The Montgomery Planning Board recommended historic designation for the 50-year-old Wheaton Community Recreation Center Thursday night, concluding that there was no evidence that justified razing it in order to build a new rec center and library on the same site at Georgia and Hermitage avenues.

But the board also acknowledged that the old building might be too costly to renovate, or that there may not be any use for it that was worth the expense. It left an opening for Montgomery officials to make that case to the County Council — which has the final say — early next year.

Wheaton residents had spent years lobbying for a new recreational facility to replace the old center, plagued by a leaky roof, mold, warped floors and other signs of decay. Last year, the council set aside money in the capital construction budget for a new combined rec center and library. Tentative plans call for construction to begin in 2016.

In September, however, the county’s Historic Preservation Commission found that the old rec center, designed by D.C. architect Arthur Keyes with an unusual curving, pagoda-like roof, courtyards and large, exposed wooden trusses, had value as an exemplar of “Asian-influenced modern design.” The commission also gave a nod to the center’s role as a venue for rock concerts in the late 60s and early 70s. The finding triggered community concerns that the new facility could be delayed or changed.

The key moment in the two-and-a half hour hearing came when John Carter, a senior planner for the county, showed the board drawings indicating that as currently designed there was ample space on the site to keep the old building and still complete the 91,000 square foot rec center and library.

“You could keep the existing building and keep the design untouched by the proposed building,” Carter said.

But two officials leading the new construction project — Jeff Bourne, a division chief for the Recreation Department, and Greg Ossont, from the Department of General Services — told the board that retention of the old rec center would remove about 12,000 square feet of green space envisioned for outdoor recreation programs. Ossont also said there was no money budgeted to pay for the many repairs the old rec center would require.

Board chair Francoise Carrier said it was not the role of the board to manage decisions for the recreation or general services department. But the law required that the board make a determination about the historic value of the old rec center.

“I’m persuaded the building is historic. I’m also persuaded that this community needs a new rec center,” Carrier said.

In the end, the board agreed that the county had failed to make a compelling case that both goals — a new rec center and library, and preservation of a historic structure — could not both be met.

“If the [historic preservation] statute means anything, I don’t see how we can say that the public interest outweighs the historic design,” said board member Casey Anderson.

The board voted 4-to-1 to recommend historic designation to the County Council. Board member Norman Dreyfuss was the lone opposing vote.