What is this item called - drainage

Gully trap, gully drain, or similar terms on a picture search should get you there ...

Brilliant, thanks!

One of these?

Hepworth Supersleve Housedrain P Trap Square Gully 100mm

Same sort of idea, apart from the lack of a separate entry for the wash basin drain. From what I can see by lifting the plastic cover, it seems to slope across towards the basin waste pipe, the deeper it goes down.

In message , Harry Bloomfield writes

er.. isn't this likely to be a *back inlet gulley*?

regards

I have a plastic one with an inlet for the bath. I think it's been used because if the bath drained into the top of it, there would be no fall on the pipe. This plastic one has a piece of plastic you can pull off which gets you to the other side of the gulley P-trap, for rodding, although I've never needed to try removing it.

Andrew Gabriel was thinking very hard :

This one is clay and there is no rodding access.

Tim Lamb formulated the question :

If you stand facing the house wall, the square plastic cover is on the left tight against the wall, the basin waste enters to the right of that square, with no obvious connection to the gulley.

If you remove the lid and look in, the left and right hand walls of the gulley slope in from top to bottom towards the waste pipe on the right.

The outlet obviously goes to a manhole which is behind you when facing the wall.

I may be able to get the SDS out tomorrow and dig down for a better look.

Back inlet gully:

Its a "gully" - there are several different types depending on exact requirements.

As other replies have said, it will be a gully. I don't think today's designs will necessarily look identical to your old one, but they will do the same job. I would think that plastic would be easier to work with than clay.

The gullies sold by Toolstation, like this:

Screwfix sell back-inlet gullies, like this:

However, it sounds as though the one you have is not a back-inlet gully and that the sink outlet joins the hopper, rather than lower down in the gully.

Like this:

If you bought the hopper, you could connect it to a trap, such as:

I had a blocked clay drain caused by some sort of cement setting in the bottom but I tapped the deposit with a piece of scrap wood. I was lucky that I was able to break the cement up without breaking the pipe. Then I removed the broken up pieces by hand. Perhaps you might be as lucky and would not need to change anything?

HTH Stephen.

Is your bathroom on the ground floor?

Also, brick acid (hydrochloric acid) should dissolve cement or concrete slowly, without attacking glazed ceramic. But your geometry may not be favourable and you may need a lot of it.

Stephen brought next idea :

All sorted now and thanks for the help and ideas.

Once I had dug down to it, it turned out to be a double gulley with a separate trap. They gulley was like a Y shape (two entries side by side), discharging into a separate trap. I only had to dig out the gulley part, which then gave me enough access to the much deeper trap. The mid part of the Y and the depth was restricting my access. I actually managed to clear out the what had once been concrete blocking the trap and all is flowing smoothly again.

I scooped out quarter of a bucket of gravel from the trap.

I tried brick acid several years ago, leaving it to soak unused for a month and it seemed not to shift it at the time. I think that after all it may have dissolved it, but left the trap still blocked with the aggregate. The depth of the trap and the gulley was such, that it made it not easy to properly check. I could only just touch the bottom with my finger tips.

An aqua-vac pushed into the trap sucked lots of gravel out, after which it ran free.