View Full Version : waste, vent questions please ...
04-02-2005, 09:57 AM
I'm laying out a 2nd floor bathroom.
All shown runs are horizontal (except for slope in the waste pipes - and the vent pipe, which eventually rises to meet the main stack)
1. Can the sink waste run join the shower waste run as shown?
2. If so, can the shower and sink vent be the same as shown in this situation?
3. Can the vent pipes be Tee'd off where the waste pipes go down to the basement or do the vent pipes have to come off closer to the drains or closet flange?
Thank you very much for any input.
Note from Terry: Plumbers have to work with a journyman plumber for 8,000 hours before they can take the commercial written test.
Forgive us if we seem impatient with some of our answers.
We don't want anyone to ruin the home for the next owner.
They are all incorrect. The sink vent has to come off the drain pipe where it comes out of the wall behind the sink. The shower drain may be able to connect to that drain pipe and use its vent. The toilet vent has to be within your maximum distance from the ven to the actual opening in the floor. That distance can be 5', 6', or 10' depending on your code.
04-02-2005, 11:11 AM
Thanks hj - I appreciate your input.
the wall behind the sink doesn't provide space or routing for a vent (or drain. I am actually planing to drain through the floor ((pedestal sink)).That's why I was hoping that I could vent it as shown, further down the drain pipe.
Can the shower and sink share a drain pipe?
The toilet vent has to be within your maximum distance from the ven to the actual opening in the floor .. .this I didn't even understand, could you please explain?
04-02-2005, 11:57 AM
If you can't fit the waste and vent in the wall behind the lav, then you can't put the lav there.
You can't drain the lav from the floor. The trap arm needs to be horizontal with a slight 2% grade down.
Lav, maximum trap arm distance for 1.5" pipe is 42"
Shower, maximum trap arm distance for 2" pipe is 60"
All waste fittings below 42" should be sweeps and wye fittings unless they are tees placed vertically.
In most cases, you would have a vent for the lav, and a vent for the shower, these vents could tie together at 42" from the floor, or they could go up through the roof separately.
If you look at the houses in your neigborhood, you will see many pipes sticking through the roof.
These are vents.
There is a reason for them, it's not new science.
The toilet must also be vented within certain limits.
Measuring from the floor to the vent, along the centerline of the pipe, in most cases the maximum allowed distance is six feet.
04-03-2005, 06:17 AM
Thanks for the all the great info ...
I know I could put ten vents on my roof, but I don't want to. They are ugly. Maybe not to you but certainly to my wife. If possible I want to combine them all into the one existing main stack which is in the back of the roof.
I'm curious though what they do for vents on, lets say an island sink, with no walls in sight? There must be a (legal) way of draining and venting without walls, no?
Thanks again ...
There are at least four "legal" ways to do it, but usually only one or two are "legal" in any given jurisdiction. Each municipality has its own "favorite" way of doing it.
04-03-2005, 02:19 PM
"I'm curious though what they do for vents on, lets say an island sink, with no walls in sight? There must be a (legal) way of draining and venting without walls, no?"
Most legal ways of having an island sink still has a vent that winds up going through the roof.
Are you thinking that plumbers hadn't thought of that yet?
It's all spelled out in the code book.
It's not obvious from the top that there is a vent, but below floor level, the vent is taken off useing waste fittings and run up another wall.
Your wife may think that vents are ugly, but they do serve a big purpose.
If you're going to plumb the house based on. "I don't like how that looks" then be prepared for problems later.
One realtor I know always hires a "handyman" to do his plumbing.
He shows me the work when he wants to know why things don't drain.
Guess what I get to see. No vents anywhere. The handyman didn't think they were needed. So now when he drains his nice jetted tub, it backs up into the shower right next to it, black gloppy goo. It leaves a nice residue too.
Then when he drains his kitchen sink, it overflows the washer drain downstairs all over the floor.
I'm sure the handyman saved a few bucks on fittings and pipe, the homeowner is then stuck for the life of the house with crap.
On combining vents, at 42" above the floor you can combine the vents. If you are going over the max for horizontal distance, you can go up a pipe size.
You have to maintain the "area" of the pipe leaving the house.
If you have a 3" going out, you will need at least one 3" vent or a combination of pipes adding up to that, something like two 2" vents and one 1.5" vent.
Plumbers have to work with a journyman plumber for 8,000 hours before they can take the commercial written test.
I'm sure your job isn't learned in a day either.
04-04-2005, 05:41 AM
thank you ....