California State Capitol Infrastructure Upgrades
Supporting updates and repairs as the architect of record
Encompassing 482,000 square feet, the California State Capitol stands as the center of decision-making for the country’s most populous state. Originally built from 1860 to 1874, the building has undergone many changes through the years to accommodate evolving needs, including the addition of the first annex, referred to as the East Wing, in the early 1950s.
The Treanor Historic Preservation team began working as the architect of record for the state capitol building in the late 1990s and served in that role for almost two decades. Our work spanned many historic preservation projects, infrastructure updates, accessibility studies, and significant repairs to the South Portico at the West Wing.
Repairing the damaged South Portico
In 2001, a semi-truck slammed into the state capitol’s South Portico. The impact caused significant damage to the portico’s entry. Along with structural damage, the truck caught on fire, causing further destruction.
At the time of the incident, Treanor was serving as the architect of record for the West Wing repainting project, and promptly shifted gears to support the fast-tracked portico repair project as the design-build team’s master architect. We started by assessing the extent of the damage.
The South Portico required significant repairs. The portico’s granite structures needed examination to see what could be repaired and if any stones needed replacement. We documented the granite’s condition and prepared repair plans, which included composite patching, cleaning, and replacement recommendations.
The fire had also scorched many exterior surfaces, which needed repainting. We worked closely with the contractors to ensure the South Portico’s exterior was restored and addressed any challenges that came up during the $12.5-million rebuilding process.
The capitol building’s historic interior also suffered damage. The stones for the portico’s granite stairwell needed inspection, which uncovered damage caused by the impact and issues from years of use. Some stones were turned around, and others were replaced, with our team working to preserve and reuse the materials for this phase of the project. Our work on the South Portico received a Preservation Design Award from the California Preservation Foundation in 2002.
Treanor restarted the West Wing repainting project and completed it later that same year.
Updating critical state house infrastructure
Given the California State Capitol’s age, the building required many repair and upgrade projects over the years. As the on-call architect for the State Capitol for almost two decades, our team led several phases of critical work that made sure the historic space met modern needs and that the work of governing could continue to function, culminating in $15 million in updates.
The building had been renovated several times, with one of the most significant renovations in 1954, with the addition of the East Wing. We worked closely with the Capitol’s facilities team on multiple projects to update critical systems in both wings and maintain the complex’s overall historic significance. We improved many building systems, from fan rooms and electrical upgrades to seismic improvements and envelope restoration, and addressed preservation-specific projects such as the historic exterior pillar relocation at the West entry.
We also conducted life-safety, security, and accessibility studies and completed several projects to improve universal access, including projects such as handrail alterations in the Assembly chamber. Two lifts were also installed to provide better access, and a third was designed. Project designs were completed for accessibility upgrades to restrooms, elevators, and the path of travel. In addition to our team coordinating numerous mechanical, electrical, and plumbing upgrade projects, we also designed and provided construction support for the sixth-floor café, basement coffee shop, basement cafeteria, commercial kitchen, and dining room.
Working in a state capitol is always memorable. Supporting important updates and repairs at the California State Capitol is something our team was honored to do working in both the original West Wing and the East Wing annex while it was in existence. The wing was demolished in 2023 to make way for a new addition to the capitol.





