Excavation begins on a new kitchen foundation for the Winchester, Mass., house. Also: the master-bedroom layout is unveiled by architect Donald Stirling; and host Steve Thomas and homeowner Kim Whittemore tour a nearby greenhouse with landscaper Roger Cook. On “Ask This Old House”: Thomas and contractor Tom Silva demonstrate floor sanders and caulking techniques. In the “house call” segment, plumbing expert Richard Trethewey replaces a corroded pipe in a Pittsburgh home.