Ken Weinstein, entrepreneur and developer, is well-known for rehabbing properties in Mount Airy. Now, he's turned his sights on Germantown, buying and refurbishing historic or vacant buildings and turning them into modern apartments and stores.

"Germantown is still high-risk, low-cost, as far as development goes," Weinstein said in a recent interview. "It's not hot yet, but it's growing. Mount Airy shows what Germantown could be."

Weinstein is now one of the larger property owners along Germantown Avenue, having invested $18 million. He's even put in a bid to redevelop the famed Germantown YWCA building near Vernon Park with MissionFirst, a nonprofit developer, proposing to keep the outer shell and the mural and renovate the interiors into affordable senior housing.

Across from the Y is Weinstein's newly renovated Cobblestone Flats at 5301 Germantown Ave., 11 apartments and a street-level café opening this year after conversion from a storage facility. Weinstein bought the building in 2011 for $5 million; the café will be run by Marvin Graf, owner of the East Falls Tavern, who plans a brick-oven pizza restaurant.

"We're adding density to Germantown Avenue, and that brings more energy," Weinstein said. Cobblestone Flats "is the largest renovation in dollars and size on lower Germantown Avenue."

"Germantown is at a very different state of development," he said, "but we are hell-bent on removing blight and renovating or restoring vacant commercial properties in what used to be the second busiest business corridor in the city as recently as the 1950s."

Weinstein wants to replicate in Germantown what he did in Mount Airy. Six months ago, the Germantown Special Services District, a business-improvement committee, was created to pick up trash and help revitalize a neighborhood with housing stock dating back to the mid-1700s.

Through his company PhillyOfficeRetail, Weinstein's model is to buy, own, and operate mixed-use buildings, incorporating into them new apartments and office space - take Mount Airy Presbyterian Church at Germantown and Mount Pleasant Avenues, which he currently is rehabbing. The church will lease the sanctuary part of the space, and the rest will be renovated into apartments. BWA is the architect on the $4 million project.

Weinstein's model has helped him survive real estate boom-and-bust cycles.

"What got us through 2007 and 2008 was cash flow" from owning and managing rental buildings, he says. "We don't buy expensive Center City buildings and wait for appreciation. We buy for good tenants."

Weinstein already has rehabbed 7047 Germantown Ave., a former funeral home converted into an office center, and commercial lofts called Kendrick Mills, a former knitting mill at 6139 Germantown Ave. Weinstein invested $400,000 into the 25,000-square-foot mill. It is fully occupied by tenants including musicians, artists, a children's clothing maker, and other small businesses.

He has also bought, rehabbed and leased 5847 Germantown Ave., a former welfare-office building at the corner across from long-vacant Town Hall. The new tenant is Philadelphia Works, which has leased 30,000 square feet starting in September.

As proposed by Weinstein, MissionFirst would lead the development of the YWCA into senior apartments and own and operate the facility, while Weinstein would develop a vacant lot next door into commercial space in partnership with MissionFirst, which develops low-income housing for seniors and veterans. The nonprofit Center in the Park would also be a partner.

Apparently, not everyone is happy with that plan, though. Councilwoman Cindy Bass, who represents the area, must sign off on any plan for the property and has yet to endorse the joint Weinstein-MissionFirst bid. Her office did not offer any details why; a response had been expected in early January.

Soon, there will be public input. Germantown United Community Development Corp. wants to weigh in and plans a public meeting later this month, and the Preservation Alliance also is interested in the fate of the project.

Solid tenants have not yet signed on at Weinstein's project at the former St. Michael of the Saints church and school, which sits on a six-acre lot on lower Germantown Avenue, within eyeshot of Louden Hall in Fairmount Park. Still, Weinstein hopes the $25 million city redo of SEPTA's Wayne Junction will be a boon to the area.

"Germantown has been left out of everything. Our goal is to make it less risky."