Icon of house with a crack down the middle of itFor single-family & duplex properties
For other properties, see Start Your Project
Updated:  03/23/2026

Earthquake retrofits entail bracing and bolting a home to its foundation. This project requires a building permit. To obtain the permit, you will either:

OR

  • Independently apply for a building permit by submitting an earthquake retrofit plan.  

Select the instructions that fit your project:

Retrofit Using Earthquake Brace & Bolt Program
Independent Earthquake Retrofit Project

How to Apply - Independent retrofit projects only

Use the fast, lower-cost Over the Counter Service if the project qualifies and you are using the Standard Plan Set A. Otherwise, use Standard Plan Review.

Over-the-Counter Service
Standard Plan Review Service

Inspections

You will be issued a Permit Card that lists required inspections. Schedule inspections at SJPermits.org or call 408-535-3555 for assistance.

Be ready — read Inspection Success.

  • The Permit Card must always be on-site and available to the Inspector. 
  • Have building plans and manufacturer instructions, if any, available to the Inspector.
  • Ensure there is access to all areas of the project work; provide a ladder if one is needed.

Questions?

We are here to help — visit, call, or email us. See Contacts sidebar.

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Learn more about earthquake retrofits

Understand the risk

 Bay Area map showing major fault lines with labels of probability of a major earthquake by 2030

Probability of a major earthquake 

Earthquakes are common in California. In the Bay Area, the probability of a major earthquake occurring with a magnitude greater than 6.7 between 2014 and 2043 is high — about 72%.

Source: Metropolitan Transportation Commission (MTC) data visualization.
https://bayareametro.github.io/Spatial-Analysis-Mapping-Projects/Project-Documentation/motm/2017_10/

 

 Side-by-side homes, the left one wasn't retrofitted and is tilted; the right one is retrofitted and is upright

What can happen to a home during an earthquake

On houses that are not bolted down, the lower cripple walls may buckle and collapse. The house can slide off the foundation or even overturn. Older wood-framed homes that are not built to modern-day earthquake standards are particularly at risk.

Understand how a retrofit helps

Foundation components

Earthquake - Foundation components photo

 

Strengthen the cripple walls 

A key area to strengthen are the cripple walls. Strengthening includes:

  1. Clip floor blocking to the top plate
  2. Place plywood (shear walls) over cripple wall
  3. Bolt/attach mudsill to the foundation

Transfer the earthquake force into the ground

See the schematic below for how the force moves through the elements of the retrofit and ultimately into the ground.

 Schematic of an underfloor area showing the bracing and bolting and the sequence of how an earthquake force will move through the parts and into the ground.

See also: Strengthening Your Home Against Potential Earthquake Damage 

Other items need attention, too!

Earthquake damage can also be caused by large, unsecured items. Go through your home to check that these items are all bolted to walls or otherwise secured:

  • Appliances
  • Chimneys
  • Furniture
  • Lighting fixtures
  • Wall hangings
  • Water heaters - California law requires that they are braced and strapped; see Water Heaters.