Five years after the attacks of September 11, 2001, ground zero is a pit, a monument to intergovernmental feuds that have stalled construction. But steps away, a giant crane is topping off construction on a soaring new luxury apartment building, the latest in a series that have sprouted in Lower Manhattan.

While it could take years for construction at ground zero to reach street level, the 396-unit luxury apartment building at 10 Barclay St. has been rising like a weed on Miracle-Gro this summer and will be topped off at 50 stories in the next month. It will be the residential tower that has been built closest to ground zero since the terrorist attacks. Apartments will be ready to rent as soon as this spring, according to the developer, Glenwood Management Corporation.

The executive vice president of Glenwood Management, Gary Jacob, said that in contrast to government projects, “things seem to work a lot faster when you are working on your own.”

As the five-year anniversary of the attacks approaches, 10 Barclay St. is a symbol of a booming downtown residential real estate market that was once a question mark. In the aftermath of the attacks, the city, state and federal government offered rent subsidies to keep residents in Lower Manhattan out of concern that occupancy rates would plummet. That program expired after two years, but now the residential population of Manhattan below Chambers Street has grown by more than 50% since 2001, to 36,000, according to the Alliance for Downtown New York.

The site of 10 Barclay St. was formerly home to a parking lot, a small commercial building, and a rectory.The developer purchased the much of the building lot in 2000 from Rolaco Services, a Saudi Arabian company whose founder, Abdul Aziz Abdullah Al-Sulaiman, was named a billionaire by Fortune. After the attacks, in 2002, Glenwood purchased the air rights from the adjacent building, St. Peter’s Roman Catholic Church, and transferred them to their building site.

The total estimated project cost is $185 million, and in 2005 the state awarded the developer $135 million in tax-exempt Liberty Bonds, part of a federal program devised to spur revitalization downtown. Under the program, 5% of the units must be “moderate income” housing.

Designed by the architectural firm Costas Kondylis & Partners, the tall, slender building skeleton now visible as part of downtown’s skyline will be clad in brick and limestone. It will contain a 75-car parking garage, an indoor swimming pool, a tenant’s lounge, a playroom, a conference center, and a theater.

Mr. Jacob said that the terrorist attacks of September 11, 2001 never caused the developer to lose faith in the project, but he said that it caused logistical delays that slowed their construction plans.

Despite rising construction costs, Mr. Jacob said the delay would increase the building’s profitability, as soaring rents in recent years will allow them to charge considerably more for the apartments.

“The downtown rental market is very, very strong. Downtown has come back in a very big way,” Mr. Jacob said. “We are really optimistic about the rent-up prospects next spring.”

Less than two blocks from 10 Barclay is the 16-acre void where the Twin Towers once stood. After years of delay and false starts, stemming from protracted negotiations between a myriad of stakeholders, including the city, the state, the Port Authority, and developer Larry Silverstein, construction began on the Freedom Tower in April.Work on the World Trade Center memorial resumes this month after a redesign and cost cutting process stalled the construction, which began in March.

The memorial is expected to open in time for September, 11, 2009, and the 1,776 foot tall Freedom Tower could be complete by 2011.

Mr. Jacob said: “I would have preferred a little more progress. Let’s put it that way.”

Downtown’s housing stock has grown by more than 5,800 units, or a 38% increase, in the last five years, according to a recent report by the Downtown Alliance. About 4,700 more apartments are currently under construction, and the organization expects the residential population to rise to 50,000 by 2010. Since the terrorist attacks, 14 residential towers have gone up south of Chambers Street, according to the report.

A partial building permit was issued last week for a 68-story building with 650 units, designed by architect Frank Gehry and developed by Forest City Ratner, planned to the east of ground zero at 200 Beekman St. At more than 800 feet, it will be one of the city’s tallest residential buildings.

Much of the residential growth downtown is in the form of conversions to apartments from aging office space — about 12 million square feet in the last five years, according to a recent report by the real estate firm, Jones Lange LaSalle.

Only one commercial tower has been completed in Lower Manhattan, 7 World Trade Center, owned by Silverstein Properties.Goldman Sachs is hoping to complete a new headquarters near ground zero in 2009.

The developer of 10 Barclay St., Glenwood Management, is controlled by Leonard Litwin, a veteran developer of rental properties who has developed over 3,000 units across the city. The company also received $95 million in Liberty Bonds to build 10 Liberty St., a 45-story, 287-unit rental building that is now open for business in the Financial District.

Over the next few years, private entrepreneurs and the city, state, and federal government will dump an estimated $20 billion into construction projects in Lower Manhattan, potentially filling the streets with traffic, pollution, and noise.

But Mr. Jacob is confident that 10 Barclay, steps from all the anticipated construction at ground zero — including three giant office buildings around the corner on Church Street — will still be desirable to potential tenants.

“I think the fact that there are more office buildings there will only enhance our rental buildings and increase the demand,” he said.