Covering Previously External Drain Access

8 Sep 2014
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United Kingdom
Good Afternoon All,

I hope this is in the most appropriate section, but apologies if not.

Long before we bought our house the property was extended to the side, over the previously external manhole covers and an open exposed drain. The kitchen sink waste comes through the old external wall and drains into the open drain, as does the washing machine and dishwasher. The open drain feeds into the main drainage for the house, accessed via the manhole covers.

However, this drain is no longer external and therefore would like to tidy it up.

What are the options for covering this open drain? I assume access will still need to be maintained in case of blockages in the future (but maybe not) but I am unable to find anything suitable on the web to do so. Ideally some kind of surface manifold that I can connect the sink /dishwasher/washing machine waste into would be a neat solution. Something that sits flush with ground level would be ideal to, but only from a visual point of view.

The open access drain is ~4" square (~5" below ground level), before widening ~0.75" all around at a small step then tapering up to ~8" at ground level.

Any help or advice would be greatly appreciated. Thank you in advance!
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How about a 4D900 gully with a 90degrees bend in the back to make the gully a back inlet?

You could drop the waste pipes into the top on the 90 and swap the gully top for a 4D660 at ground level.

You should see what I mean isn't you google those bits.
Hi Ian,

Thanks for the help and the link. Sorry but I don't understand what you mean? I cannot see how what you have described would help, but maybe it was my poor explanation!

I have (hopefully) attached a couple of pics with this reply to show the drain, which should help any further advice.

I should also add that I don't really want to get involved in any digging/re-arranging of the drain itself, more a simple cover to close it off and tidy it up.

Thanks again.


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You have to seal the gulley or risk vermin possibly entering your property.

Why not measure the gulley opening dimension or make a cardboard template, & take it & a pic to your local plumbing or builder's supplies.
They will fix you up with a gulley grid.

Cut the pipe stubs that point down to just above the gulley opening, and then slip in the grid so that it rests just below the cut stubs.
Hi Vinn,

Thanks for the help.

A grid would still mean the drain can vent to the space above ground though, which I ideally want to prevent. It is a garage, but it still occasionally has a foul smell.

I assume it will be ok to seal off completely?
The gulley is not a vent and doesn't vent anything.
If it originally was a yard gulley then its almost sure to have been trapped - is there permanent water in the gulley?
Cleaning out any trap sludge often helps with removing smells.
Its unlikely but if there is a sewage problem in the gulley drain line then the place to start investigating would be from the manhole.
After trap cleaning you could run a hose down the gulley past the trap to "jet" the drain line.

Its not OK to completely seal the gulley off - you are obviously still using it.
Hi Vin,

I understand what you are saying. I'll take a closer look tomorrow to see if there is water trapped in there. I guess the smell could be coming from any waste that is floating at the top/collected at the top around the edge of the gulley. After all it is direct from the kitchen sink/dishwasher, so not everything will make its way through the trap.

When I said about sealing it off, I did not mean literally. It obviously still needs the 3 waste feeds going into it, but they could be sealed to the 'cover' and the cover in turn sealed to the gulley edge.

Or is that still not possible? Does it need a vent for the trap system to work?
The manhole, and the soil & "vent" stack provide any necessary venting.

You could make a template from a ply offcut and silicone seal it to the gulley rim.
The pipes would have to be cut, rearranged, and let into the ply cover.
The pipes would then have to be re-connected.

All pipe stubs should be let down into the gulley and stop above the trap water - you dont want waste water swirling around the gulley recess as is happening now.
Hi Vinn,

I realised after I posted that the main vent stack and the waste within the sink itself will be vented, so no need to worry about the vacuum.

Your suggestion about ply template with the pipes fed in is fine and will be easy to make.

I guess theres no off the shelf solution available given no one has recommended one?
You will have to make something. You could alter the pipework to make it easier, e.g., join the 2 pipes on the right so you have 1 less going into the gully.
What are peoples thoughts on blanking the gulley off a few inches below ground (allowing for waste pipe holes) and screening over? This would give a neat visual solution but would make access in future almost impossible.

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