Grading; Inside Walls; Bathtub Stopper Ask This Old House : Season 6 Episode 12

Landscape contractor Roger Cook shows host Kevin O'Connor several different ways to determine the grade, or pitch, of a landscape. Then, back in the loft, Roger and Kevin, along with general contractor Tom Silva and plumbing and heating expert Richard Trethewey ask, "What is it?" Then, Tom and Richard show Kevin different ways to "see" what's inside a wall. Finally, Richard helps a homeowner repair a bathtub that won't hold water.