Ask This Old House plumbing and heating expert Richard Trethewey helps a homeowner replace the shutoff valve underneath her kitchen sink. SUBSCRIBE to This Old House: http://bit.ly/SubscribeThisOldHouse Time: 1-2 hours Cost: $30 Skill Level: Moderate Tools List for Rebuilding a Shut Off Valve: Wrench Screwdriver Shopping List: Valve stem repair kit Steps: 1. Shut the…