paul galvin: it was built to house levi strauss's blue jean assembly plant back in 1906. jessica: before the school moved in, it had to do a massive retrofit. paul: basically put the entire building, 82,000 square feet, on stilts and lifted it up off of its then foundation. jessica: everything inside this old building is basically new. paul: you see a lot of steel everywhere. you'll see these huge steel i-beams that are holding up the building, in addition to the original foundation, and preparing it to withstand an earthquake. jessica: an earthquake no one wants to experience, but everyone knows is coming. simin naaseh: it may not happen tomorrow, may happen, you know, the next day or 15 years from now, but we know that it will happen. jessica: as part of san francisco's ongoing effort to reduce risk, the city has put in place the first law of its kind in california. private schools have to evaluate seismic safety. patrick otellini: at first, people realized that they're a little shocked that this isn't already required. jessica: public schools have been regulated since t