Across the country, aging buildings face a growing need for upgrades, not just to meet modern design expectations but to protect occupants from natural disasters. Nowhere is that more critical than in regions prone to seismic activity.
From Los Angeles and Seattle to Salt Lake City and Memphis, building owners are rethinking how they approach seismic retrofitting and tenant improvements (TIs). When done together, these upgrades create safer, more resilient environments that retain tenants and preserve long-term value.
What Are the Stakes?
Seismic risk isn’t limited to the West Coast. According to the U.S. Geological Survey, 37 U.S. states have experienced earthquakes exceeding magnitude 5 over the past 200 years.
In California alone, the likelihood of a magnitude 6.7 or larger quake within the next 30 years is close to 99%. But significant risk also exists in places like Utah’s Wasatch Front, the Pacific Northwest’s Cascadia Subduction Zone, and even the central U.S., where the New Madrid Seismic Zone spans multiple states.
Rami Tawasha, a structural engineering consultant, explains: “When owners think of seismic work, they often picture only the skeleton of the building. In reality, it’s about the whole ecosystem, including structure, systems, and tenants’ ability to get back to business quickly.”
Codes and Standards That Shape Retrofit Projects
Seismic retrofitting is heavily shaped by national and state-level codes. The ASCE 41-23 standard outlines a three-tier approach to evaluating and upgrading existing buildings, with performance objectives ranging from basic life safety to full functional recovery. Many jurisdictions, especially those adopting the International Existing Building Code (IEBC), trigger seismic requirements when owners pursue significant alterations, occupancy changes, or additions.
States like California, Oregon, and Utah have introduced their own amendments or mandates aimed at improving seismic resilience. Some cities, including Los Angeles, Seattle, and Salt Lake City, require seismic upgrades for specific high-risk building types, such as soft-story apartments or unreinforced masonry (URM).
A Phased Approach to Delivery
Retrofits and TIs can be disruptive, but they don’t have to be. A structured, integrated delivery process ensures smoother outcomes and stronger returns.
Here’s how most successful projects unfold:
1. Risk Screening and Project Goals
Rapid assessments (e.g., Tier 1 screenings under ASCE 41) identify vulnerabilities and clarify the owner’s performance priorities. The U.S. Resiliency Council (USRC) rating system is sometimes used to communicate expected safety, repair cost, and downtime.
2. Detailed Design and Cost Modeling
For complex projects, nonlinear analysis and FEMA P-58 modeling help forecast potential quake impacts in terms of casualties, repair costs, and business interruption. This step supports clear decision-making.
3. Integrated Retrofit + TI Planning
Bundling retrofits with tenant improvements reduces duplicate work and aligns permitting schedules. This is an ideal time to add energy code upgrades, accessibility enhancements, and MEP system replacements.
4. Construction and Phasing
With clear sequencing and strong contractor coordination, buildings can remain occupied during work. Noise controls, weekend shifts, and swing spaces keep tenants functional throughout.
Rami Tawasha puts it this way: “The best outcomes come when structural engineers and tenant improvement teams sit at the same table from day one. It prevents costly rework and ensures the final space performs as well as it looks.”
Smart Strategies for Structural and Nonstructural Resilience
Different building types require different retrofit solutions. For example:
- Shear walls and diaphragm strengthening are cost-effective for soft-story or tilt-up structures.
- Steel moment frames allow for open floor plans with minimal tenant disruption.
- Base isolation or supplemental damping systems are best suited for facilities needing high-level protection, such as hospitals or data centers.
But not all damage comes from the structure itself. Nonstructural elements like ceilings, piping, and rooftop units account for nearly 50% of total earthquake-related building losses. When tenant improvements are underway, it’s the perfect time to:
- Add bracing to suspended ceilings and partitions
- Anchor mechanical and electrical equipment
- Install flexible connections on fire sprinklers and plumbing
Cost Context and Market Trends
Tenant improvement costs continue to rise. According to JLL’s 2025 U.S. Fit-Out Guide, the average mid-quality office fit-out now runs about $280 per square foot. Cushman & Wakefield places top-market costs between $212 and $219 per square foot, depending on location. Retail interiors come in slightly lower, averaging $147 per square foot.
With costs trending up, many owners see the value in bundling retrofits and TIs into a single, coordinated effort. Doing so reduces mobilization fees, shortens project timelines, and avoids reopening finished areas. As tenant expectations shift toward energy-efficient and resilient workplaces, delivering those features up front helps attract and retain long-term leases.
Why It Pays to Build Resilience
The business case for seismic upgrades is strong. The National Institute of Building Sciences (NIBS) reports that every $1 invested in seismic retrofitting saves about $4 in future losses. And for jurisdictions that adopt modern seismic codes, the community-wide savings rise to $11 per $1 spent.
The cost of downtime also matters. Even a structurally sound building can be offline for weeks or months if nonstructural damage isn’t addressed. Tools like FEMA P-58 allow owners to compare upgrade options based on repair time and financial exposure—not just capital expenditure.
Policy Examples Across the U.S.
Local seismic ordinances continue to expand. For example:
- Los Angeles mandates retrofits for soft-story buildings and non-ductile concrete structures, affecting over 12,000 properties.
- Portland, OR, is advancing retrofit requirements for unreinforced masonry buildings, prioritizing schools and emergency shelters.
- Salt Lake City introduced incentives for voluntary seismic upgrades on vulnerable housing stock.
- Seattle maintains a URM inventory and is moving toward mandatory retrofit requirements within the next few years.
Final Thoughts
Seismic retrofitting and tenant improvements are no longer two separate initiatives. For forward-looking property owners, they represent a single opportunity to deliver safety, performance, and modern design without compromise. Whether required by code or driven by market demand, retrofitting is most successful when it’s paired with thoughtful interior upgrades.
The risk is real across much of the U.S., but so are the tools. ASCE 41-23, FEMA P-58, USRC ratings, and local building codes now make it easier than ever to plan, communicate, and execute retrofit strategies that deliver long-term value. As natural hazards grow more frequent and tenant expectations rise, the path to excellence lies in integration.