Most Los Angeles property owners know their building has some kind of seismic risk. What they don't always know is which kind — and that distinction determines everything: the retrofit approach, the timeline, the cost, and in some cases, whether your building can be saved at all.
Two of the most common structural vulnerabilities in LA's older multifamily housing stock are soft-story conditions and non-ductile concrete (NDC) frames. They're often confused. They're not the same problem. And the fix for one won't touch the other.
Here's how to tell them apart — and what to do once you know.
What Is a Soft-Story Building?
A soft-story building is typically a wood-frame structure — often built between the 1950s and 1980s — where the ground floor is significantly weaker and more flexible than the floors above it. The classic example in LA is a two- to five-story apartment building with tuck-under parking. The open garage level has far less wall resistance than the living units stacked above it.
In an earthquake, the upper floors act like a heavy mass sitting on a weak base. The ground floor absorbs the energy it can't redistribute — and collapses. It's called a "pancake failure," and it's exactly as catastrophic as it sounds.
LA has been mandating soft-story retrofits since 2015 under the Soft-Story Retrofit Ordinance (LAMC 95.12). SKS Construction has completed 800+ of these retrofits since 2017. Cities including Burbank, Torrance, Culver City, Pasadena, and Glendale have active 2025–2026 compliance deadlines in force right now.
Signs your building may be soft-story:
What Is Non-Ductile Concrete?
Non-ductile concrete (NDC) buildings are a different animal entirely. These are reinforced concrete structures — often mid-rise or larger — built before modern seismic codes were adopted in the mid-1970s. The concrete is strong in compression, but the rebar detailing doesn't allow the structure to bend without breaking.
In a major seismic event, ductile structures absorb and dissipate energy through controlled deformation. Non-ductile concrete can't do that. The columns and beam-column joints are brittle — they crack and fail suddenly, with little warning. The 1994 Northridge earthquake collapsed several NDC structures in LA, and seismic engineers have flagged them as among the highest-risk buildings in Southern California.
The City of Los Angeles issued a non-ductile concrete ordinance (LAMC 95.22) requiring assessment and retrofit of these buildings. It's a longer, more complex, and more expensive process than soft-story work — involving structural engineering analysis, potential column jacketing, shear wall addition, or in some cases full demolition and rebuild.
Signs your building may be non-ductile concrete:
Why the Confusion Happens
Both vulnerabilities involve older LA buildings. Both carry mandatory compliance pressure. Both are life-safety issues. But the structural mechanics, the engineering solutions, and the contractor expertise required are completely different.
A soft-story retrofit typically involves steel moment frames or shear walls installed at the ground level — work SKS completes under a single design-build contract with in-house licensed engineering and city sign-off. The timeline is weeks to a few months, depending on unit count.
A non-ductile concrete retrofit is a larger-scale structural intervention that requires detailed analysis of every column, joint, and load path in the building. Timelines run longer. Costs run higher. The scope depends heavily on the building's original construction documents and the retrofit strategy chosen by the engineer of record.
The critical mistake: assuming a soft-story retrofit addresses your NDC exposure, or vice versa. They don't overlap.
How to Know Which One You Have
The fastest way is to check the year built and the construction type. Wood-frame buildings built in the 1960s and 70s with open ground floors are almost always soft-story candidates. Concrete buildings built before 1980 are potential NDC candidates.
If you've received a notice from the City of LA or another municipality, the ordinance number on the letter will tell you exactly which program applies.
If you haven't received a notice but you have concerns about your building, a licensed structural engineer can review your building's original plans and construction type and give you a definitive answer. SKS Construction provides FREE assessments for property owners who need clarity before making any decisions.
What SKS Construction Does
We are engineers who build. SKS has operated in Los Angeles for 39 years — since 1987 — under the same name, the same ownership, and the same fixed-price commitment. Every project comes with in-house licensed engineering, permit handling, and city sign-off under a single contract. No hand-offs. No subcontracted guesswork.
For soft-story work, we've completed 800+ retrofits across LA County and have active crews working under current city deadlines.
For structural retrofit and engineering assessment — including NDC evaluation, foundation work, CMU and URM retrofits — our in-house engineering team handles the analysis before a single scope of work is written.
80% of our clients are repeat clients. That number tells you more than any marketing claim.
Don't Wait on a Deadline You Already Have
If your building is in Burbank, Torrance, Culver City, Pasadena, or Glendale — the clock is already running. Missing a retrofit deadline doesn't pause the ordinance; it adds fines, accelerates the timeline, and in some cases triggers city-ordered vacancies.
Call SKS Construction at (818) 855-1181 or email info@sksconstruction.com for a FREE structural assessment. We'll tell you exactly what you have, what's required, and what it will cost — before you commit to anything.
SKS Construction | Design | Engineer | Build | Since 1987 (818) 855-1181 | info@sksconstruction.com
info@sksconstruction.comCA CSLB License #AB720390(818) 855-1181