Smell from stack pipe in flat

[Dan]

Hi, I live on the first floor of a 6 storey block of flats. For months now, there has been a bad smell coming from the stack pipe - the smell fills the whole flat, but it does appear to be coming from the stack pipe as the smell seems stronger around there and seems (we think) to get stronger when there is water flushing through the stack pipe.

After 6 months of pushing the property manager to do something about it, they finally sent round a drainage company last week who 'flushed' water through the stack pipe and apparently performed a CCTV survey. They didn't find anything unusual, but said if the stack pipe was the problem that this should fix it.

Unfortunately, a week later the smell is back.

I don't understand anything about plumbing/drainage so am a bit lost as to what to try next.

Any suggestions as to what the issue could be and how to resolve it would be hugely appreciated!

[micky]

What's a stack pipe?

Can you cover it? Would that lessen the smell? Does it lessen the smell?

[gfretwell]

Is it all the flats or just yours? You may have a venting problem in your flat that is sucking all the water out of one or more of your traps. Get a torch and look down each drain, You should see standing water there. (for you US guys I attempted to translate into UK)

[Marilyn Manson]

The only way to see standing water by shining a torch down a drain is if the trap is directly beneath the drain. I have at least 3 drains where that is not the case. Kitchen sink with garbage disposal, a two tub utility sink and the bathroom tub where the trap is at the bottom of the overflow tube, not under the main tub drain.

In addition if a trap was empty, I would suspect that the odor would be strongest near that drain, not near the stack pipe.

With all of that said, I don't quite understand how an odor could come from a "stack pipe" inside a dwelling.

"A stack is described as the vertical section of a plumbing drainage system of soil, waste or vent piping rising through one or more stories of a building. The stack is the largest vertical pipe into which all the horizontal pipes either drain or vent."

The stack typically extends through the roof of a building and is open at the top.

In order to have a "bad smell coming from the stack pipe" I would think that the stack would have to be open in the apartment in question and I can't think of a possible reason - in a properly plumbed building - why a stack would be open in a first floor apartment.

If there was damage to the stack or a bad connection and negative pressure in the apartment that could cause a odor. IMO any opening in the stack, whether caused by damage, wear and tear, a leaky cleanout, whatever, removes the "properly plumbed" status.

[Anonymous]

Is it possible that the smell is not from the stack itself, but is rising up "around" the pipe in what is known as the "pipe chase" Since a stack usually runs top to bottom up a building in that space, the smell might be coming from another flat. Maybe someone cooking "ethnic" foods, or cooking up illegal drugs (aka a "meth lab").

[micky]

I guess a stack pipe is what I thought it was. Like the others, I don't know how a smell can be coming from it. Maybe the OP is using the wrong term.

[trader_4]

I don't either, assuming it's what it sounds like it is, which is the main drain waste pipe serving the apartments top to bottom. Not without leaking at least. If it's just a vent pipe, then it could be leaking gases without leaking waste water. Maybe it's something else, eg a dead animal? I suppose it could be leaking between floors though, where you can't see it and it;s not enough to make it's way further, but I think it's unlikely.

[Marilyn Manson]

As I assume you know this, but for those that may not...

Many "stacks" are a combination of drain and vent. Horizontal-ish drain pipes enter the stack from fixtures inside the building and the stack takes it all down and out. At the same time, the stack extends up through the roof (typically) and acts as vent, sucking air in as the waste water flows out.

Since there is no trap for the stack, sewer gases can enter and rise up through the stack when it's sitting idle, which is why there is a code for how high above the roof the stack must go.

Therefore, it could be leaking gases even if it's the "main drain" pipe. As I mentioned earlier, a leaky stack (or any pipe downstream of a trap) along with negative pressure in the building vs. the sewer could allow gases into the building.