Vent an Island Sink…and Other Tricky Spots
A handy one-way valve installed below in the counter can solve a venting challenge and simplify plumbing design
Synopsis: Putting a sink in a kitchen island used to mean running a complicated vent loop up, down, and under the floor until the line ultimately could be vented through the roof. Enter the air admittance valve (AAV). This handy gadget is a one-way valve that allows air to enter the drain line when the sink is drained while preventing sewer gases from entering the home. Lynn Underwood, a building official in Norfolk, Virginia, gives the pros and cons of AAVs. You’ll learn where you can use them, how to install them, and how to convince your building inspector if he or she is dubious.
Adding a sink or a dishwasher to a kitchen island isn’t quite as simple as just tapping into the water supply and the drain line. You also need to vent the drain line (usually through the roof) to keep water in the sink trap.…