No you can not.
Might seem like a silly question, but please bear with me.
I know that venting must go vertically up 6 inches above the highest fixture, which is usually the sink prior to going horizontally.
My question is, once I go vertical, let's say 20inches above the rim of the vanity, can I go horizontal for a foot or so, then go downwards vertically for 30 inches, and connect to a vent?
No you can not.
Broken promises don't upset me. I just think, why did they believe me? -Jack Handy
It will trap condensation and over time will seal off the vent.
It will work because condensation will drain both ways, but I doubt that you would ever find an inspector who would approve it. They usually only know what is "in the book" and cannot visualize how anything else would work properly.
Here is my situation. The bathroom is in a dormer in the attic that has one wall that is an outside wall but there is a 2 feet crawl space on the bottom. So I was thinking of wenting from the sink go up then down then around to connect to the 2 inch meta venting that goes to the roof.
What would you do?
Last edited by keano016; 03-12-2011 at 05:29 AM.
I cannot make sense of the drains in your drawing, but it appears that the lav can be vented into the 3" CI or go straight up through the roof.
Yes, the cast iron is there, but I am nor sure how I can tap into the cast iron, especially since there are two cast iron pipes connected there, one 3 inch that is the drain from the toilet plus a 2 inch that is a vent from the lower floors.
I want to avoid going through the roof because of the fear that I may not do it properly and then there is a leak or I fall
if I can go around the small wall, which requires going below the highest fixture, then I can connect to the 2 inch metal venting on the oposite wall.
The "proposed vent" on your drawing doesn't make any sense at all...
You're going to have a tough time tying into the 3" CI stack at the proper height, so your best bet is to go through the roof... It's not a big deal...
I agree. That's why I was asking, altough I kinda expected you guys will say no to going down below the fixture. I still do not see the problem thou.
This (I think) would be the correct way of sharing a vent (the red line). So why is it you can't do it that way? It might need to be higher than I placed it but that's the general idea.
Last edited by keano016; 03-13-2011 at 10:34 PM.
Does it have a tee currently where I am showing the red line tapping into it? If so, could you not remove the tee and plus a 4-way ( + ) one? And anyway, your proposed vent had it going over there anyway to that exact spot. I just cut out the extra wasted amount going up, across and back down.
sorry about the confusion in the drawing. A 2 inch cast iron ties with a 45 degree tee into the 3 inch cast iron. The propose venting was passing trough that area but it was not connected. I was planing of going pass the 3 inch cast iron then turn 90 degrees to go behind the low wall and conect on the oposite side where the 2 inch venting is. That's why I was asking about going below the highest fixture.