Navigating New Building Code Regulations for 2026

Change is coming.

The new 2025 California Building Code (CBC) takes effect in January 2026. Though it was supposed to be released in mid-2024, it isn’t available yet. We already know what the changes will consist of since they will be based on the already-adopted American Society of Civil Engineers (ASCE) 7-22. Regardless, any building permit applications submitted on or after January 1, 2026, will have to comply with the 2025 CBC. 

Inland Foundation Engineering is already ramping up work on projects that will be designed under the new CBC. We are studying and learning the nuances of the new code and its effect on our clients’ projects.  

What do we know now?

The new site classification procedure for seismic design appears to be the primary code change that will affect our geotechnical work.  Currently, the 2022 CBC allows three alternative methods to determine site class. The new regulations (2025 CBC) only allow one, the shear wave velocity (Vₛ) method. The other methods, Standard Penetration Test (N) and undrained shear strength (Su) have no physical meaning and their relationship to soil stiffness is questionable. Vₛ is the preferred method since it is directly related to soil stiffness and the soil’s ability to resist deformation under seismic shear stress. In addition, the 2022 CBC includes five different site classifications; the 2025 CBC includes eight, depending on the average Vₛ in the upper 100 feet.  

Where Vₛ data is unavailable, the 2025 CBC allows it to be estimated. However, depending on the correlation used, an additional factor of 1.3 may have to be applied to the estimated Vₛ for site class determination.

There are additional changes, but the main focus for IFE will be the way we characterize the project’s site soil conditions with respect to how they’ll respond during an earthquake.

How Does This Impact Our Clients?

Simply put, it’s our goal to make sure that it doesn’t. Conversations are starting about project scheduling and whether they’ll fall under the new code or not. Regardless, if we do our job in the best way, there shouldn’t be any issues. 

The focus on Vₛ for site classification should not significantly affect our fees since we already use Vₛ now for site-specific seismic studies of larger projects. There will be a period of time to figure out the size of a project that economically dictates when direct measuring of Vₛ is warranted and where estimation will suffice.

The code changes should drive early discussions between the project's structural and geotechnical engineers regarding the most economical approach to site classification and foundation design. In the long run, this will provide project owners with improved design efficiency and reduced costs.

How Does This Affect IFE?

IFE is taking these changes in stride. When you love what you do and work with a great group, that’s a good problem to have. No matter the size of the change, we’re simply doing what we do ahead of any type of update to our industry. We’re paying attention, and whether the changes coming are big or small, we’ll prepare for them in the best way possible because our clients deserve that.

Constant Learning is Key.

Yes, there’s plenty of time to prepare. We look at that as an opportunity to get ahead of the game. At IFE, our clients trust us to be the experts who are mindful of their time and budget. The reality is that many clients don’t know about these new regulations, and IFE takes pride in making sure they don’t have to. 

Now We Wait.

In the meantime, IFE will continue to utilize and develop our expertise to achieve our main goals of saving clients time and money. Change is good. We’re lucky to be in an industry that prioritizes constant development, and we take pride in doing the same in return.