WASHINGTON, May 18 (Reuters) - U.S. homebuilding fell more than expected in April, likely pulled down by soaring prices for lumber and other materials, but construction remains supported by an acute shortage of previously owned homes on the market. Housing starts tumbled 9.5% to a seasonally adjusted annual rate of 1.569 million units last month, the Commerce Department said on Tuesday. Data for March was revised lower to a rate of 1.733 million units, still the highest level since June 2006, from the previously reported 1.739 million units. Economists polled by Reuters had forecast starts falling to a rate of 1.710 million units in April. (Reporting By Lucia Mutikani; Editing by Andrew Heavens) Our Standards: The Thomson Reuters Trust Principles.