I am the homeowner of an 1860 Victorian with a steep-pitched roof with four gables in an x-form. We have three toilets, one downstairs, two up, one of them above the downstairs. The vents are on the back of the end gables, about half-way along and fairly close to the eves. Each extends above the roof surface about a foot. There is also a barn attached at right angles to the back at one end, creating effectively another gable.
When the wind blows toward the back of the house, into the ell of barn and house (meteorologically rare), there is a strong smell of septic tank in the bathrooms. The downstairs bathroom used to be the main source, but we had the seal under the toilet replaced, and now it smells sweet. However, the upstairs bathrooms now smell terrible. The smell is also detectable in the attic. We are assured that the seals are in good shape (which I find hard to believe). When the wind is from other directions, everything is fine.
It has been suggested that the vents are not high enough, so that the gables create a high-pressure area that is forcing the gases back down the vents.
What do you think? If the vents should be raised, how high relative to the ridge?
Replies
I don't have an answer, but I'll ask a couple of questions that will get your post back to the top: Have you tried sticking your nose next to the tub/shower drain and the sink drain in each upstairs bathroom (functioning traps should eliminate these as possible sources of the smell, but........). The toilet bowls always have water in them, correct ? (No strange Venturi action sucking them dry...) Do these bathrooms have fans that vent to the attic or somewhere close to the plumbing vents ? (Maybe wind forcing the gases back through the ducting and into the bathroom ? So maybe stick your nose next to the exhaust fans also ?)
Maybe the smart guys will now see your post.
"R" is on the right track!
Standard building practice is to set the top of the sanitary sewer vent pipes at 5 to 12 inches above the roof plane. More will cause the vents to frost shut in the winter.
The vent is supposed to allow the down flow of water to "suck" air from the vent, thus allowing for good fasf flow. The stacks are sealed from the interior of the house by water filled traps at all fixtures.
In order to have "sewer gas" smells in the living space, either a trap is empty or not present, or the vent is breached into the houses interior.
I have a tub that is improperly plumbed (1972). The drop on the tub was at the end of a wet vent and adjacent to a structural beam which allowed no room for a typical waste & over flow plus a trap....so the "plumber"made a long drop and added the trap down line where ther was room. Then went (an apparent after thought )upstream of the trap and tee-d in a vent to the attic and out a roof vent.
On the days with windy conditions and if the stopper is not in the tub...it will stink!
If the whole house fan is on and not enough windows are open.....then it will back suck sewer smell if the tub stopper is not down.
.................Iron Helix
So take "R"'s advise....check out other alternative avenues....follow your nose!
I was think 'P" traps too.
Thanks a lot guys. A little research turned up a vent pipe rising from the washing machine to the attic (also in one bathroom) and stopping there in midair. The vent pipe through the roof starts in midair about six feet away and rises, not connected to anything. Strong small of septic tank between the rafters where the vent rises from the bathroom. Bathroom fan (venting to the attic) about four feet from the unconnected vent pipe.I will connect the two vent pipes and see if that cures the problem. I am hoping that the tub, basin and toilet are all connected to this same vent (there don't appear to be any others, but the connections, if any, are all hidden in the wall. There are certainly no other vents exiting through the roof.).
That bath fan venting into the attic is another problem.
Joe H