General contractor Tom Silva helps a homeowner clean, stain and seal his mahogany backyard deck. Then Tom, along with host Kevin O'Connor, plumbing and heating expert Richard Trethewey and landscape contractor Roger Cook ask, "What is it?" Kevin makes a House call to Chicago to help a homeowner prevent sewage backup in her basement by replacing her flood control system. In the Ask This Old House loft, Tom and Richard share a viewer tip on how to remove a wood plug from a hole saw.