Maximum depth of bottle gully

[andyscotland]

I have messed up.

 

I laid the underground drainage for my extension as deep as I could (within the limits of fall to the existing drain).

 

But I worked to the wrong height for the finished path surface to the level threshold. The extension is on sloping ground and I think I must have measured from the wrong datum 😬😒

 

So as it stands, the bottom of one bottle gully will be 725mm below finished ground level.

 

It is taking surface water and a shared rainwater/kitchen drain via a downpipe through the grating. The back inlet is not connected.

 

I know you can get 200mm extension pieces. Polypipe say that you can only use one, but I'm wondering if that's for rodding access if you're using both underground pipe connections.

 

I can't find anything in building regs/approved docs that specifically mentions an maximum depth for a gully. Does anyone know if there is one?

 

I've tested and I can just reach the bottom of the trap even at the new depth. It's also only about a metre from the IC and is easily roddable from there. So from that perspective if I stick a couple of extensions on it should be fine.

 

So I'm not worried about it other than getting it past BC.

 

I'm very jealous of people who can "ask the BCO". My council has made clear that they will not be looking at mine until the completion inspection and "it's your responsibility to comply, we can't provide design advice"...

I'd really prefer not to take it up and move the pipe higher unless I absolutely have to. I don't want to disturb the other pipes that run alongside and under the extension, and it's all bedded under concrete slabs as it wasn't deep enough to get the minimum cover.

[Dave Jones]

 

use a normal gulley, 90 out the side into your 1m deep pipe.

 

 

[Conor]

Yeah, mount the fully at the surface and just bring the pipe up. You don't have to worry about solids so a steep fall is fine. On my deep run I had to 45⁰ bends on one gully and at th nother a 45⁰ Y connector.

[andyscotland]

@Dave Jones @Conor thanks for replying.

 

My problem is the gully is already in, at the lower depth, and I don't think I can change that to add a drop to the pipe without quite a bit of hassle. Here's what I have at the moment:

 

The gully can't move horizontally as it needs to meet the downpipe above (not shown). So to add a pair of 90s/pair of 45s to drop down to pipe invert I'd need to break up the concrete capping above the pipe.

 

Obviously can do that if I absolutely have to, but it'd be much easier if I could get away with just putting a second riser between the gully & the top hopper.

[Dave Jones]

In that case wouldn’t worry about it

[andyscotland]

Thanks @Dave Jones