Ask Me Help Desk - Kitchen sink air vent in DUMB SPOT!

Our kitchen sink is on an island and behind the sink was a small countertop (bar) about 8" higher than the sink. We have new countertops that we'd like to install but want everything at the same countertop level (no bar) which means we either need a new air vent below the sink, or a very beautiful pipe that sticks out the top of our counters and extends to the wall! Can we:
A) lower the pipe to be the same level as the sink?
B) seriously, replace just that part of the pvc with a nice metal pipe that really does extend across the countertop to the wall (our kitchen is stainless/industrial style so it would be okay).

Help! And Thanks! :confused:

Quote:

Originally Posted by perduehouse

Our kitchen sink is on an island and behind the sink was a small countertop (bar) about 8" higher than the sink. We have new countertops that we'd like to install but want everything at the same countertop level (no bar) which means we either need a new air vent below the sink, or a very beautiful pipe that sticks out the top of our counters and extends to the wall! Can we:
A) lower the pipe to be the same level as the sink?
B) seriously, replace just that part of the pvc with a nice metal pipe that really does extend across the countertop to the wall (our kitchen is stainless/industrial style so it would be okay).

Help! and Thanks! :confused:

First off, I'm NOT a licensed plumber...

But I think your question/solution isn't that hard.

First off, if it's a "true" island, there are no walls around to vent to. In this case, you can either use a loop-vent (OK with UPC and IPC, depending on exactly how you design it, with 90deg or 45deg joints), or an Air Admittance Valve (AAV), sometimes called a "cheater valve"

See this link for pretty good pics of both:
Plumbing An Island Sink

Rollover the thumbnails in this link to see the various ways to do it:
Vent an Island Sink and Other Tricky Spots

BUT.. from your description, it sounds like the current sink is already vented to a vertical vent pipe inside the wall. If that's the case, there should be no problem in simply attaching to that vertical vent stack a few inches lower, if it's accessible.

IF you want to go industrial, large-diameter DWV (drain-waste-vent) copper is available. It's expensive but you won't need a lot of it, and it could be very pretty in an industrial sort of way. There aren't a lot of good pics around of copper DWV, since it's expensive and not used a whole lot anymore, except were required by (usually old, like NYC) city codes

Here's an idea of what the fittings look like:
Adapters - Copper Fittings

Good luck!
~aaron

Quote:

Originally Posted by perduehouse

Our kitchen sink is on an island and behind the sink was a small countertop (bar) about 8" higher than the sink. We have new countertops that we'd like to install but want everything at the same countertop level (no bar) which means we either need a new air vent below the sink, or a very beautiful pipe that sticks out the top of our counters and extends to the wall! Can we:
A) lower the pipe to be the same level as the sink?
B) seriously, replace just that part of the pvc with a nice metal pipe that really does extend across the countertop to the wall (our kitchen is stainless/industrial style so it would be okay).

Help! and Thanks! :confused:

In Canada, we do it differently. The trap & vent are below the floor. The trap is connected and vented into ~horizontal pipe that runs to the drain in one direction, and up to a roof vent in the other. i.e. if you look under the sink you just see a straight pipe running from the basin down through the floor. Typically there is a cleanout visible on the floor of the cabinet, or the pipe has a mechanical coupling so you can remove everything in the cabinet to snake things out.

It's a bit more difficult to retrieve your wedding band after it slips off your hand and goes done the sink!

Quote:

Originally Posted by perduehouse

Can we:

A) lower the pipe to be the same level as the sink?

You can, but make sure you use drainage fittings (long sweep 90's) if you are horizontal and less than 6" above the flood rim of the sink.

Quote:

B) seriously, replace just that part of the pvc with a nice metal pipe that really does extend across the countertop to the wall (our kitchen is stainless/industrial style so it would be okay).

That would be cool, but is really unnecessary.

You could also just install an approved Air Admittance Valve under the sink at least six inches above the wier of the trap and eliminate the old vent by cutting out the exposed portion and then cap off the vent in the wall with a schedule 40 glue cap that is made of the same material as the piping (ABS or PVC).