I have a small bungalow built in 1940. A basement bathroom was put in prior to us buying the house. I was just looking through an access door that I can see a small bit behind a wall in the basement bathroom. (The wall was framed over the brick foundation wall and drywall put in.)There is a toilet and a bathtub on that wall. I can see what looks to be an iron pipe about 3 inches in diameter standing about 4 feet in height. All I can see is about a foot of the top. I'm not sure if it is capped or not. It appears to be in between the tub and the toilet.
I am concerned about its purpose. Any ideas what it might be?
I really dont want to have to tear out a tiled wall to find out, but if I have to....
Thank you for any thoughts on this.

 

Sounds like a vent pipe to me. It should go all the way up and tie into the vents that go out the roof but if it just ends maybe it has an air admittance valve as a vent?

 

Since the basement bathroom is an add-on...wonder if they re-used the piping that used to be for a clothes washer?

That 4' pipe would seem about right for the washer drain standpipe...only now as SD said..it's being used as a vent...which is a no-no...

 

It is possible that the washer used to be there. Hard to tell.
So and 'air admittance valve' is not legal?
What would be the danger in leaving it as is if this is the case?
Thank you.

 

No...I didn't mean the AAV was illegal...though in some areas I think it might be. I meant if the standpipe has a trap and the pipe is just open at the top inside the wall...that would be wrong from everything I know.

As to anything else..I'll let a Pro answer. I was just throwing out another possibility...

 

Since we are guessing there is no way to tell what the pipe is.

You have to get a better look at it, sorry.

 

A mirror and a light might show whats on top. Or you could go high tech with a webcam and a light.

 

Thank you all for your thoughts. I will see if we can rig up something to get a mirror over the area.
I'm tempted to just tear the whole wall out at this point. Never know what you're going to find when you open up someones old work!

 

Using a probe such as one made from a straightened coat hanger with a hook bent on one end I'd try to see how long it is. You could then open a small viewing hole at that point.

 

It might be simpler to pay a plumber to come over & tell you what it is rather than tearing out a wall.

It's not inconceivable that you tear out the wall & still won't know what it is.