Grace Cathedral

The Challenge

Grace Cathedral is one of San Francisco’s most iconic landmarks. The Cathedral’s aging infrastructure presented a complex, multi-faceted waterproofing challenge rooted in the cathedral’s original mid-20th-century concrete construction.

Deteriorating concrete and decades of exposure to San Francisco’s coastal climate caused progressive spalling of the cathedral’s exterior concrete surfaces, exposing the underlying structure to further moisture intrusion. Moisture penetration had corroded the reinforcing steel embedded within the concrete, accelerating structural degradation and demanding urgent remediation. Additionally, the original and previously replaced roofing assemblies had reached or exceeded their serviceable lifespans, generating active leaks and threatening the building’s interior.

Our Solution

Fidelity Roof Company designed a phased commercial roofing and waterproofing program built for the long term, prioritizing systems with a target service life of 30 years or more to reduce re-roofing frequency and lower total ownership costs for the property. Across approximately 150,000 square feet of roofing and exterior surfaces at this San Francisco historic landmark, Fidelity deployed a multi-system approach matched to each area’s specific conditions: modified bitumen and metal roofing across primary roof fields for proven weather resistance; roof coating and restoration where existing assemblies retained value, avoiding unnecessary tear-off; urethane traffic-bearing membranes at accessible decks and pedestrian plaza surfaces for durable waterproofing under foot traffic; exterior concrete wall waterproofing and protective coatings to stop the progression of spalling and rebar corrosion; and green roof elements where site conditions allowed, supporting the cathedral’s sustainability objectives. Major project phases were planned up to one year in advance, with all roofing work, deliveries, and construction activity coordinated around Grace Cathedral’s programming calendar—ensuring services, events, and community use continued without interruption throughout.

Project Execution

Executing roofing and waterproofing work at a continuously operating, high-profile public venue required exceptional logistical discipline and site awareness. Additionally, the historic preservation standards in place for any repair or replacement solution had to respect the cathedral’s architectural integrity and meet the expectations of a nationally recognized historic landmark.

Work was sequenced in carefully defined phases across individual roof sections and façade areas, keeping the active footprint of construction contained at all times and allowing the remainder of the cathedral to remain fully operational. Material deliveries, crane lifts, and high-noise activities were coordinated directly with Grace Cathedral’s event programming—with work windows confirmed weeks or months in advance to align with the facility’s schedule of services.

On site, Fidelity’s crews maintained the strict housekeeping and containment standards required at a landmark San Francisco property open to the public, safeguarding irreplaceable interior finishes, furnishings, and historic artwork throughout the duration of each project phase. Where multiple commercial roofing systems were installed across a single complex structure, precise detailing at all transitions, penetrations, and assembly interfaces ensured watertight performance and long-term durability. Between planned project phases, Fidelity’s established role as a long-term roofing partner has included emergency leak response—providing rapid intervention to protect the structure and its contents whenever urgent issues have arisen.

The Results

The result: a trusted roofing and waterproofing partnership now spanning more than 26 years.

Spalling concrete and rebar corrosion have been addressed through comprehensive waterproofing interventions, halting the cycle of moisture-driven deterioration. Roofing and waterproofing systems selected for 30+ year service life continue to perform, reducing the frequency and cost of major interventions over time.

Through careful pre-planning and close coordination with cathedral staff, all project phases were completed without interrupting a single scheduled service, event, or community program. The client continues to rely on Fidelity Roof for roofing repair, restoration, and emergency response, ensuring San Francisco’s third-largest Episcopal cathedral remains structurally sound and weathertight, safeguarding its irreplaceable architectural and cultural legacy for future generations.