connecting sink to foul drain without a 'hopper'

[RobertL]

Please can someone advise me how to connect my sink to the foul drain without an open 'hopper'?

Presently my kitchen sink connects into the foul drain via a sort of open "hopper" outside at ground level (what is the proper word for this?). the hopper has a u-bend trap below ground to stop the smells coming up from the sewer.

I want to put a lean-to conservatory over this outside area and I don't want an open hopper in it; I want to have a sealed connection from the sink into the foul drain.

I'm thinking that if I simply make an airtight connection to the foul drain from the sink then I might get bubbling through the sink trap. Would the standard solution be to have a new stack connected to the foul drain and then to connect the sink to that by an access boss?

Robert amateur

[The Natural Philosopher]

So fit an air admittance valve. The foul drain should be vented nearby.

However. Be aware that for very good reasons. any bend in a sewage system needs to be accessible to clear it.

If you are abutting an extension to a kitchen, you have building work anyway: lay new drains properly.

That is, find out where the drain runs TOO, and and remove the 'hopper' altogether and extend the drains STRAIGHT to the nearest outside wall of the new extension, to the sink, and pout a proper chamber there, and then run a STRAIGHT pipe to the kitchen, even in this means carving up the foundations of the existing to get it INTO the kitchen, and then a right angle with adapter down to 'sink' sized will get you a proper setup.

That's possible, but that places it in your extension. Put an AAV on top of it in a cupboard maybe.

[RobertL]

On Apr 30, 6:35=A0am, The Natural Philosopher wrote: > So fit an air admittance valve. The foul drain should be vented nearby.

Interesting, thank you.

yes, there is no bend here.

I don't want to dig near the house foundations (victorian, shallow) but I can dig down to the part of the drain that I want to access.

I won't have an outside wall when the conservatory is up. it will go right to the boundary. but I take your point about doing it all new from the point where is joins the large drain pipe. i will indeed remove the hopper and its connection to the drain.

yes that is very interesting and a much better solution. As the nearest vents are quite close (4m doenstreamer and 6m upstream) the AAV probably will have nothing to do except satisfy the BCO. . thank you very much,

Robert

[Hugo Nebula]

On Thu, 30 Apr 2009 06:35:16 +0100, a certain chimpanzee, The Natural Philosopher randomly hit a keyboard and produced:

If the branch is less than 6m to a vented drain, he can use a stub stack.

[RobertL]

that means a little stack with no vent I presume. Thanks for that. there are two vented stacks within 6m.

Robert