View Full Version : Old tub with no vent, and it drains! Why?!
jpb116
02-19-2008, 07:44 PM
So I have a tub/shower on the main floor of a ranch. It's 40 years old and during a remodel I've opened the ceiling below it (finished basement) The tub doesn't have a vent. Just the standard drain, trap etc. It's about 8 to 10 feet from the main drain out of the house. So how does this thing drain okay? Is it venting through the overflow? And lastly, can I plumb the new tub the same way? :confused:
It has to have a vent (unless a previous owner made his own plumbing codes). Is there a branch within 5' of the bath trap? A lav/basin drain?
The vent is there to keep water in the p-trap from being siphoned out.
Its not being vented from the overflow.
And lastly, can I plumb the new tub the same way?Not by any code that I am familiar with. You need to have a dry vent or a wet vent with in 5' of the fixture trap
jpb116
02-19-2008, 08:08 PM
The nearest vent is upstream and about 7 feet away...
The nearest vent is upstream and about 7 feet away...
can you tell if its a dry vent or a wet vent?
Which ever one it is, we may be able to make it work for your application with a little bit of altering.
A pic of the area would be helpful to see what room you have to work with
jpb116
02-19-2008, 08:35 PM
All this being said, My intent is to demo the area... I'm going to vent to code in the rebuild. I was just curious how it would actually drain in this configuration ... mabe lucky?
Here are 2 typical examples of dry venting and wet venting. If you decide to go with either one, we can help you with the sizing of piping
In most cases a vent has little to do WITH draining, it comes into play AFTER draining has finished so that the process does not compromise the trap's seal. As a practical matter, most drains would work much better without a vent, because siphonic action would be more effective than hydraulic pressure.