I'm considering to buy an old house built in 1920s - victorian. I plan to live in it. It has brick foundation and at some point the brick was topped/covered with concrete (process called "saddling")

Now in order to properly quote the offer, I need to understand how much work needs to be done on the foundation. Basically changing the brick foundation to concrete foundation.

I'm sure it is a case by case analysis but I wanted a range just to give me a ballpark on the cost of foundation rehab for the property.

Property info:

Area 2100 sq feet, duplex,

unit 1 (upper unit): 3 bed 1 bath

unit 2 (lower unit): 2 bed 1 bath

The property is in North California. Any pointers, websites, estimation-techniques,  estimate numbers, blogs, suggestions or personal experience,  that is shared is highly appreciated.

Thank you.