Please see this picture. The trap in the background is for the upstairs tub which has no vent. The galvanized elbow you see is the vent for the downstairs tub that I am going to replace with PVC. Is it worth trying to "t" in a line to the upstair tub to vent it. The pipe there is 1 1/2 inch and on the other side of the joist it couples to 2 inches for the rest of its non-vented journey to the basement main line out which is 4 inch PVC. I was thinking of tieing in a "t" on the immediate opposite side of the joist (because the ceiling is exposed there and it is with in 2 feet of the drain) and running 2 inch pvc to the vent and t'ing it in to that vent. Is this legal, recommend, or a smart thing to do? The ceiling is open so if I do it I do it now. Also it might help the upstairs vanity drain which also has no vent and is about 4 feet away. Now I think I know that the vent needs to connect above the flood line, i.e. much higher than what I am able to do. SO that is the question as to whether I should do it at all.

Thanks for posting photos of your project. It sure makes thing lot easier to evaluate and than to advise...

Fernco looks like the coupling you posted. ( rubber coupling with metal shield and 2 clamps ). Since both pipes have slightly different O.D. they make them so one side fits Galvanized Pipe and the other side fits PVC pipe. Usually, Home Depot doesn't carry those. You would have to go to more professional store, like Ferguson Enterprises or Hirsh Pipe and Supply. See the Fernco catalog at: Fernco Couplings, Flexible Couplings, Flexible Pipe Connectors, Fernco Fitting, Shielded Couplings, Fernco Donut, Pro-Flex Coupling, Large Diameter Couplings, Sewer, Drain, Waste, Plumbing Flexible Couplings, Plumbing Pipe Leak Repair | Fernco

Yes, definitely, it is always worthy to add vent to a tub. With vent present, tub will make less ( or none ) gurgling noise while draining. Since you have open walls, it should not be such a big deal. Just make sure you connect upstairs tub vent at about 48" above finished floor.

Thanks, but that is the problem. I can not connect the upstairs tub above the upstairs finished floor. Only at the level that is pictured. I am peeking up through the ceiling I removed looking at the bottom of the finished upstairs bathroom. I only have access to the pipes from the angle you see in this picture. Upstairs the bathroom remains finished and also the roof line gets in the way. So I was wondering if it was worth it to connect it at the level pictured by just coming across the empty gap you see with 2 inch pvc into the current vent which continues up through the roof after making some zigs and zags. Would this be a damaging thing to do as less than perfect option. Should I do it or leave it alone. I don't want to ruin the vent for the tub below by making this connection if it has no benefit. Your opinion would be very helpful as I am about to start redoing all the other pipes.

Milos code likes to vent everything that has a trap. You would have to roll a fitting up on a 45 to take off for the vent and I can see a space problem doing that. Older homes have been venting their tubs through the tub waste for decades with no problems except a gurgle when draining. I can see a lot of hassle with no real advantage to adding a vent on the tub. I'd leave it as it is. Good luck, tom

Well, if that's the case than we have a problem. You could install AAV vent and bring it up behind the tub in the cavity between the tub and wall . This would not require wall cutting. All could be done through access panel.

Since water level in tub is higher than the potential vent connection ( below the floor ) that water from the draining tub would enter vent and tried to drain through there.

PS: Don't really like that sharp, horizontal 90, directly behind the trap. That certainly slows drainage.

Thanks for your advice. I took one more pict so you could really see what I am talking about. Looking at the picture that is a wider shot: The PVC in the back that reduce from 2 inches to 1 1/5 inches and goes through the joist is the tub drain from the other picture (see picture on the right or bottom). The p-trap from the picture on the right is on the other side of that joist. The galvanized metal pipe on the right is the vent from the tub below that I was suggesting that I tie into. The left side of the picture has the galvanized pipe that is the drain for the upstairs tub and the vanity which you can see to the far left. I was wrong about it being a double trap (as I stated in an earlier post). As you can see neither are vented and just tee into the galvanized drain which ties in to the 4 inch main line in the basement. I am going to put the AAV in the vanity as discussed and I am going to redo the pipes you see and replace all the galvanized pipe with 2 inch PVC. My though was to bring a vent over from directly between the upstairs vanity and tub into the vent all the way on the right. It would be easier working in the area in this pict as the ceiling is gone. The p-trap for the upstairs bath is in the area where the closet is. Anyway, I wanted you to see this pict in case it changed you mind about whether there is a benefit to tieing in a vent at this level even though it is below where it really should be. Let me know your last word. Thanks!

Everyone away for memorial day? Have a good weekend.

Jjastinia: thank you for asking. We are staying in town for Memorial Day...

Also, I am noticing your copper pipes are cemented in the concrete-block wall. They should be loose and penetrating wall through larger hole, than sealed with approved sealer that expands.

60psi is a bit higher than 45-55psi recommended. But I don't think the 5 extra psi makes such a difference.

Hi, thanks. I am not seeing where the pipes are cemented. Which picture are uyou looking at?

I can turn down the pressure on the PRV. What was your opinion about the venting issue now that you see the larger perspective?


If you are looking at the earlier set of pics from the basement the 3/4 pipes that are going through the wall are heating pipes and those particular pipes are capped dirctly on the other side. It is a zone that is not in use. Although I just realized that circnpump does turn on but the water goes no where ss the pipes are caped 10 feet away.

Help! I screwed up. I was on my last pvc schedule 40 joint, it was a 2X2x2 wye and I accidentally primed the wrong hub which I was not ready to glue. I only put purple primer on and no glue. I was upside down. Anyway I needed my upstairs shower working so I glued up the correct line to the other hub. But now I am left with the one hub on that wye primed (no glue!) and dried. I will not be doing that line for two more days. My urgent question is can I still use that hub or do I have to cut out the wye which would screw all the measurments up. Is it possible to scrape off the primer and then just reapply and glue. Your help is needed!

Thank you!

You do not have to remove the primer. The reason we paint the fittings with primer is to remove the glaze on the two pieces to be cemented/welded together.
You can do the same thing with sandpaper. Your fitting will be just fine. Good luck, Tom

Thank you! So I should just leave the primer there and I assume just reaply fresh purple primer over the old primer when I am ready to actually glue? That is great. I really thought I was going to have a big problem.

OK. Now when I tried to link two fittings, the length of 2 inch pipe I cut was a little to small I think. I feel like the ends only went in 3/4 or a little less of the way into the hub. And then I had to push the entire length over about a 5 degree to get it to line up. Do you think that will hold up? The joints seem tight but I am not sure if this will leak in the future. What are your thoughts? I have enclosed a picture and circled the joints I question. They may be fine I really can't tell. Also I have enclosed a picture of the trap in the other side that that length connects to (I have not glued it up yet, but there is not much room to change it). What are your thought about this. The trap goes right into a sanitary tee and then drops into a 90 which slants down to the main out. The vent is coming out of the top of that sanitary tee. I am wondering if I have inadvertently created a s-trap due to the space limitations? Let me know if this is OK?

PS I know I did a sloppy job with the primer. What can I say. It runs everywhere and I have no idea how to control it. I am purple.

Here is another angle of the trap. I hope it OK because there is no room for anything else.