Fireplaces, Heating Stoves, Flues and Chimneys - What flue liner system is best?

We own a home that has a fireplace in the living room and another fp directly above in the master bedroom on the 2nd floor. These are the original fireplace/chimneys from when the house was built in 1927. Neither of them have a flue liner in place. It has been recommended that we install either a stainless steel or cast-in-place system. I understood the cast-in-place system provides the chimney with additional structural support that the stainless steel system does not. We live in Northern CA, earthquake country, and we would like to make the right decision on this upgrade. Even if one costs more than the other.
Thank you for any advice/information you may have to share. :confused:

I would opt for the cast in place flue liner. They have been around a long time.

A chimney normally has little reinforcement and the additional stiffness and bonding could maintain structural integrity. Even a small quake can cause minor damage to the chimney with the real problem coming from the damage to the traditionally light roofs in your area if brick are dislodged.

You may have a reinforced chimney and not know it, but a liner would be good insurance.

Dick