier this year, the organization requested $5 million to fund about $3.3 million in upgrades and another $1.98 million to cover the fee Avenidas would have to pay to comply with the city's parking requirements. Since then, the costs for rehabilitations have gone up and the entire request is now for building upgrades, according to Hendrickson.

Palo Alto has a long history of supporting Avenidas, which provides the types of senior services that other cities typically fund from their respective General Funds. The council in 1978 made a decision to transfer senior services to a nonprofit and provided initial funding for the center's operation, a new report from the Community Services Department states.

"Since that time, the city has provided significant funding to Avenidas for the provision of comprehensive services to older adults in Palo Alto," the report notes.

At one point, the report states, this support comprised 38 percent of the organization's total operating budget. Today, it totals 10 percent.

Meanwhile, one-third of Palo Alto residents are now age 55 or older -- a proportion that is expected to grow to 50 percent by 2030. The staff report notes that in Palo Alto and surrounding cities the senior population is set to double between 2000 and 2020. The report notes that last year Avenidas served more than 7,000 individuals and hosted 233 classes.

While no one is questioning the need for more senior services, the modernist design of the proposed addition has already attracted some criticism. During a July hearing, members of the city's Historic Resources Board struggled to reconcile the differences between the existing two-story Spanish Colonial building and the contemporary three-story addition. Beyond the stylistic disparity, the addition calls for the removal of the existing building's historic eaves and roof sections -- a sacrifice that board member David Bower said was unacceptable.

Because the July meeting was a preliminary hearing, the board did not vote on the project, which is now undergoing revisions based on feedback from staff, the historic board and the Architectural Review Board.

The council, for its part, will focus on the funding component. Though the expansion of Avenidas was not included in the council's recently adopted infrastructure plan, staff from the Community Services Department is recommending that the city comply with Avenidas' request. The Community Services report notes that the organization "has covered the increasing cost of providing services to an ever-increasing number of Palo Alto older adults, with a budget that has grown less than three-fold during the same time."

"They believe that this request gives the city the opportunity to make an investment in the future of high quality senior services and facilities," the report states.

More than half of the city's contribution could come from the sale of "transferable development rights" -- a mechanism that provides development bonuses to seismic or historical rehabilitation projects. These density bonuses can be used either on the projects undergoing renovation or for off-site projects.

According to staff estimates, the sale of these rights could raise about $2.8 million. The remaining $2.2 million would come from the city's Community Center Development Impact Fee Fund.