View of St. Patrick's Cathedral's rose window in the organ loft
Raymond Pepi / Building Conservation Associates View of St. Patrick's Cathedral's rose window in the organ loft

The three-year, $177-million renovation of St. Patrick’s Cathedral in New York is nearing completion, just in time to welcome Pope Francis, who will lead evening prayer there on Sept. 24 as part of his first visit to the U.S. The landmarked Gothic Revival structure, designed by American architect James Renwick, Jr., was completed in 1888 with publicly raised funds. As a result, said Jeffrey Murphy, AIA, a founding partner of local architecture firm Murphy Burnham & Buttrick (MBB), during a Sept. 9 media tour, St. Patrick's became perceived as “America’s church” and was one of the first successful examples of religious architecture in the "new" world.

St. Patrick's Cathedral
John Baer/Building Images

Cracked interior columns and a crumbling exterior led American Cardinal Edward Egan to initiate a major restoration effort in 2006, more than 70 years after the cathedral’s last significant renovation. The project was put on hold during the Great Recession, but Murphy says the firm used the time "to research and determine the best possible [restoration] methods.” In total, approximately 20 consulting firms and 150 restoration specialists worked on St. Patrick’s in the last nine years.

Throughout its restoration, the church maintained the open-door policy instated by the resident Rev. Monsignor Robert Ritchie, receiving more than 5 million visitors each year. Ritchie echoed American Cardinal Timothy Dolan’s sentiment that the restoration process was a spiritual renewal for the church.

In addition to restoring the cathedral to its original 1888 design intent, MBB upgraded the building systems for safety and efficiency.

Years of pollution and neglect had turned the cathedral’s marble exterior from a creamy white to a dingy gray. The marble façade was cleaned with a Rotec system that used micro-abrasion to gently scrub the surface using low-pressure water, air, and crushed glass. The reconditioned marble now reveals stone varieties that tell the story of its construction: from grade upward, the material progresses from Georgia marble to Tuckahoe marble from Westchester, N.Y., on to Cockeysville marble from Maryland (which also clads the first 152 feet of the Washington Monument in D.C.), and finally Lee marble from the Berkshires in Massachusetts.

Workers survey the condition of a cathedral tower.
Courtesy Murphy Burnham & Buttrick Workers survey the condition of a cathedral tower.
Aerial view of the roof scaffolding at the church
Whitney Cox Aerial view of the roof scaffolding at the church

Hasty Portland cement repairs to the marble joints in the 1970s cured much darker than the stone. Furthermore, the mortar, which was harder than the marble itself, caused some of the blocks to crack. These joints were cleaned and re-pointed as a part of the restoration.

Repaired crack in exterior marble
Murphy Burnham & Buttrick Repaired crack in exterior marble
Exterior marble after (left) and before (right) its cleaning
Murphy Burnham & Buttrick Exterior marble after (left) and before (right) its cleaning
St. Patrick's Cathedral
Whitney Cox


A two-bay-wide, rolling scaffold system was erected around the church’s triforium, spanning the nave and its aisle. As workers moved the scaffolding from east to west through the interior, specialists from local restoration firm Building Conservation Associates meticulously inspected the cathedral’s stained and deteriorating ceiling to recommend repairs. The existing finish had been value-engineered following the Civil War with plaster affixed to wood lath ribs—a precursor, of sorts, to cast stone. Candle soot and air pollution eventually imbued the plaster with an olive-green hue. After the interior was cleaned with a chemical latex peel, three tints of cream paint were applied to the ceiling to reflect Renwick's design vision.

The restored nave ceiling
Whitney Cox The restored nave ceiling
Restoration specialists paint interior joints on the walls and ceilings.
Whitney Cox Restoration specialists paint interior joints on the walls and ceilings.
Works paint the interior plaster.
Murphy Burnham & Buttrick Works paint the interior plaster.

Fire Suppression
The ceiling plaster affixes to original timber laths, so updating the finish to meet modern fire-safety standards was paramount. After the plaster and church’s attic space were cleaned and repaired, the team installed a high-pressure, nitrogen-propelled, misting sprinkler system. This method, originally developed for maritime applications, requires a fraction of the water of conventional sprinkler systems to suppress a fire. To Murphy's knowledge, St. Patrick's is the first U.S. cathedral to use this system.

Vacuuming and cleaning the attic
Whitney Cox Vacuuming and cleaning the attic

Seventy-five stained-glass windows, comprising 3,700 unique panels, were restored by the Botti Studio of Architectural Arts, in LaPorte, Ind. A lite of UV-filtering laminated glass was applied outboard of the glass, allowing in natural light while mitigating solar-heat gain. A system of micro-vents in the stained glass panels also facilitates chilled interior air to cool the interstitial space. Local structural engineering firm Robert Silman Associates and the Museum of Modern Art's stained-glass conservator, Drew Anderson, developed a stainless-steel band in the shape of the tracery opening that, when installed between the stained glass and the perimeter glazing, is imperceptible and accommodates thermal expansion.

John Baer/Building Images
Workers install protective glazing outboard of the stained glass.
Murphy Burnham & Buttrick Workers install protective glazing outboard of the stained glass.
Restored stained glass rosettes and trefoils
Murphy Burnham & Buttrick Restored stained glass rosettes and trefoils
Stained glass
Emily Hooper Stained glass

Energy Upgrade

The cathedral’s east and west terraces are currently staging grounds for the drilling of geothermal wells approximately 2,200 feet deep—the height of the Empire State Building. Mary Burnham, AIA, a founding partner of MBB, says that St. Patrick’s will join a handful of religious projects that have drilled geothermal wells in Manhattan. “People with long-term views of their time here can see this as a sustainable option for the future,” she says. MBB’s analysis revealed that the initial cost of a conventional, ground-level cooling plant would approximate that of a geothermal system but with neither the subsequent 30-percent energy-cost savings, nor the annual carbon-emission reduction of 94,000 kilograms.

Project Management
High-definition monitors and a rewired audio system throughout the nave are just two of the technology upgrades at St. Patrick’s. Throughout construction, the project was managed with Autodesk BIM360. The 150 restoration specialists uploaded notes, progress photos, and project documentation for the cathedral’s 30,000 exterior and interior repairs to the cloud-based program via iPads. This workflow permitted real-time updates to the project team at large.

Courtesy Murphy Burnham & Buttrick

Note: This story has been updated since first publication.