Traditional horizontal lap siding goes by many names. It's known as clapboard siding in much of the East and as bevel siding elsewhere. Whatever you call it, it is one of the most popular and durable exterior building materials. Indeed, you'll find it in excellent condition on American homes more than 250 years old. Though long-lived, wood siding isn't all that tough. That's because it's usually milled from cedar, redwood or pine - softwood species that are easily cracked or gouged if struck by a ladder, falling tree branch or line drive. Another common problem: The boards tend to split if nailed too close to the end or edge, or if too many nails are used. This type of siding requires ongoing maintenance and your inspector will be checking carefully to see if the siding has been properly maintained.