Re: Venting a new sink, is it needed, easiest option?
There are two ways of dealing with this. Probably the easiest, which may or may not be acceptable to the inspectors in your area, is the vent cap you mention. It allows air to enter the drain so the trap doesn't get sucked dry, but prevents sewer gases from entering the room. Some places may require that this vent cap be placed above the high-water level of the sink.
The other way, which is more complicated but accepted everywhere, is to emulate an island sink vent. Here is a thread on another forum that describes it.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.