While very attractive, clay and concrete roofs are up to 10x heavier than the asphalt tile or metal panels. It would take a laterally house to support them in an earthquake.

How do you know if it is?

The most telling sign, regardless of when or by whom the house was built, is the the amount of full height wall under it, at each level. If and wall line has more linear feet of window and door openings than wall, there is likely weakness. Typically, the sides of the house are stronger than the front and rear walls because have fewer openings.

The number of interior walls on the main floor is another influence. If is largely open concept design, that floor won’t have the strength of one with walls defining various spaces by function. Also, how many floors are supporting the roof.

The big question is can the perimeter walls be strengthened enough to support the roof. There have been instances where it made more sense to replace the tiles with lighter ones.