Plot: Ask This Old House welcomes landscape contractor, Lee Gilliam to the cast and shines a spotlight on his 30 years of experience; Richard Trethewey helps a homeowner repair a leaking 3-valve shower while retaining the bathrooms original 1930's tile; Lee and Jenn Nawada work together to refresh a homeowner's eroding sloped yard; removing excess mulch, and installing boulders and ground cover plants.