Kitchen sink drain to gully?

[seanblee]

Thanks to my builders (who have since gone bust and left me to pick up the pieces), no internal waste pipe was allowed for the kitchen sink in my new extension. Rough drainage layout is as below, where green is the original main drain run (shared with next door, flowing left to right), blue is original drainage and red is new (again, blame the builders...!). The blue dotted line shows the original outfall from the soil stack, which had to be moved to make way for a pile. Everything underground is 110mm plastic.

 

 

At the moment, the red pipes sticking out to the north are capped, but these are intended to be inspection chambers (condition of the build-over agreement as we had to remove two). The construction under the extension consists of six piles, 250mm reinforced concrete slab, ~250mm concrete infill, DPM, 100mm PIR topped with 65mm screed embedding UFH pipes, so I don't see any possibility of going down - I think my only option is going to be an external gully with 40mm through the kitchen wall, but I'm interested to hear if anyone has any other ideas! If I do have to fit a gully, I'm thinking I'd be best running the pipe across to the right-hand inspection chamber so the flow doesn't have to make a 180-degree turn - does that sound OK? Having never done this before, I'd appreciate any tips on how to make sure it works and doesn't look completely awful...

 

Many thanks in advance for any advice!

Sean

[markc]

I would be going through the wall and drop into the red line. Although if a sink was always going to be there then no reason UFH pipes should be in that area so you could go down but messy going through the slab and insulation etc.

[Olf]

4 hours ago, markc said:

I would be going through the wall and drop into the red line

Me too.

Make a gully, add a garden tap above (fed from the sink supply) and disaster turns into success

[Temp]

+1

 

Unless they specified a particular Inspection chamber you might be able to combine the two into one unit. May also depend on the depth of the red pipe.

 

Google Bottle Trap Gully..

 

https://www.jdpipes.co.uk/knowledge/underground-sewer/what-are-gullies-and-where-do-you-need-them.html

 

 

Bottle Trap Gully

The bottle trap gully works in much the same way as the P trap, but the change in design solves the rodding problem. Unlike the P trap, the bottle gully doesn’t require the tight bend in the pipe to trap the water. Instead, it uses a removable inner sleeve (or central chamber) that creates a space between itself and the wall of the gully that the water is forced up to reach the outlet pipe. This design still traps the water to use as a barrier against smells and gases, but it does so with a removable sleeve that makes cleaning out silt and debris by hand much easier and also provides direct access to the outlet for a drain rod in case of a blockage in the drain - though this can depend on how deep the gully has to be installed to and whether it requires the addition of a hopper and riser to reach the surface.

 

[Oz07]

Roddable gully for me. Osma do a good one where you will still be able to pull trap out if using solvent weld. Otherwise use push fit on the 40mm. Doesn't matter about changing directions if your going vertical down into the gully. The water isn't going to remember what direction is was going before dropping. 

[SteamyTea]

4 hours ago, Oz07 said:

The water isn't going to remember what direction is was going before dropping

Many homeopaths may disagree with you here.

[joe90]

I dislike external pipes on houses and on my new build we put a gulley outside but the gulley had sockets for 50mm pipe below ground level so I installed a 50mm pipe from under the sink, down into the floor, then out through the wall below ground level onto the gulley socket.

[Temp]

6 hours ago, joe90 said:

I dislike external pipes on houses and on my new build we put a gulley outside but the gulley had sockets for 50mm pipe below ground level so I installed a 50mm pipe from under the sink, down into the floor, then out through the wall below ground level onto the gulley socket.

 

+1

We ran 110mm under the floor to the sink area but I think it's too late for the OP to do that.

[seanblee]

Many thanks all - managed to core drill out for the 40mm today and feed it into a temporary run, so I'll get a roddable bottle gully and see how I get on with installing it! Looking at a rectangular hopper so I get a section to feed the 40mm into as well as a removable grid.