St. Ignatius Church Restoration

One of the unknown perks of working for DHC in the niche world of construction engineering is getting the chance to work on some of the most iconic and historic structures throughout the country. One such opportunity came up during the restoration of the façade of the St. Ignatius Church, in San Francisco, CA. Built in 1914, St. Ignatius is one of the city’s largest churches, made even more striking with two commanding spires accentuating it’s classic Italian Renaissance and Baroque architecture.

It was the restoration of this modern-day basilica that led to DHC, partnered with Scaffold Solutions, being charged with providing a fully netted worker access solution. Workers needed easy access to the façade around the entire perimeter of the church, including it’s 140’-tall bell tower, the iconic basilica dome, as well as the two imposing spires.

Considering the church would remain in service to the community throughout the restoration process, the first challenge was maintaining the public’s access through the southern doors. Utilizing the natural flow of the church’s architecture, this was accomplished by strategically setting scaffold posts in line with the entrance columns and using long-span trusses over the doors to keep the pedestrian flow clear. However, the real challenge would be getting workers in and around the two tall spires. Rising 216’ above street level, the spires flanked the grand southern entrance to the church’s nave. Not only would the scaffold have significant height, but a critical design consideration was also the strength of the structure itself. With over a century of history already weighing heavy on the structure, limiting additional scaffold load was a key objective.

To accomplish this, careful consideration was paid to making the layout of the scaffold as efficient as possible. For the lower ~100 ft of scaffold around the spires, scaffold was set on the ground and installed tight to the square footprint of the spire bases. Where possible, the scaffold was reset onto the nave low roof. Where the spire silhouette changed from rectangular to cylindrical, 24’-long trusses were used, attached to cardinal full height scaffold towers. This significantly lightened the overall scaffold structure while maintaining the workers’ ability to remain within arm’s reach of the structure’s facade.

To ensure the lateral stability of the fully netted scaffold, yoke ties were employed to secure the scaffold to the main spire structure. Due to restoration of the façade being the reason for the scaffold installation, invasive and destructive installation of anchors was not an option. By strategically placing yoke ties around the upper columns and structural steel of the spires, a rigid tie that stabilized the scaffold in the event of high winds could be installed without any permanent impacts. 3D models of the spire scaffold were used to space out the ties as much as possible and determine the right balance between stability and efficiency.

Close coordination and clear communication with the scaffold contractor and the general contractor throughout the design process ensured everyone was on the same page and paved the way for a smooth and successful project!