Unreinforced masonry chimney may collapse, striking occupants below or damaging roof and other structural elements supporting the building. In California, older brick chimneys — generally those built before 1980 — are too stiff and brittle to withstand major shaking. The mortar holding them together can be ground down.
There are many recommendations for this, one that includes retrofitting and actually bracing the chimney. That is if you would like to completely eliminate the option of getting rid of the chimney, which would be the best option. If as a home owner you don’t need the chimney to be functional, the retrofitting could be as simple as placing a steel tube down the structure and filling it with concrete.
There is also the option of removing unreinforced masonry chimneys and replaced with an approved chimney with metal flue. Building built before 1960 may have unreinforced masonry chimneys. Home owners may want to consult a qualified architect or structural engineer for seismic requirements.
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