Work on the new foundation for the 1849 Carlisle, Mass., farmstead is the focus as contractor Tom Silva fashions a crushed-stone foundation footing and carpenter Norm Abram oversees the installation of the foundation itself, a precast unit. Meanwhile, arborist Matt Foti and landscaper Roger Cook discuss how to move the septic tank without harming a catalpa tree; and host Kevin O'Connor visits Carlisle's Brook Farm State Park, a working dairy farm. On “Ask This Old House,” projects include removing bolts and screws with stripped or damaged heads; making an edge for a concrete walkway using large cobblestones; and jacking up a porch roof to repair a rotting post.