Home prices in the 20 metro markets surveyed by the S&P Case-Shiller home-price indexes were up in July from June by 1.6 percent, which is believed to be a sign that there’s finally a floor under the U.S. housing market, especially since it’s the third monthly increase in row. The floor is in the basement, since prices are still 13.3 percent lower than in July 2008, and roughly at the same levels as in 2003.