Pittsburgh already has the world's largest certified green building in its convention center. Now PNC Financial Services Group wants to add to the collection.

PNC officials said yesterday that the 23-story skyscraper it is erecting on Fifth Avenue, Downtown, will be the largest environmentally friendly mixed-use building in the United States when it opens in late 2008.

It will be designed and constructed to meet Leadership in Energy and Environmental Design (LEED) standards established by the U.S. Green Building Council. At least 50 percent of such construction materials as structural steel, carpet and paint will be made from "green" or recycled materials.

While green construction can cost a little more, PNC sees long-term savings in maintenance and energy consumption, said Gary Saulson, director of corporate real estate.

"We think it's the right thing to do for shareholders, employees and customers," he said.

Work on Three PNC Plaza, the city's first new skyscraper in two decades, is expected to start in August with the deconstruction of 13 PNC-owned properties on Fifth Avenue between Wood Street and Liberty Avenue.

The building will feature 11 stories of office space, nearly half of which will be occupied by the venerable Downtown law firm of Reed Smith. PNC is expected to take the rest of the office space.

An upscale hotel with 185 rooms, about 35 more than originally planned, will occupy the upper 10 floors along with 30 luxury condominiums. The condos and hotel will share floors, but be separate from each other, with access by different elevators.

The design enables PNC to have three condos to a floor, each with "phenomenal views" of the city below, Mr. Saulson said. The condos will sell for about $300 a square foot, he said.

PNC, which unveiled the final design of the building yesterday, decided to add more hotel rooms because of "demand in the market," Mr. Saulson said. It currently is negotiating with a potential hotel operator, one he would not name.

"It's a well-known hotel flag," he said. "It will be a step above the Renaissance, which I think is probably considered the highest-end hotel in Pittsburgh today."

Rounding out the construction will be retail and restaurant space on the first floor and a 300-space parking garage underneath the building. Mr. Saulson said interest in the project has been high, with potential retail and restaurant tenants seeking out PNC.

"I just think there's a lot of excitement with regard to what is happening in the corridor," he said.

Total cost of the project is expected to be in excess of the original $170 million price tag, largely because of the additional hotel rooms.

The building is being financed with the help of $48 million from public sources -- $30 million from the state and $18 million in tax increment financing. The project is expected to generate 800 on-site and indirect construction jobs with a payroll of $35 million.

PNC also expects to add 1,000 employees in Pennsylvania in the next three to five years, with some working from the new building. It will be next to PNC headquarters at Fifth and Wood Street.

The bank has opened 24 "green" branches since 2002. Its Firstside Center also is environmentally friendly. Overall, Pittsburgh ranks as among the top five cities nationwide for green construction.