Remodeling bathroom- where’s the vent pipe?
I am remodeling my bathroom (house built in 1994). I’ve removed all the drywall and noticed that there are no vent pipes extending above the shower, toilet, or sink drain pipes and nowhere in the bathroom walls is there a PVC pipe extending up to the second floor and roof.
That said, we’ve lived in the house for eight years and we’ve experienced no drainage problems and no odors. So I’m assuming that somewhere in the system a vent must exist- but where? I am replacing our single sink with a double, our regular toilet with a wall-hung european style unit, and our tub with a walk in shower. Because no vent pipes are present, I was just planning to reroute the existing supply and drain pipes as needed to accommodate the new sinks, toilet, and shower- ignoring the venting issue because we’ve not had any problems to date.
Assuming a vent exists somewhere in the system, can someone please explain where it might be? Is it likely that the drain pipes underneath the bathroom- in our crawl space- route to a vent? Was this standard practice back in the early 1990’s? Could the tub and sink drains somehow be venting each other?
– Lyptus
Replies
Do you live in an area with strong code enforcement? Do you know if the builder was reputable?
There are some circumstances where the vents may not be obvious but still be there. Showers, eg, obviously can't have the vent rising right up from the trap in the middle of the shower floor, but code requires that there be a vent rising up from the drain line within a few feet of the shower. In other exceptional cases the inspector may permit a similar setup for other drain types. But the vent is supposed to be there, per code.
Sometimes you look for the vent above and can't find it, for several reasons. First off, it's common to connect together several vents rising up into the attic area into one common vent to go through the roof. This reduces roof penetrations which is good from a leak and appearance standpoint.
There's also what's called a "Studor vent" -- essentially a one-way valve that can be used (in certain cases) in leu of a vent that rises up through the roof. And with regular vents the vent pipe, after exiting the vented fixture in the usual fashion, can be routed downward (with some appropriate precautions) under the floor to a more convenient place for it to continue its upward path.
But it's also not unheard of for vents to be missing in areas where code enforcement is weak (or corrupt). Sometimes nothing bad happens, other times there is trouble with gurgling pipes, odors, and the rare but not impossible poisoning from sewer gas.
vent line question....
Howdy!
What floor is the bathroom on? Basement or above grade?
Please do not ignore the venting issue...it may cause problems in the future
that will be costly to repair. Better to do it right and while you can.
See if you have a vent stack coming out of your roof. Then, if you have attic acces, follow the pipe's path.
If you can see it, that's a great start. Try to follow that pipe's routing to your main drain. Okay. Now,
at least you've got an idea of how your house plumbing is vented (always good.)
Now, check your current bathroom plumbing....make a diagram of all visible drain lines, etc..
It is possible that this bathroom is somehow dry vented to a stack not in line with your current plumbing.
Please let me know what you can find, but I strongly recommend venting your bathroom remodel.
Hope that this helped!
Eric
no vents
I too seem to have the same problem, original house was built probably 1950's and both original baths have vents, but upstairs bathroom, addition probably added in the 70's I can see no sign of venting.
The drain pipes go straight down with no traps, embedded in concrete, and no sign of vent pipe on the roof. I have the interior walls exposed and no sign there of vent pipes there either.
so to redo it right do I have to jackhammer the the concrete around drain lines and add vent pipes? or is there a chance they actually had a proper method I don't know about. thanks, marcia
I don't understand -- you have a concrete floor upstairs? Or, as you say, do the pipes really go STRAIGHT down, with no bends? (If the latter then that bath is a MAJOR violation!!)
For a sink the vent rises up from a tee in the wall as in the picture. A toilet is similar, only the toilet itself creates the U-shaped "trap" so it's a straight pipe back from the toilet to the wall and the tee, so the vent pipe generally rises up from the floor.