July 31, 2026

Opinion: Office conversions require more structural scrutiny

Two steel columns buckled on the 21st floor of a 37-story Manhattan office tower undergoing conversion into apartments on Jul. 7. Cracks prompted officials to evacuate the site and nearby buildings. The cause at the former Pfizer headquarters remains under investigation, but the incident has sharpened a question for California developers: What must be verified before an aging commercial building can be safely and economically converted into housing?

That discussion is especially timely in Los Angeles. The Citywide Adaptive Reuse Ordinance took effect Feb. 1, extending streamlined conversion rules to commercial buildings at least 15 years old, and qualifying parking structures at least five years old.

Mayor Karen Bass has said the expansion could spur more than 43,000 housing units. Greater Los Angeles office vacancy also reached 25.6% in the second quarter of 2026.

Tourjé

Adaptive reuse is a powerful way to create housing, but developers cannot necessarily assume an eligible building is structurally ready for conversion right off the bat. Offices, retail buildings, and parking structures were designed and originally constructed for different uses, loads, and seismic demands. Some may adapt with limited intervention. Others require substantial work. Knowing the difference can determine whether a project is viable, or not.

NEW USE CHANGES BUILDING EVALUATION

Los Angeles' ordinance can streamline the approval of a qualifying conversion, but it does not remove the structural and life-safety requirements the building could require, or hazards that the building may already have. Changing an office or another commercial property into housing requires project teams to evaluate how the proposed layouts, structural modifications, mechanical, electrical and plumbing systems, and new occupancy will interact with the existing structure.

California's 2025 Building Standards Code took effect Jan. 1. Depending on the project scope, existing conditions, and applicable compliance pathway, a conversion may require upgrades to the systems that resist earthquake forces, foundations, structural connections, or floor and roof diaphragms, which distribute lateral forces throughout the structure. The condition of an associated parking structure may also affect the project.

The extent of that work can determine whether the development is still a targeted conversion or becomes a much larger reconstruction or repair effort. Seismic strengthening or major structural repairs are often one of the largest structural cost drivers in a California or West Coast adaptive reuse project. Developers need to understand what the building requires before they commit to a design, budget, and schedule.

HIDDEN CONDITIONS CAN REWRITE BUDGET

Major cost overruns often trace back to conditions that are not visible during a walkthrough or even limited exploration of a building to attempt to detect unforeseen conditions. Concealed foundation deficiencies, deteriorated steel, inadequate seismic connections, prior substandard repairs or alterations, and water-related damage may not surface until demolition or more involved, targeted investigation begins.

The Urban Land Institute has reported industry estimates that only about 25% to 30% of existing office buildings may be viable for residential conversion. Structural conditions are only part of that calculation. Floor-plate dimensions, building systems, location, acquisition costs, and financing can also determine whether a project is feasible.

Original drawings do not always show what was actually built, and more importantly, they do not capture decades of renovations that were permitted or nonconforming structural repairs, structural distress, and deterioration that may exist. Targeted exploratory work lets the team verify critical conditions early. Sometimes it shows that planned strengthening is not necessary. Other times, it finds hidden deficiencies before they cause delays—or what most developers fear: the unexpected change order.

STRUCTURAL DUE DILIGENCE BEFORE DESIGN

It is recommended to bring structural engineering and construction expertise into the earliest feasibility and acquisition stages, ideally before a property is purchased or financing is finalized or immediately following acquisition. Early investigation allows the project team to compare original plans with existing conditions, conduct exploratory testing, estimate structural upgrade costs, and determine whether the proposed residential program is preliminarily achievable and viable before major design work begins.

Los Angeles' original adaptive reuse program helped create more than 12,000 housing units downtown. The lesson is not that adaptive reuse is unsafe or unworkable. It is that zoning eligibility is only the beginning of determining whether a particular building can support a successful conversion.

Early structural evaluations are one of the most valuable investments a project team can make. It reduces uncertainty and gives owners facts before they commit significant time and funds.

The goal is not to stop a conversion. It is to make sure the project starts with a realistic understanding of the building and limiting surprises during the conversion process.

Kyle Tourjé is executive vice president at Alpha Structural, overseeing all engineering and construction operations across four offices throughout Southern California. Alpha Structural had more than 30 years of experience in foundation repair, hillside stabilization and seismic retrofitting.