26 replies to this topic

[FLASHINGROOSTER]

I see what your talking about in this diagram. It looks like most of the stuff in the house is hooked up to what I think is the secondary vent line. The only vents I cant find on drain lines are the kitchen sink drain line, and the tub, it has that over flow piping but no vent beyond that. All of this is exposed under the main floor in the basement so its easy to see.

 

The only thing I can't physically see is where the secondary vent line goes into the main floor. I can see it connected to the drain lines for the shower, toilet, sink in the basement, then it T-s up into the unknown. A wall in the main floor bathroom. Where it connects to the main vent stack is the mystery or if at all. Part of me is wondering if they shoved that pvc line up into the roof space.

 

You can see the main vent line in the basement and all the connections are from drains coming from upstairs. I can only see so far up the narrow channel into the first floor and into the roof space and eventually the roof vent cap. It might be connected farther up in the wall somewhere. 

 

But yeah there is no vent line on my washer setup your right. I am half wondering if I should cut a line into it, and change the Y to a T. It seems simple enough to do with the drop ceiling. Really easy actually

 

 

The T connection in that diagram for the laundry and wash basin is exactly what you are talking about. For discussion sake it serves the same visual as my washer and sump pump setup into the basement drain.

 

Now is that the only floor drain in my basement well that I am unsure. The only one I can physically see anyway other than the sump hole. There could be another one hiding under that flooring somewhere perhaps, but that is not important in regards to venting so much as flooding.

 

 

 

 Edit: Added this picture for educational purposes

 

 

 

 

Edited by FLASHINGROOSTER, 09 August 2021 - 03:07 PM.

[drmcnasty]

It should go through your roof and have a cover over it

[Juthro]

They also make air admittance valves (AAV's) that will do the same job.  They are a one way valve that doesn't need to be tied into a vertical vent through the roof.  They let air in when there is a vacuum on the line and then close to keep sewer gasses from escaping.

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Edited by Juthro, 09 August 2021 - 04:44 PM.

[TVCasualty]

They also make air admittance valves (AAV's) that will do the same job.  They are a one way valve that doesn't need to be tied into a vertical vent through the roof.  They let air in when there is a vacuum on the line and then close to keep sewer gasses from escaping.

 

Those things seem to work okay, but they make me nervous. I guess I don't trust the seal on the valve to keep sewage from pouring in if there's a back-up.

[Juthro]

I agree that hooking into an open air vent through the roof is a more reliable choice, but an AAV failing won't directly cause a backup of any kind.  They can get stuck in either the open, or closed position.  Open, and you are going to get some whiffs of sewer gas from time to time, closed and your line is going to drain slow, and possible glug air through the drain.

 

They do make an easy, and relatively cheap fix for systems that would require major work, and/or materials to tie into a roof vent, and I would much rather have an AAV on a drain, then no vent at all.

 

Another problem that not having a vent can cause is that the vacuum of the water going through the drain line can suck enough water out of the P trap that it will allow sewer gas back through the drain.

 

 

 

[TVCasualty]

I got stories.

 

 

Well not quite, but it was almost like that when a huge thunderstorm dropped in shortly after I moved in to my new place and the pressure dropped low enough to draw in gas from the septic tank through my shower drain ...while I was taking a shower. That was when I found out the shower had no P-trap. That was not pleasant.

 

 

[FLASHINGROOSTER]

Yeah if not out that vent backup will come out your toilet or your shower drain if you have them in the basement. I am not sure there is anyway to avoid sewer backup entirely.  It might buy a guy some more time but the lowest drain point in your system is where it will come out regardless

 

Not a great scenario when nobody is checking the basement room with the drains in it, and you keep flushing and or using the sink and shower upstairs without a clue, good times.....

 

So I busted out the ladder and grabbed my flashlight and took a look up in the roof crawl space. Like I suspected they ran the smaller vent line up into that space rather than twin vents up through the roof. There was no connection points that far up only solid steel pipe so the only option would be to cut another hole which seems unnecessary to me. You can see large grated vents open to outside air so it is certainly not an air tight space by any means. That one way vent might be the easiest solution but connecting to the secondary, lets call it the 1 1/2" vent system that goes into the roof space is very do able. Don't even need to drill holes due to drop ceiling. Just fab up and fit something like 10 ft of pvc pipe. Attach to wooden beams with one hole straps. Three or four nineties and a T and it should be fine.

 

 To err on the side of caution it would be the thing to do but then I have the custom holes to deal with as well. Not looking to try to remove that bushing I am a little concerned it would be a gong show. I suppose I could try to silicone those custom holes after piping in the vent line but not sure if It is going to make much difference at this point. It drains fine, I cant smell anything when I go down to water my plants daily, and to boot it has been like this for ten years or so.  I can't recall sewer smell other than the time my main sewer line got plugged up enough to cause a backup.

 

Mostly the smell of fresh cat pee wins the battle of odors in the basement

Edited by FLASHINGROOSTER, 10 August 2021 - 05:00 PM.