Replacing rotted stairs; leaky polybutylene pipes

Landscape contractor Roger Cook replaces a set of rotted wooden stairs with new steps made of granite. In the ASK THIS OLD HOUSE loft, Roger, host Kevin O'Connor, general contractor Tom Silva and plumbing and heating expert Richard Trethewey ask, "What is it?" Richard travels to Raleigh, North Carolina, to help a homeowner replace leaky polybutylene pipes throughout his house. (ATOH #622, 3/1/08, 1400-1430)