What did I put a nail into??

[Wade Lippman]

I went to hang a picture today in my second floor bedroom. The stud detector showed a really wide stud, but I was skeptical because of the width. I found normal looking studs on either side, 16" apart, so this shouldn't be a stud. I checked the other side of the wall, in a bathroom, and came up with the same thing; two 16" apart studs with this extra wide thing in between. It runs the whole height of the wall and isn't near the shower and there are no heating vents near it. I ran a metal detector over it with no results, though it did find the screws in the nearby studs. I ran a device that is supposed to find electrical wires; it found them running up the neighboring stud, but nothing on it. I looked on the first floor and there is nothing down there; no chimney, water heater vent, or anything else.
I decided to avoid it and put a nail in to the side of it.
Then I had a senior moment and proceeded to put the nail into it. Argh. Well, the nail wouldn't go in much past the drywall. Whatever it is, it is hard.

What could it be? (I am so hoping that trying to put a nail in didn't damage anything!)

[Tom M King]

Maybe a PVC or ABS vent pipe for the plumbing system.

[Dave Zellers]

I vote for a vent pipe. Can you peek into the attic at that spot?

[Dan Barber]

How old is the house and what is the location of the wall? Exterior, interior? House construction? Brick, wood sided, vinyl sided,etc?

[Bill Howatt]

If there is a first floor bathroom under the second floor one, then I'd say Tom's very likely right. If not, he may still be right. You could go outside and see if the plumbing vent stack is about in that area, unfortunately, it doesn't have to be located right above the pipe but it could be a clue.

[Jim Koepke]

In agreement with those who think it is a vent stack for the plumbing. Depending on when your home was built, it could be vitreous clay, PVC, ABS or even iron/steel.

jtk

[Tom M King]

I worked on a 1933 house that had copper DWV pipes in it.

[Wade Lippman]

Maybe a PVC or ABS vent pipe for the plumbing system.

Interior wall, built in 2006.

There is an attic hatch about 10' from the "thing". I am too old and fat to actually go up there, but could see a PVC vent pipe coming out in the approximate area. It is right next to a bathroom and above the laundry. So, I figured I had the answer. I probed with a wire and found it to be solid immediately below the drywall. I then tried to hammer a nail into a piece of pipe and found it only left a little mark. So all is well.

BUT, I tested my stud finder on a piece of drywall and a PVC pipe. The stud finder doesn't see the pipe!
If the pipe was attached to a sideways 2x4, the 2x4 would give the wide signal I got, but then I should have been able to drive the nail into the 2x4. And if it was flipped around so the pipe was next to the wall, the stud detector wouldn't register it, and the 2x4 would be too far away to register. So I am still confused.
-----------------


Perhaps my OCD is showing, but I wet the inside of the pipe and now the stud detector sees it! Perhaps the vent has humidity in it which shows up? What size is the pipe likely to be? All I had was 1.5", but the vent looks like it might be 2", which might account for wide signature.

[Tom M King]

2" or 3" PVC most likely.

[Mike Soaper]

Nail stop plate? to stop nails from going into pipes or wiring.

Simpson Strong-Tie NS 1-1/2 in. x 6 in. 14-Gauge Nail Stop NS2 - The Home Depot

[Maurice Mcmurry]

One of my gripes against nail guns is that the operator has very little hand feel while nailing things, much like Cupid "He don't take aim he just Bang Bang Bang". Good job being attentive and following through with care Mr. Lippman. I think it is a drain or vent pipe too. Hopefully not punctured. Probe around through the nail hole with a hat pin to investigate.

[Dave Zellers]

One of my gripes against nail guns is that the operator has very little hand feel while nailing things

So true. I used to walk on a job site and see 3-4 rafters where at least half the nails missed.

[Wade Lippman]

I looked in the attic again, and the vent pipe definitely come up from the wall in question. While it's exact location is hard to determine, it has to be within a foot of where we think it is; so I think it is pretty certain that I found the vent pipe and tried to put a nail in it. My 1.5" pipe doesn't give as big a signal as I saw, but a larger pipe would. It feels solid when I poke it with a wire; so I am pretty sure I got away with my carelessness.

But I have two questions:
1) My stud detector doesn't see a PVC pipe unless I wet it. Is it fair to assume a vent pipe would be wet from condensation when it is 30F outside?

2) I am confident I did no damage, but how would I go about removing some drywall to actually see the pipe? I would just use a drywall saw if it wasn't for the pipe, but I obviously don't want to damage the pipe. (I've tried a dremel, but found it really hard to control.)

[Tom M King]

Don’t worry about it unless a problem arises. I doubt you will hear from it again.

[Dave Zellers]

Wade: "I went to hang a picture today in my second floor bedroom."

The nail you would use to hang a picture on the wall will bounce off a 3" PVC pipe. No worries.

As you also said, 'it wouldn't go in past the drywall'.

The moisture thing is odd tho...