Why is the Valley expanding out, not up?

Valley 101 show

Summary: Why do home builders continue building out instead of up, and what's the deal with basements in the Valley? In this week's episode, producer Keith Reed speaks with experts about caliche, a hard surface deposit consisting of multiple compounds such as sodium nitrate and chloride, which hinders efforts to dig deep in the ground. The Valley 101 also met with a City of Phoenix official and a local architect about how efforts are being made toward building more high-rise residential buildings in downtown Phoenix.