Strange sewage smell coming from behind kitchen sink cupboard

[Pickwickpick]

The point PW is that the AAV will not let foul gases out not that its faulty. The point of a soils stack is to let air both in AND out. If its blocked by a poxy AAV then it WILL come out elsewhere. End of.

If this were my place, then I'd simply take the thing off first. If the problem goes away then get the builder back to repipe it properly to 1m above the nearest opening window as the regs say. AAVs are a rubbish builders bodge.

Yes they're not meant to let foul gases out, but they can if faulty but its a moot point here. Agree with you that they're a crap bodge with potential to cause a lot of headache solely so the builder can avoid doing fitting the soil stack properly.

If the AAV is blocking it and its letting foul air out elsewhere isn't this potentially indicating an issue with the soil stack, i.e. if it can less gases out within the house it could also let waste water seep out? Suppose its prob more likely that the foul air is being forced through water traps due to pressure probs if blocked by aav.

 

[Welder]

If the AAV is blocking it and its letting foul air out elsewhere isn't this potentially indicating an issue with the soil stack, i.e. if it can less gases out within the house it could also let waste water seep out? Suppose its prob more likely that the foul air is being forced through water traps due to pressure probs if blocked by aav.

Maybe. Without knowing all the layout we can't be sure this isn't the only foul gas exit. Designers don't generally put in what's not needed. If it's the only outlet then it perfectly normal for gases to escape elsewhere as sewers need to breathe. Once again we have no idea of runs etc. With so many traps being shallow these days, it WILL find its way out. Just takes more of a build up to overcome a deeper trap.

 

[Steven Southern]

Right so I’ve cut the aav off as it was welded on and I’ll replace that with a bend and extend it up past the gutter as it was before. The pipes are as shown in the pics. I’ve lifted the manhole and it doesn’t appear blocked but I could be wrong. (The debris you can see fell in when I lifted the lid)

 

[Pickwickpick]

Is that standing water in the manhole?

 

[Old Account]

Quite a bit of builders crap in the drains.

 

[Steven Southern]

Is that standing water in the manhole?

It’s moving but slowly. That’s with the kitchen taps on full.

Quite a bit of builders crap in the drains.

Yeah I thought that. The part brick and a bit of debris fell in as I opened the lid and the water is slightly flowing with the kitchen taps on. (Not sure how fast the flow should be)

 

[WC1]

It's not really a question of how fast the flow should be. The fall on the pipe should not allow any standing or sluggish water. There's a blockage somewhere. Clear out that debris. If you've had your dinner and you're up for it, lift the next lid on the run. Watch out for Mr Rat. Enjoy

 

[Steven Southern]

It's not really a question of how fast the flow should be. The fall on the pipe should not allow any standing or sluggish water. There's a blockage somewhere. Clear out that debris. If you've had your dinner and you're up for it, lift the next lid on the run. Watch out for Mr Rat. Enjoy

So I’ve been and bought some rods today and cleared the manhole. Got some old peices of the cast iron soil pipe out the the builder obviously dropped when he was fitting the plastic pipe. Plus a few other odds n hens. Literally. Lol. Now I’ll suppose it’s how long I have to wait before the smell disperses from behind the sink.

 

[WC1]

Well done Steve! Good job. Keep an eye on it, I'd lift the lid again in a few days. If they're your fist set of rods remember to always turn clockwise. Always clockwise

 

[Sharp Point]

Couuld be the the 'builders bodge' aka an AAV? Why oh why don't they do things properly and let the darn thing breath as designed...

Builders know how to do everything..... don’t you know that YD