Move sink drain into exterior wall?

[Nicho247]

Hello All -

Homeowner/DIYer posting here.

I need guidance on if I can move this drain pipe for a kitchen sink and what my options are (in Tennessee). I'd like it go be hidden in the wall if possible.

It currently comes up through the floor as a 2" PVC pipe. My thought was in the crawlspace, reduce it from 2" to 1 1/2", come up with a 90 degree elbow (or some angle to navigate/clear the cinderblocks. Afterwards, come straight up through the wall/horizontal stud, through the outlet box, 90 degree elbow and then out into the kitchen. Is this possible? If not, what are your thoughts/alternatives? My main concern is (1) fulfilling code requirements with the hole in the stud, (2) is reducing to 1 1/2 " a big deal?, (3) is the outlet box a good idea/worth it (vs still coming up through wall w/o outlet).

View attachment 78830

 

[Breplum]

Always stick with 2". For getting over foundation, two 45s often work.
your attachment is not the right image

 

[Sponsor]

 

[WorthFlorida]

If you are worried about cutting the wall stud, stud shoes are made just for this problem. This site has most types made. https://www.fastenersplus.com/collections/stud-shoes

As breplum suggest, stay with 2" all the way. If you come up from the crawl space inside the cabinet, be careful that you do not create an S trap. You'll probably be more than 5 feet from the existing vent, an AAV can be used under the sink. Don't forget that 1/4" slope will be needed and a 2" PVC pipe needs to be supported every 4 feet horizontally. Tennessee is IPC code and Air Admittance Valves are allowed.

 

[Nicho247]

Always stick with 2". For getting over foundation, two 45s often work.
your attachment is not the right image

Hello Breplum - thank you for pointing out that the attachment is wrong. I don't know what that photo is. I didn't upload that nor own the photo. Strange. I have uploaded a new attachment and will check that it is what I am uploading.

What is your rationale/wisdom on why to stay with 2"? I don't disagree, just am unsure what is wrong with 1 1/2"? Is it that this may introduce slow drainage issues or something else?

If you are worried about cutting the wall stud, stud shoes are made just for this problem. This site has most types made. https://www.fastenersplus.com/collections/stud-shoes

As breplum suggest, stay with 2" all the way. If you come up from the crawl space inside the cabinet, be careful that you do not create an S trap. You'll probably be more than 5 feet from the existing vent, an AAV can be used under the sink. Don't forget that 1/4" slope will be needed and a 2" PVC pipe needs to be supported every 4 feet horizontally. Tennessee is IPC code and Air Admittance Valves are allowed.


View attachment 87656

Hello WorthFlorida - thank you for your guidance. Seems you concur with Breplum. Any further elaboration on the 2" vs 1 1/2"? Is this simplicity/standard in all homes?

Is a stud shoe necessary on a horizontal stud? All of the examples I have seen were on vertical studs. Never used one, but looks very simple & straight forward. Seems like a why not? Note, on the S trap, AAV, and slope. I am not planning on modifying the current slope and this is going up, so slope will be maintained/exceeded. After coming out of the wall, will do a standard P trap & AAV. An AAV was installed in the sink that I removed.

 

[WorthFlorida]

A horizontal beam (not stud) is a floor joist. The exterior wall studs sit on a "sill plate". It doesn't look like you can notch unto it since there is cement block.

A kitchen sink trap is 1.5", drain pipe can be 1.5 but there is no difference in cost and with a double bowl sink, or a single bowl 30" wide plus add a disposal, 2" is always preferred. You may need to add a clean out under the sink. It is usually above the trap drain.

As breplum also suggest, use two 45º to get above the the cement block. At the wall itself you will need a 90º elbow but be sure is it a "seep" elbow. If you are going with a granite or quartz, you can bump out the sink cabinet 2.5" to keep the pipe behind the cabinet. It can make the job look real good. If you are coming up inside the cabinet, place it near the corners to allow easier setup for the sink trap(s). It will also allow little or no interference for a pull down type faucet. They all use a weight on the hose and a center drain connection it is always in the way. There are dozens of configurations for kitchen sink traps especially with double bowl sinks. Search this topic to see what will fit best for your install.

https://terrylove.com/forums/index....backs-up-drains-very-slow.101091/#post-727441

 

[Nicho247]

Update here.

I did complete this section of my home renovation (sans baseboards), however I have hit a snag. I am seeking any guidance here for root cause/fixes for the simple DIYer that I am. What did I do wrong &/or what should I do to remedy the situation?

As previously noted in the above posts, I did end up going with two 45degree joints to navigate the foundation wall, use a seep 90degree elbow, 2" diameter pipes and an AAV. Unfortunately upon the final hookup with the sink drain, the drain does not drain much at all. It will drain, but extremely slow. I first believed that the AAV was not high enough, and after increasing the height, the problems seems to have gotten worse. I had enough foresight to get threaded fittings for that, so I am able to shorten it back down. The drain & p-trap is standard 1 1/2" and then couples to a 2" to 1 1/5" reducer, T joint, and then into the 90degree seep.

None of the other sinks/bathrooms have a problem with drainage. This is exclusive just to this extension of the drain into my kitchen area. As far as I know, the slope of 1/4" is maintained through this horizon drainage area up to where it connects with my mudroom/bathrooms.

Note - I did have some HVAC trunk and branches reworked such that they are now suspended from the floor joists (vs on the ground). Don't believe they altered the slope of the horizontal drain, but its possible.

I am thinking this may be a simple fix or worst case cut a hole in the floor and run the drain pipe straight down after the p-trap & aav.

Here are some pictures.

 

[Jeff H Young]

What was the box for? Yo might look cleaner to put the water lines higher

 

[Nicho247]

What was the box for? Yo might look cleaner to put the water lines higher

oh, just cosmetics. its one of those washing machine boxes. wanted to avoid a hole in the floor since the wife wanted the kitchen to be 'open' with little to no cabinets.

 

[Tuttles Revenge]

I don't see anything wrong with the installation that is viewable from these new photos.

If you removed the AAV would the sink drain quickly?

This same issue has come up at least 3 other times in discussion this past week or two. The consensus being that something is blocking the drain. Either a blockage or a belly in the pipe. The reason the drain is slow, is that as the water is travelling into a pipe that is blocked the air needs to be displaced. If it has nowhere to go quickly it filters through the clog/belly slowly. If you opened up the AAV then that displaced air would exit the vent.

 

[Nicho247]

I don't see anything wrong with the installation that is viewable from these new photos.

If you removed the AAV would the sink drain quickly?

This same issue has come up at least 3 other times in discussion this past week or two. The consensus being that something is blocking the drain. Either a blockage or a belly in the pipe. The reason the drain is slow, is that as the water is travelling into a pipe that is blocked the air needs to be displaced. If it has nowhere to go quickly it filters through the clog/belly slowly. If you opened up the AAV then that displaced air would exit the vent.

Hello Tuttles -

Yes & No.

With the AAV attached. if I run the sink, the sink will back up. I unscrew the AAV, and some water may spill out the top. You can hear the air sucking in/out and the sink drainage speeds up. Why would it back up with the AAV attached properly? This lead me to believe that the AAV was defective or the height was insufficient.

I then extended the height of the AAV (its extended in picture). In running the same test, when I unscrew the AAV, some water may spill out the top, however it no longer drains quickly. It just drains slowly. This is where I am now, thinking that I should shorten the AAV height back to original and there is some other thing going on.

From a troubleshooting perspective, if the AAV is working properly and there is an obstruction in the pipe, should i run a snake through it?

For background, the drainage pipe is clear up to the area that I installed/welded. I know this because I removed some of the pipe and did the install on the new section (see original pictures). There hasn't been an opportunity for something to clog the pipe up until now since I did not have the sink hooked up. This only leaves the P-trap as a culprit and it is empty. So, I am thinking its some other issue, but I am not the expert. Happy to run any sort of troubleshooting ideas to pin down the problem. Totally open to any ideas. Last resort would be to cut the pipe, and run the drain up through the floor. I will be very sad if I have to do that given I already laid the floor down, reworked subfloor, joists, and with the HVAC fixed, it is physically difficult to get to that section in the crawl space.

Nick

 

[Tuttles Revenge]

If anything is obstructing the drain is the most likely reason you see water coming out of the top of the tee.

 

[Reach4]

If the AAV is in place, fill the sink to maybe 2 inches with the drain plug open. Then how long does that take to empty the sink? The purpose of this is to see how complete the blockage is.

Rod/snake the line.

If you put a 2-way cleanout in the crawlspace, that could be useful for both diagnosis and snaking.

 

[Nicho247]

If the AAV is in place, fill the sink to maybe 2 inches with the drain plug open. Then how long does that take to empty the sink? The purpose of this is to see how complete the blockage is.

Rod/snake the line.

If you put a 2-way cleanout in the crawlspace, that could be useful for both diagnosis and snaking.

Ok, have the AAV in place (it is heighten as in prior pictures), filled sink about 2 inch, no stopper/plug. Would not move a millimeter after 20 min. After 20 minutes, I removed the AAV, no water came out the top, and does not appear to be draining after waiting 5 minutes. Also, water is at about the height of the AAV in the extension. I unthreaded the extension enough for some water to seep/leak out to a fill a bucket. Took 5 minutes to drain the sink and extension such that I can remove the extension without water coming out. There is water at the top of the tee and does drain slowly. After about 5 minutes I could not feel water with my finger by sticking it into the tee. Leaving the AAV and extension removed, I ran some water to see if it would drain now, and it did not. Fill back up quickly, and spilled out the tee.

I ran a snake about 25feet through the open tee and did not have any effect (still can touch water with finger in the open tee.

I did take a peek in the crawl space and the drainage pipe maybe was altered by the guys whom repaired my hvac. Seeing a slight decline and then incline prior to doing a 90 turn/elbow. I estimate this was about the distance I ran the snake (got stuck at the elbow).

See two pics of decline and incline prior to the elbow. Could this be the culprit? Seems subtle. I like the idea of a cleanout in the crawlspace or another AAV? Otherwise I need a longer snake!

Nick

 

[John Gayewski]

You need to snake the entire run.

 

[Reach4]

Consider getting a drain cleaning pro with bigger equipment. This equipment can be dangerous.

 

[Nicho247]

A follow-up/status update. I did cut the pipe a little before where the elbow turns on that recent picture. Installed another AAV and also a cleanout. Got a bucket of some nasty drainage water. Based where this water was accumulating and a visual line of sight from the crawl space to a sink that has no issues. Concluding with either a blockage somewhere after the 90 turn or the slope is messed up from the recent HVAC guys rework. A couple of sections have dips from the HVAC crossing the PVC.

I think I am ready to phone a friend to clear the suspected blockage or evaluate how to fix the slope issues.

thanks all for guidance thus far!

 

[Jeff H Young]

If you need a clean out add one. but adding more AAV 's isnt the fix

 

[Nicho247]

Quick update - running a snake fixed the problem. 6 months inactivity was enough time for whatever crud was present to solidify. Blockage was further down drainage pipe but prior to mudsink. I did put the AAV extension back into place to prevent air locking.