The first thing people notice is that their doors, windows or deadbolts are hard to open and close. Sometimes homeowners spot their foundations pulling away from exterior walls. Sometimes they hear a noise that sounds like a gunshot. All are clues to big problems caused by the drought: damage to foundations, basements and walls. The gunshot sound comes from a cracking foundation. The other symptoms indicate that shrinking dry soil is making foundations, porches and concrete slabs settle. Beneath them, big gaps can open up under a house. Today, a crew from Helitech, which does structural repair in five states, is shoring up the foundation and porch of a home in a subdivision here.