Plumbing and heating expert Richard Trethewey examines a viewer's corroded copper pipes and identifies the source of the corrosion: a rusty hot water heater. Back in the loft, Richard, general contractor Tom Silva, landscape contractor Roger Cook and host Kevin O'Connor try to identify unfamiliar objects in the "What is it?" segment. Then Tom helps a homeowner replace the worn-out weather stripping around his drafty kitchen door.