Ask This Old House kicks off its 7th season on PBS. General contractor Tom Silva prevents a garage roof from collapsing by replacing a rotting support post. Then Tom, along with host Kevin O'Connor, landscaping contractor Roger Cook and plumbing and ... (more)heating expert Richard Trethewey ask, "What is it?" Then, Roger helps two homeowners dry out their basement by installing a dry well to handle discharge from their sump pump.