How low can the durgo go? What could go wrong?

[Safety First]

Planned to work out some leadwork voodoo to get this soil pipe through the polycarbonate roof...

Then remembered durgo valves!

But, must be 200mm above highest point of water exit. Which is sink overflow? (One bathroom, no tank in loft.)

1. What if I can squeeze a external durgo on top and under the polycarbonate? What goes wrong?
2. And is there any advantage if I still have to go through the roof with soil pipe, to putting a durgo on a shorter stub of soil pipe?

I saw a proprietary 110 flashing slate today and the rubber part alone won't get between the soil pipe and the wall.

 

[^woody^]

What goes wrong

Your house will smell of shiite

 

[Safety First]

Your house will smell of shiite

There's that, yes...
Suppose I mean *why* does it need to terminate 200mm above highest indoor outlet?
Is it in case the whole lot fills up, it would start coming out of the durgo.... But then it's a valve?

If I can understand why a rule is there I am more inclined to go along with it.

A durgo valve would cost me about £35. A total bargain against having to run that bloody great soil pipe up through the polycarbonate.
Though not sure I can squeeze one in that gap under the polycarbonate.

Are you saying the durgo wouldn't work at all at a height lower than spec, or in case of X then Y would occur.
If you know, just say, please

 

[ironsidebod]

£35? Where are you buying yours?

Having had one fail, I can attest to the smell of ****e and the ball ache of breaking into spaces cos it's hidden!! I'm not qualified to suggest how you do it but save yourself a lot of arseache and do it properly.

 

[Safety First]

£35? Where are you buying yours?
.

Some even cheaper..
https://www.screwfix.com/p/mcalpine...Rj4Y3DZi7xpgTvQSeQbmiUDfg3PhweWAaArnHEALw_wcB

 

[Safety First]

Having had one fail, I can attest to the smell of ****e and the ball ache of breaking into spaces cos it's hidden!! .[/QUOTE

Thanks for the input.
I am all about learning from others' experience.
This pipe terminates above polycarbonate roof of a lean-to shelter. Drying some clothes. Drying some logs etc. Maybe I'll put durgo below polycarbonate. Maybe not. I am asking if anyone knows what and how it goes wrong if durgo is too low.

I can tell people not to file the depth gauges down too far on their chainsaw. I can tell them exactly what would happen and how if they were to ask, "yes but in what way and under what circumstances would the depth gauges thing be bad?"

Clearly Woody is an informed and experienced contributor, which makes the sporadic 'from the back of the class' one liners, devoid of key info, a bit of a tease when you think you might be gifted something useful.
But "your house smells of shiite" doesn't cut it...

 

[23vc]

I believe it’s due to spillover levels, as you say. Not aware of any other reason. Can you route a vent pipe out of another adjacent wall to avoid going through the roof? That’s what I did on my most recent one

 

[^woody^]

Here's my Sunday gift.

You can't just go firing a AAV in any old random fashion on a pipe just because you want to save some work.

You can get type A and B AAVs, and the type A can go below the spill over level. One of the reasons for the height is due to the potential for the stack to be blocked. Another is that the valve just won't work before the trap gets evacuated, hence the house smelling of shiite.

So it's not just a case of bunging a valve on because that's what you've seen on YouTube, but more a case of designing the pipe run.

The OP adds confusion anyway as it refers to a separate soil pipe going through the roof. So why are there two soil stacks?

 

[Safety First]

I believe it’s due to spillover levels, as you say. Not aware of any other reason.

I think you are spot on there. Thanks.

.... Went further searching and found this...

https://community.screwfix.com/thre...ce-valves-permitted-position-and-types.65303/

Very similar content another person chasing the details of the matter to permit an informed choice.


I have just bought and and fitted an external type. Four flushes in all seems well. I can always remove the Durgo, cut through the polycarbonate and insert 2 m of soil pipe- put things back to how they were before. Now that I (think I) know the issue is not one of levels, nor air pressure- in the instal I have done at Ieast, I can continue the roof without having the soil pipe come up through - huge saving in time and challenge for me.
If while watching YouTube/learning DIY my house suddenly smells of shiite I will report it to inform others. Absent such confession, please assume it works fine.

 

[Safety First]

It is still working just fine.Btw.

 

[Safety First]

Update...
I noticed a terrible smell coming in the lean to shelter. The AAV sat atop the soil pipe and was a couple inches below the polycarbonate lean-to roof-The one I had planned to cut through to extend the soil pipe up to the proper height,...until Durgo ideas, at least.

I took apart the Durgo and cleaned it, though it was not really dirty. It worked same before and after cleaning.

Then I found a stinking bag of fly bait and dead flies that had gotten really hot; one of the excellent Red Top traps.

So, yeah. Update... It's *still* working just fine.