Inside the loft, Richard gives Kevin some lessons on leaky valves and how to repair them. Then, Tom heads to Waltham, Massachusetts to help homeowners David Anderson and Alica Beneteau replace an old, rusty cellar door with a new fiberglass model. Back in the loft, Tom, Richard, Roger and Kevin ask, "What Is It?" Then, Roger helps homeowner Christine Dinardo of Carlisle, Massachusetts repair a leaky drip irrigation hose.