Now that you have your stationary kitchen island or butcher block island with customized sink built to your ideal form and style, you have that tricky task of figuring out how to hook up all the right tubes to the right holes. If you don't want to hire a contract plumber to do the work for you, you have to understand that completing the project yourself will not necessarily be an easy time. However, it can be truly rewarding once you finish and know that the giant of a task presented to you was tackled with the best efforts and hopefully results.
The reason that kitchen island plumbing presents such a unique problem is the fact that islands are located in the middle of the room. For regular kitchen sinks, which are adjacent to the wall, they have a pipe within the wall that connects to a vent outside which provides the essential supply of air to keep equal pressure in the system. Kitchen islands, however, are detached from any drains and vents. How exactly do you hook up a sink when there is no hole to hook it up to? Well, you know that you can't run the vent straight up towards and through the ceiling of the kitchen. Instead, you can use the drain pipe as a vent in a "loop vent". Most plumbers actually recommend this alternative because it loops as high as it can go inside the cabinet before going under the floor and over to the main vent in the wall. The horizontal drain that is located beneath the floor is only filled half-way with water and the top loop of the vent can allow air to flow back into the drain. This prevents those undesirable gurgling sounds and stuffed-up sink.
As a second viable option that requires no above-ground venting and therefore makes installation easier, you can use an AAV (air admittance valve). These units are gravity-operated valves that open when the water creates negative pressure. Allowing the air to enter equalizes the pressure. Whichever method you choose, we hope you enjoy the luxury of a wood or stone kitchen island for years to come with the right plumbing!