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I think I put a lag screw into a vent pipe.

18K views 60 replies 18 participants last post by  Tdlight  
#1 ·
My wife said the bathroom smells like poop. Sure, enough it did. You could smell a slight sewer smell from an area where I removed a baseboard to install a cabinet. Then I got to to thinking, "did I screw that left lag bolt into the vent pipe?" Well, I think I did, because up in the attic, the vent pipe comes out of the 2 x 4 header about 10" away from where I screwed it in. I am guessing the vent pipe angles up the wall to move around a larger support beam. When I unscrewed the screw, it didn't have a pine smell on the end of it like the other screw.

How can I best fix this blunder?

Plumbers epoxy? I also read that you can screw in a stainless screw with silicone on it, but I'm kind of leaning towards not doing this.... This is a good size screw, about 3/8 in diameter.

Thanks for any help.
 
#2 ·
I'd probably use some epoxy such as JB weld or similar, scuffing the surface of the pipe with some coarse sandpaper to make sure to get a good bonding, and making the repair bigger than the hole.
 
#5 ·
One sure way to seal it would be to take a short piece of 4" PVC about 4"" long, cut it cross ways so a 1/3 section is left, apply primer and glue and stick it over the hole.
Another short Stainless steel lag with silicone on it may or may not work, The pipe is round and the back side of the lag is not.
 
#12 ·
Was the screw removed? If not, and it's just a vent pipe.....then the screw is sealing the hole unless the pipe cracked. I would not expect any smell to come out unless the screw was removed.

You might have something else wrong.
 
#13 · (Edited)
Oh great. I was wondering how that could cause an issue. I hope it's not cracked. I guess I will be able to tell once in there if it was indeed a vent pipe I went into.

The only other things that changed in this bathroom remodel were

1. New toilet installed. Not sure how I could have screwed this up since it is caulked in good and of course a new wax seal that came with the Kohler toilet was used.
2. About 2.5 feet of baseboard was removed so that the new vanity would sit flush with the wall. So behind the vanity's legs the concrete slab is exposed beneath the end of the drywall. There is obviously a drain pipe in this area also where the hot and cold supply valves are located.

I guess it's possible that there was some kind of leak before hand. I can't feel any moisture where the exposed slab is at all.

The smell is not super bad, it seems like it comes and goes and is not totally repulsive. The few times I had noticed it, I figured I was smelling someone's residual poop smells.

Thoughts?

What else could be wrong? Could it be a busted sewer pipe in the slab? Wouldn't that be pretty obvious?

An inspection of the vent pipe in the attic yields no odor as far as I can tell.
 
#14 ·
You caulked in a toilet?...hmmm. I was told to never caulk a toilet.
 
#15 · (Edited)
Yes, of course I caulked the bottom of the toilet. We set it and then caulked the bottom to the tile.

Standard practice I thought, at least in the 3 houses I have lived in and 100's of other people's houses I have been in. :eek:

**edit** I just read that you should leave a small area uncaulked around the back just in case of a leak. I will remove some of the caulk from the back tonight.
 
#16 · (Edited)
Just to add to my above conversation-

There is no sewage smell coming from the shower drain or sink drain.

Sink and p-trap are all brand new.

The smell seems to be coming from the wall where the baseboard was removed, I think. It's hard to tell.

Again, no smell in the attic. I would think if it was a CLOGGED vent pipe, then I would hear sounds in the wall when flushing or washing hands.
 
#18 ·
I think I am going to remove some caulk from behind the toilet first and take a nice big whiff.

Next, I will remove the vanity from the wall and check the lag screw area by removing a piece of the drywall then take a big whiff there.

I can't wait.

Nothing beats sniffing for poop odors.
 
#20 ·
Yeah I was planning on picking up a new wax ring and some JB Weld before returning home tonight.

I would assume I will smell a problem right away once I remove the caulk from the back of the toilet.
 
#22 ·
Hate to break it to you, but you must open the wall and repair it properly with a new piece of pipe. Maybe using repair/slip couplers.
What are you doing using 3/8" lag screws to hold up cabinets?!?
Find the studs and do it right with the proper screws or anchors next time.
If you used the wax ring that came with the toilet, then there is an 80% chance it is the wrong one and is not sealed properly. Take the toilet up, study/measure the situation and use the proper thickness of wax. The wax ring should compress a substantial ammount to seal well but not so much that it fills up the drain line and swells way out. Study it. They are cheap.
Caulking of toilets- A very contentious subject!! I or any of my plumbers liked it or have seen a need for it, but have had city and home inspectors require it. Maybe don't do it untill you get all your other stuff taken care of, giving you the chance to be sure its sealed properly.
 
#27 ·
Ok, so I just finished sniffing for poop smells.

I sniffed around the exposed slab behind the cabinet, I sniffed behind the toilet, and then I scraped a few inches of caulk (it was a very thin layer), from the side of the toilet and took a big whiff there. I sniffed really hard at the shower drain, and then the sink drain. My poopometer smelled nothing. Absoutely nothing.

I'm at a loss here. Maybe my wife farted last night when she told me to check it and just didn't want to admit it.
 
#29 ·
just my 2 cents....what kind of cabinet did you install with a 3/8" lag????? if you screwed that into the pipe ..my guess it cracked the pipe..that is way to big of a screw to hit a pipe with... open up the wall and you will see what happen..
 
#31 ·
It's only a 28" wide vanity with a vessel sink on it. I probably should have just used some long drywall screws in retrospect.



The million dollar question is why is there no smell? I guess I need to go take a dump in another toilet and start sniffing again. Problem is, I already went twice today.
 

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#33 ·
Are you telling me theres wood at those corner braces? Did you install backing before wallboard? Is that where the studs fell?
Those look like Stainless steel Wood screws, about size 8x2 1/2 I thought you said; you used a lag screw?
Sorry to ruin your day but can't you use the proper trap? I don't think those are acceptable to IRC 2006
Can't you chisel out an inspection hole in the wallboard to prove whether you hit it or not.
Usually there is a rail along the back of a cabinet that, after locating your studs, you screw drywall or wood screws into. Usually before the top is set.
You really need to remove that toilet and be sure it installed properly.
 
#36 · (Edited)
The vanity came in one piece. The right side corner brace drilled directly into a stud. The left one I had to angle a little bit to the left to hit what I thought was a stud (still could be one). I found the "studs" using a stud finder. Where I screwed in on the left falls at about exactly 28" from the right side. Since the right side is that 45 degree angle, I figured the 16" on center rule doesn't always apply.

The vent pipe where it pops out of the 2 x 4 in the attic is directly centered behind the toilet. It then of course runs up through the roof.

Are vent pipes normally installed straight and up? Does anyone have a pic of how one would branch out and connect from the shower, sink and toilet?

I think the toilet is set fine. The wax ring that came with this Kohler toilet looked almost identical to the Oatey "10-year" ring I just bought from Home Depot. Plus, I can't smell any odor at all from under the toilet when I stick my nose right on the base where I dug out the thin layer of caulk.
 
#37 ·
If you are saying there is a stud at both sides of that cabinet, then there would be one centered between them..............Right where your drain stubs out.
Carpenters don't use "Stud finders". Find your studs and be sure of where they are. Use a finish nail where something will be covering. Along where the screwing flange on the cabinet is.
Size 10. There are about 5 different sizes. I have seen where two are needed. Every situation is different and it should be understood before installing a toilet.
 
#38 ·
Yeah, something is definitely not right in this bathroom. It doesn't smell like 'poop' per say, it just doesn't smell fresh when you walk into it. My other bathrooms do not have this same odor.

I will reseat the toilet first thing tomorrow and then if that doesn't do it, pull the cabinet back and remove a small piece of drywall and see what's behind it. Or vice versa, I need to think about this.
 
#48 ·
yeah you'll need to cut into the wall and extend the pipe properly.

Did you retile when you did this remodel? It could be the toilet flange is sunk below the tile and the toilet isn't properly sealing against it.

What was the old vanity like that you removed? Was it leaking? Maybe mold is growing behind the baseboards or on the drywall, and when you cut the piece of baseboard off it released the odor.

Is that a new mirror also? The smell didn't have to generate from the screws from the new vanity. Maybe when driving in the anchor for the mirror you hit the vent pipe? Makes more sense to me since you say the vent pipe is right behind the vanity, straight up the wall
 
#54 · (Edited)
Follow-up to original issue-

I reset the toilet with an Oatey 10-year ring from Home Depot. Honestly, it was pretty much the same thing as what came with the Kohler except that the Oatey had a black plastic flange on it that the Kohler did not. Turns out this was unnecessary as there of course was no leaking going on.

Then I removed the vanity and cut out a 2" x 2" square of drywall where I thought I may have hit a vent pipe. I had not. It had hit a stud.

I think it's the new toilet that has the weird smell. That or a combination of the new stainless steel tile on the wall.

At any rate, it's definitely not the sewer vent for this bathroom. I even stuck my nose all up in the sink drain coming out of the wall and I can't smell a thing. Weird.

All this for nothing and now my toilet rattles when I sit on it. ****. Now I have to go buy some clear shims to stuff in on the right. It's probably a 1/16 inch rattle when I sit on it.