St. Patrick's Cathedral in New York is set to go under a three year, $177 million facelift, the most extensive renovation of the building since the 1940s.

The first phase of the makeover is already underway for the neo-Gothic Roman Catholic cathedral located on Fifth Avenue. The landmark's facade as well as the choir loft and rose window inside are already shrouded in scaffolding.

The cathedral, which is the seat of the Archdiocese of New York, is in much need of repair. The marble and granite facade is pitted and cracked, the ceiling is cracked and the stained-glass windows need re-leading, according to CapeCodOnline.com.

Cardinal Timothy Dolan announced the renovation project on March 17, St. Patrick's day.

St. Patrick's will remain open during the renovation, with work paused only during Mass and other major events.

"The idea is to bring the building back to what it was in the 1880s," said Jeffrey Murphy of Murphy Burnham & Buttrick Architects, which is leading the design team overseeing the restoration work. "When it's all done, it will be cleaner and lighter. ... It will be like when the building was when it was built."

During the restoration, each of the 3,000 panels on the 73 stained-glass windows will be inspected, cleaned and re-leaded as needed.

The first phase of the work, which will include work on the roof and the cleaning and repairing of the bronze doors leading into the cathedral, will take 22 months.

According to Msgr. Robert Ritchie, the rector of St. Patrick's, $50 million has been raised for this first phase from donors, cathedral trustees and the archdiocese.

The second phase is expected to start in early 2013. Work on the cathedral will include the rest of the interior up to the altar and remaining stained-glass windows and new heating and air conditioning systems.

The third phase will begin in the fall of 2013 and include the altar and the Lady Chapel behind the altar.

Bast said 250 to 300 tradespeople will be working on the site, and up to 1,000 people, including consultants, overall.

St. Patrick's Cathedral, which is named after the patron saint of Ireland, celebrated its first Mass in 1879. Even though it is not the largest Catholic church in the U.S., it is one of the best known and most visited.