Hello,

I have an old house (100-years) and have a couple of questions about venting. Here's the details of each floor:

Basement - washer & utility sink, / shower, sink, & toilet
1st Floor - kitchen sink, garbage disposal, & dishwasher / sink & toilet
2nd Floor - tub, sink, & toilet

My main stack is 4-inch cast iron and appears to be in good/very good condition. Currently, I have a 1 1/2-inch PVC vent (I believe this to be a stacked vent) that runs from the basement to the second floor, where it becomes 2-inch cast iron, then runs to the attic where it ties into the main 4-inch stack that vents through the roof. I'm uncertain if it makes any difference, but each toilet on each floor is located within a few feet (approximately 3-6-feet) of the main stack. And, the 2nd floor bathroom sink vent ties into the system in the attic vs. on the second floor.

I currently have access to the vent pipe/stack on all three levels. My questions are:

#1 - Should I have a 2-inch vent vs. the current 1 1/2-inch?

#2 - Should I vent my basement bathroom group through an un-used 1 1/2-inch cast iron vent that exits the house on the basement stair landing, runs vertical along the brick exterior and vents above the roof/gutter?

#3 - Can I plumb my 1st floor bathroom sink drain into the current vent? In other words (if I have the language correct), can I wet vent my basement washer and utility sink?


Thanks,

-Chad

1 - Should I have a 2-inch vent vs. the current 1 1/2-inch?
Although 1 /2" vents are acceptable in some areas we vent all out new homes with a 3" main vent and 2" for the others.

#2 - Should I vent my basement bathroom group through an un-used 1 1/2-inch cast iron vent that exits the house on the basement stair landing, runs vertical along the brick exterior and vents above the roof/gutter?

If it's already there I can see no reason not to use it.

#3 - Can I plumb my 1st floor bathroom sink drain into the current vent? In other words (if I have the language correct), can I wet vent my basement washer and utility sink?

What current vent? You have a full bathroom group that you're attempting to wet vent? You haven't given me enough details to give you a answer. Regards, Tom

Tom,

Thanks for your response. I posted a similar question today. I doubt if I could fit in a 3-inch main vent without doing major demolition and repair work. I'm trying to improve my DWV system, and in doing so would like to meet today's standards if possible.

#1 - Is a 2-inch main vent adequate for:

Washer / utility sink - basement
Kitchen sink with garbage disposal and dishwasher - 1st floor
Bathroom sink - 1st floor (toilet connects directly to main 4-inch cast iron stack)
Bathroom group (tub, toilet, sink) - 2nd floor

The tub and toilet on the second floor connect to this vent on the second floor and the sink on the second floor makes it's connection in the attic, where the vent system connects into the 4-inch cast iron that exits through the roof. Is this vent system called a stacked vent? And, is this venting method acceptable? What else would you recommend?

#2 - I'll plan on using this un-used 1.5-inch galvanized vent for my basement bathroom group (sink, shower, toilet).

#3 - I apologize for the poorly written question. I'll plan on connecting my 1st floor bathroom sink drain to the 2-inch kitchen sink drain located in the basement. This method will prevent any wet venting.

Thanks again,

-Chad