In the Cambridge, Mass., house, contractor Tom Silva jacks up joists to make a floor level with an addition, while outside, landscape architect Gregory Lombardi unveils his front-yard plan. Meanwhile, host Kevin O'Connor and carpenter Norm Abram visit neighborhood stores; and O'Connor tours the nearby Henry Wadsworth Longfellow House. Projects on “Ask This Old House” include a flat wheelbarrow tire, a broken rain gutter and a leaky water-heater valve. Also: drilling holes in ceramic tiles.