Existing dry vent - 2nd vent in house

I almost hate when I learn something new, my house is from the 50's
I read 2 threads here today about washing the bottom of the vent stack
One side has the main stack, 2 full bathrooms, & 3rd shower/sink/dressing room; town sewer exits the house
The vent goes up thru the roof - 3" vent

A 3" drain leads to the other side of the house
Tied into this is the washing machine (basement)
The drain then drops to 2" & rounds a corner
The kitchen double sink then ties into the drain (wet vent)
The drain then goes 3' past the sink - turns towards the outside wall - then proceeds up thru the wall & out the roof - 2" vent

So it appears that I have a dry vent on this end of the house
The sink has an "S" trap - this will be eliminated when the kitchen is renovated

I'm considering moving the 2" vent to the other side of the sink

Since this is all pre-existing I know I can leave it
But since building the garage/addition on the kitchen side it seems like a good time to make this right

Dave,
If you have no issues I wouldn't worry about it. Right is right for the current code, I'm sure your house was built to it's current code. If you start updating everything, where does it stop?

vent

I am not sure what you think your problem is, because I do not see any if I am reading your posting properly. EVERY building has one, or more, "dry vents" which is the portion above the highest drain connection.

In another thread here it stated that the bottom of the vent stack needs to be washed by a fixture. Mine is not
If that's not a big problem then I will leave it
I guess its existed for 50+ years

The kitchen sink used to have windows behind it
Now its a wall, so I also wanted (required) for the new sink to be properly vented. That would mean going up & tying into the cast stack somehow
A dishwasher will be going in - but that will go thru the sink?

That was also why I was thinking of redoing the stack

A plumber will be doing this work
I just want to know what I should have done
I'd rather have it all done at once

Scuba_Dave said:

In another thread here it stated that the bottom of the vent stack needs to be washed by a fixture. Mine is not
If that's not a big problem then I will leave it
I guess its existed for 50+ years

The kitchen sink used to have windows behind it
Now its a wall, so I also wanted (required) for the new sink to be properly vented. That would mean going up & tying into the cast stack somehow
A dishwasher will be going in - but that will go thru the sink?

That was also why I was thinking of redoing the stack

A plumber will be doing this work
I just want to know what I should have done
I'd rather have it all done at once

Click to expand...

The dishwasher will probably tie into the fixture drain of the sink above the trap.

Yes, I was thinking the dishwasher wasn't a problem

Here's the other thread about the bottom of the vent - needing to be washed by a fixture?

https://terrylove.com/forums/showthread.php?t=29650

vent

I know what you are referring to, I am just having a hard time following your description of the piping and seeing where the section you are referring to is.

This is a very rough outline of the plumbing
The green circle is the vent that is not washed by any fixture
If it is required by code I'd like to plan for it now rather then have it be an issue when the kitchen is renovated
Thanks

vent

According to your drawing it is immaterial, because that vent is not being used by anything as long as the kitchen actually has its own vent, which it should since that section of pipe would not work as the kitchen vent anyway.

Actually now that I think of it you are right
The laundry has a AAvalve, not sure I can upgrade that
Very little room to run pipes,its up against the floor joists (basement)
The kitchen sink does not have any vent right now & has an S trap
So possible this vent is keeping the sink trap from being syphoned out?

So I guess I'll have the plumber run a new vent & get rid of the old one. New vent & new kitchen sink, possible a bar sink will be tied in at some point. So might as well go to PVC. I think the kitchen renovation is sometime next year

Thanks !!

vent

That vent, at that location, cannot possibly vent your "S" trap, and it is siphoning out most of time, depending on how much water you drain from the sink. A running faucet probably does not do it, but draining a sink full of water would.

Well luckily the wife doesn't fill the sink much
It is a double sink. I don' think that makes much difference?
There used to be a double window behind the sink
So a vent was never installed
They could have gone to the right & tied into the main stack
I'm sure they didn't since it would have required cutting some 2x studs on an outside wall - maybe along 4-5'

I'm glad this came up before the kitchen renovation
One more thing for the list for the plumber

vent

WE go around the window all the time, usually in every house we do the plumbing in.

Yeah, I'm not sure why they did not go around
But the installation is original from when the house was built in the 50's. The sink & counter were original too, plus kitchen cabinets.
Sink is the same. Recd a free countertop that looke dmuch better so put that in 2 years ago

I think the thickness of the cast would have eliminate dteh 2x4's in that area - an outside wall. Only reason I can think that they skipped it