Misaligned drain causing headache

[tambourineman]

Hi there,

In the process of renovating the back garden which involves lifting the old driveway (runs the length of the side of the house) and re-laying it with new slabs. In doing so, I’ve come across a bit of an issue with the rear drainage. This grid takes a mixture of gutter rainwater, kitchen waste water and upstairs WC bath/sink waste water.

As you can see from the first picture, the circular aperture on the underside of the grid has been grossly misaligned with the circular drain in the ground. It’s off by at least an inch and a half. More worrying is the fact that it’s completely open – the grid is sort of suspended by the concrete and house bricks above the drainage system – so all the waste water spills over into the surrounding clay and, presumably, the brickwork and foundations of the house.

The gulley that you can see (in the third picture) with pooled water in it is due to the fact that I removed a piece of drainpipe that had been buried, with one end stuck between the grid and drain, and the other end supposedly providing a run-off for the patio area (it was useless as the pipe was full of clay). Total bodge. Occasionally, if the drain ever gets blocked, the kitchen begins to smell.

How do I correct this? My thought was that I’d replace the grid that collects the assorted waste water and make sure that it actually funnels the water into the drain. I assume there is a metric-to-imperial connector that would do this? I’d probably need to excavate the surrounding concrete to align it properly, before re-filling the gulley with concrete to secure it in place?

Any advice would be appreciated.

Untitled

• tambourineman
• 28 May 2011
• 1

Untitled

• tambourineman
• 28 May 2011
• 1

Untitled

• tambourineman
• 28 May 2011
• 1

Untitled

• tambourineman
• 28 May 2011
• 1

 

[Hugh Jaleak]

Personally i'd look to removing the entire gulley and replacing it with a plastic gulley. If you carefully excavate and expose the drain back to a clean section of pipe, you can (very carefully) cut the drain and fit a suitable collar to convert to plastic.

Fernco are one manufacturer of such collars, Wickes also do something similar. Once connected to plastic, fit your new gulley, bed and haunch it with concrete to secure it in position.

I'd look to fit a 'bottle' gulley. This type have the added advantage of allowing rodding access from the gulley, and may not require bends to align the outlet to the existing drain.

The 'Osma' bottle gulley has side boss connections, with a 110mm 90deg bend and an adaptor the black downpipe could be accomodated to enter the side of the gulley. This may help avoid water splashing onto the surrounding brickwork.

 

[tambourineman]

Cheers for the reply.

Unfortunately, a bottle gulley may well be out of the question as it would raise the ground level too high. Besides, the existing drain has a trap system built in.

Based on your suggestions, I've narrowed down a few products that will work. Will most likely fit a rectangular hopper with a spigot adaptor.

I quite like the idea of having a separate inlet for the downpipes and kitchen waste (as you correctly pointed out that splashing is making the corner look unsightly), but will probably have to have a think about how I could connect that, given the small amount of vertical space available.

 

[Hugh Jaleak]

To give you an approximate idea if it helps, the existing gulley has a trap under the hopper, so the invert of the connection from gulley to drain will be at about the level of the water in the gulley now. Invert depth on the Osma Bottle gulley is approx 220mm. (I would suspect you may find the bottle gulley would actually sit lower than the existing arrangement.)

 

[blockeddrainleeds]

HI i agree that replacement is the best option you need to carefully excavate area to give you access to the clay pipe to an undamaged area.

You may find that it the clay pipe has a collar on it with external diameter of nearly 8 inch you can get a flexi seal to adapt these down to 4 inch plastic pipe.
I normally cut the collar off to give me a cleaner flow using a diamond blade in an angle grinder.
I then use a flexi seal to join from clay pipe to plastic 4 inch pipe then backfill space using shingle to accommodate new bottle gully or p trap gully

you will need the following

http://www.drainageonline.co.uk/Gullies-(110mm)/Roddable-Gully-with-180mm-diameter-Round-Top.htm
http://www.drainageonline.co.uk/Gullies-(110mm)/Gully-Raising-Piece.htm

http://www.drainageonline.co.uk/Flexseal-Couplings/Flex-Seal-Adaptor-Couplings.htm

give me a shout if you need any further help

 

[tambourineman]

HI i agree that replacement is the best option you need to carefully excavate area to give you access to the clay pipe to an undamaged area.

You may find that it the clay pipe has a collar on it with external diameter of nearly 8 inch you can get a flexi seal to adapt these down to 4 inch plastic pipe.
I normally cut the collar off to give me a cleaner flow using a diamond blade in an angle grinder.
I then use a flexi seal to join from clay pipe to plastic 4 inch pipe then backfill space using shingle to accommodate new bottle gully or p trap gully

you will need the following

http://www.drainageonline.co.uk/Gullies-(110mm)/Roddable-Gully-with-180mm-diameter-Round-Top.htm
http://www.drainageonline.co.uk/Gullies-(110mm)/Gully-Raising-Piece.htm

http://www.drainageonline.co.uk/Flexseal-Couplings/Flex-Seal-Adaptor-Couplings.htm

give me a shout if you need any further help

Yeah, there is a collar on the pipe that makes it huge. 8 inch sounds about right. I spent ages trying to find some form of adaptor that would stretch to fit it, but to no avail.

I really didn't want to have to remove all the concrete casing around it (let alone cutting the damn thing), but I can see that what you guys are suggesting is the better option.

 

[Hugh Jaleak]

Final decision is yours, but its worth noting that all the water that isnt finding its way into the gulley (and then away through the drains) is going into the ground next to the base of your house wall.... Not an ideal situation, and could come back to bite you if not dealt with properly.

If you dig back and expose the pipe leading away from the gulley, you should be able to find a clean section of pipe, then choose a suitable point to cut it. Once the pipe is cut (carefully!), then the existing gulley is basically 'detached' from the drain and can be broken out if need be. Once this is removed you can excavate as necessary to accomodate new gulley.

Chamfer cut end of the clay pipe, fit your adaptor, cut a piece of plastic pipe to appropriate size, and assemble. Bed, and support new gulley with concrete, fit a gulley surround if desired and make good/bench gulley surround. Important matter is getting the water into the drain and not into the foundations of the house!

 

[tambourineman]

Hi there,

Thanks for the advice given. I really appreciated the effort and it helped me to make a decision.

I decided that the suggestions made were probably beyond my level of competence. Cutting a pipe embedded in the ground felt a bit risky. As such, I decided to fix the existing gulley by realigning the hopper over the drain.

Made a temporary fix and left it for a few days to see if the area remained waterlogged (wanted to ensure that the existing gulley wasn't leaking).

Untitled

• tambourineman
• 13 Jun 2011
• 1

British ingenuity at it's finest!

After satisfying myself that it was OK, I reset the hopper.

Untitled

• tambourineman
• 13 Jun 2011
• 1

Need to replumb the kitchen paste straight into the hopper. Chances are, when I re-lay the paving, I'll raise the hopper to be flush with the new floor level and use a rubber adaptor.

 

[Hugh Jaleak]

Looks a good job done. If you're not worried about appearance, swap the bend on that waste for a 45deg compression waste bend, and a longer piece of pipe into the gulley. Sorted.