New Bathroom Sink - Tap Into Toilet Vent?

[Peteman]

Hello Everyone - I have a bathroom in my basement but it is just a toilet. I'd like to add a sink but am not too excited about bashing up concrete to tie into main drain line. I had the city inspector over for a new hot water heater inspection and asked him about tapping into the existing toilet vent. He says OK to bring the sink drain into it as long as the grade is 1/4"/foot (wet vent). The sink vent would tie into the existing venting in the ceiling.

My question is, how hard is it to cut into an old 2" cast iron cleanout tee and put in the new drain tee (need to get in around the level of that cleanout to make the proper grade - see red line in photo)? I assume a good sawzall (torch?) blade is needed. Another option would be to just cut totally below the cleanout in the angled part of the vent. Below are a couple pics showing the situation. Sink will go where the toilet paper roll is (another storage area is behind there where I can bring the drain over). Thanks!

 

[Sylvan]

When faced with this kind of set up Call a local plumber ask them to sell you a 2" piece of galvanized pipe


You take a measurement and see how long it is needed

Thread one side normally and the other side they need t make crooked thread and they will need a Rigid 65 R and adjust the rear guide slightly off center and this can give you 1/8 -1/4 " pitch

I did it many times on steam condensate lines to get some pitch on long runs and once in a while on waste lines

 

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[Reach4]

Did he say you could not enter at the cleanout where the plug screws in?

 

[Peteman]

Did he say you could not enter at the cleanout where the plug screws in?

Hi - the cleanout plug location is too high to get proper grade from the sink drain to the stack. I need to come in about 3" to 4" below that. I am interested if anyone has used a sawzall (with a good blade) to cut an existing cast iron cleanout tee about where I've marked it. Thought about trying to chisel out the lead and oakum but from what I've read, that's near impossible.

 

[Reach4]

What you need to do is to support the stuff above strongly before cutting. It would be two cuts. One or more riser clamps can help. You would cut at your red mark, and you would cut higher.

Thought about trying to chisel out the lead and oakum but from what I've read, that's near impossible.

I haven't read what you read. From what I read, you start with a drill, and drill down to the oakum in at least one section. Many holes near each other. You then pry. I would think a long bit would help, so the drill bit could be more vertical. I have never tried it, however.

 

[Jeff H Young]

You can even cut below the 45 whatever works and convienient replace with bands and plastic fittings put 2 x2 x1 1/2 santee at desired height replace clean out tee with either new one or clean it up and re -use at a higher location. Take care as someone else said to support pipe befor cutting . also cut out more than needed as your new plastic can have longer pieces in there as needed

 

[Jeff H Young]

Hi - the cleanout plug location is too high to get proper grade from the sink drain to the stack. I need to come in about 3" to 4" below that. I am interested if anyone has used a sawzall (with a good blade) to cut an existing cast iron cleanout tee about where I've marked it. Thought about trying to chisel out the lead and oakum but from what I've read, that's near impossible.

Didnt comment on this it might take several blades or they have a blade for this that Ive never used.
More importantly how are you going to remove that COT without cutting metal? gouging out the lead and oakum then what? it likely wont move Dont see a point in that. Go with saws all my advice.

 

[Reach4]

Didnt comment on this it might take several blades or they have a blade for this that Ive never used.
More importantly how are you going to remove that COT without cutting metal? gouging out the lead and oakum then what? it likely wont move Dont see a point in that. Go with saws all my advice.

Good point. Cutting would be needed anyway, but removing the pipe from the hub could make a nicer looking install.

https://www.homedepot.com/tool-truck-rental/Ratchet-Soil-Pipe-Cutter-6/69982/index.html

 

[Jeff H Young]

Sylvan had good suggestion But you said cleanout is too high? actualy I didnt look at first picture I thought vent was on otherside of block. You could put no hub and paint it . For that room in my house Id get crafty and make it work. I mean the lav is going in that room ? or like 20 feet away?
Im looking at the grout lines and the toilet and cant see why the COT is too high. Id go right in the T , not legal obviously . Just depens what you want its easy either way Id be done with it by now

 

[Sylvan]

If you going to cut the CI I would suggest use a grinder and wear protection a lot cheaper and faster then sawzall blades . When your near the end of a cut and cannot use the grinder any more then use the Sawzall


Removing the lead is NOT impossible we do it all the time. They make chisels strictly for removing lead it is shaped in a 45 degree angle or you can drill the lead in several spots use an old screw driver and pry it out

Using a large drill bit will make it a lot easier

We also burn it out wearing gloves and make sure you have plenty of ventilation as the lead becomes molten using a flat screw driver you can scoop it out . This is a messy method but it works

 

[Peteman]

Thanks for all the great insights. The sink will go on the wall to the left - the small sink I plan to order for this shows the waste C/L 23" off floor. Getting from there to the vent pipe (7.5 ft) I will need to drop about 2" for slope plus 6.25" (from drain c/l down through it's san tee and 90 deg sweep -see pic below). That puts me at 23" - 2" - 6.25" = 14.75". The COT is 16" off the floor - too high.

As of today, I think I may try to drill out the lead and scrape out oakum (after cutting the pipe about 1' above COT) and see if I can get that COT out cleanly, then use a donut fitting into that hub to put new drain into. If that doesn't work, I'll do as Jeff suggested and cut the 45 below the hub and work from there.

I'm planning on getting a permit for this so I hope I can get the city to go along with taking this drain into the vent. The idea of bashing up concrete and trying cut out CI below scares me. I see that as inviting disaster (and much more work).

 

[Jeff H Young]

Didnt know you were going that far with it ( not that it matters much) or pulling a permit. You are on track shouldnt be too bad a job