drain/gully joint leak

[Dan42]

Hi,

I'm looking for a bit of advice on the best way to tackle a leaking joint between the gully and clay drain from the kitchen.

Bit of background first; this is an old Victorian house and still has the old cast iron downspout on the back which runs into a shallow cast in channel which in turn runs into the kitchen's gully along with the kitchen waste pipes. I had noticed that the concrete channel had suffered a bit of cracking and that the mortar flaunching around the grid had worn through in a couple places and it was looking like I'd need to cut out a few areas to make good with a bit of patch pointing.

One of those jobs you mean to get round to. Probably 6 months go by and I noticed that an area of the tarmaced path, parallel to the rainwater channel, had started to sink. I've heard the horror stories about subsidence caused by these things washing the subsoil away over time, so I decided to get on with the repair. Started knocking out the broken bits and found that sure enough there was a void below and decided to dig this out to expose the full extent of the problem. Fortunately it isn't too bad and is mostly around the gully pot. I figured two or three bags of limestone down there to fill up the voids and then make a new concrete surround to the gully and redo the affected areas of tarmac. At this point I was assuming that this had all been done but just rainwater getting through the cracks.

However, as I started digging out the loose stuff I started to get some nasty smelling black stuff out from around the gully, so suspected I was also getting stuff leaking from the kitchen waste. After chucking a bucket of water down the gully I could see that it was leaking at the joint between the gully outlet and the clay drain pipe.

I've exposed this as best I can, as can be seen in the photo and I've had a good feel all round the pipe and gully outlet and I can't feel or see any obvious cracks or damage.

It just seems to be that the joint has failed, so I'm hoping that there is some kind of product that I can repair this with rather than having to remove the pipe.

Having had a quick look online I'm wondering if this 2 pack epoxy putty would be right for the job?

Everbuild Stick 2 Epoxy Putty Aqua

http://www.everbuild.co.uk/index.php?route=product/product&product_id=681

Sounds like it might be the right tool for the job, I figure I can just stem it back into the joint all round the pipe, but I don't have any experience with drainage, so I'm open to advice on if I'm going to be going about this in the right way.

Cheers,

Dan

 

[Nige F]

Can you post 2 more pics. 1 further back showing the wall + pipes and 1 showing the joint of the gulley/pipe. from the right of the photo posted paralel to the wall looking at the hidden part of the joint

 

[Dan42]

Hi thanks for your reply.

I'll take some more shots of it in daylight tomorrow.

Cheers

 

[ree]

i can see where Nige F is going: the gulley spigot doesn't seem to have been sealed (or fully filled) with mortar into the pipe hub - usually a rim of compo can be seen.

OP, if its convenient, why not completely dry out the gulley - inside and outside, and lower the soil in that hole and remove all water. The bedding material (concrete?) doesn't seem quite right either.

 

[Dan42]

I'll try to get some better pics in the morning. I'm not totally sure what you mean by 'lower the soil in that hole'? And I think the bedding you are referring to, if you are talking about below the gully's spigot, is actually part of the gully; it's just muddy giving it the concrete looking colour.

You are correct on the sealing to the joint thought, I expected to see some mortar pointing or something in there too and there is no visible material in the joint. As I understand it, this type of joint is meant to have some kind of bitumen coated rope wrapped around the end of the male end before it's inserted isn't it?

 

[ree]

Yeah, the joint is packed (careful not to push the gaskin out of the hub & into the pipe) with gaskin tarred rope before a semi dry mix of 3:1 sand & cement is pointed-in.
Its important that the joint and rope are perfectly dry before pointing up.
It must remain perfectly dry for the next 24 hrs after the fillet of S&C is installed.

If gaskin is unavailable then pack with whatever any plumbing or builder's supply has at hand. eg. fire cement rope will work.

 

[JohnD]

with the age of the house, it's very likely that the gully is cracked and broken in the ground, probably at the first bend.

Clues are that the ground around it damp, or wet if you dig a small hole. Are there any red worms, or signs that the concrete has been patched or anything has sunk? It looks to me like there are.

 

[^woody^]

If there is a leak on a clay joint then it's cracked and you need new fittings connected to a sound bit of pipe. Nothing else.

 

[Dan42]

More pics for those that asked.

Note the use of my (Pat pending) dual waste outlet diverter; I had made up the concrete to the right of the grid before finding the leaking joint, so did this to stop the two waste pipes from washing up onto it, I will be extending the wastes to avoid this in future.

 

[Dan42]

with the age of the house, it's very likely that the gully is cracked and broken in the ground, probably at the first bend.

Clues are that the ground around it damp, or wet if you dig a small hole. Are there any red worms, or signs that the concrete has been patched or anything has sunk? It looks to me like there are.

Hi John, yes, there is no dispute on the leaking joint, it's leaking at the joint between the drain pipe and the gully pot outlet and all of the things you suggested have happened.

 

[Dan42]

If there is a leak on a clay joint then it's cracked and you need new fittings connected to a sound bit of pipe. Nothing else.

Thanks for that Woody, so would the best solution be to cut the joint end off the drain pipe and fit one of those rubber collar type joints with stainless jubilee clips between it and the gully outlet then?

 

[^woody^]

Yes, but ensure that you cut the pipe back further than any crack that might be there in the collar.

It might be that once you have cut the pipe, the gap is bigger than the length of a connector, so you might need other fittings or a bit of pipe and two connectors.

A rubber band connector may have about 50mm of play, so see how you go.

 

[JohnD]

one of the delights of mending clay is that when you dig out the cracked part, you find the bit it is connected to is also cracked. So you dig out that one, and you find....

I think you will end up with a new plastic gully, and a plastic collar on the end of your pipe. It may be easier to reposition the gully to fit the pipe. The new plastic is very light so you can give it a firm platform to stand on (the wet soil will shrink and subside as it dries) and you may need to reposition the waste pipes.

Have a look at the nearby soil pipe or downpipe, I can see patched concrete so I bet you will find another crack.

 

[ree]

OP, you said that: "there's no visible material in the joint" - which indicates that thats probably where the leakage is coming from (but probe inside the hub for any rubber ring). Neither do i see any cracks in the hub, the pipe or the gulley. But you cant be certain until you test for the cause.

If you do as i suggested in my earlier post you will find the cause: remove all water from the hole, empty the gulley, & lower the soil so that the whole outlet side of the gulley can be seen, & then dry everything.

Now, slowly fill the gulley, & you will be able to see any leaking or weeping as it occurs.

FWIW:
1. your waste pipes should be combined to discharge into the gulley as one outlet.
The lower waste is entering the wall with a push-fit fitting - it should be a glued fitting, dont use push-fit in a wall. Presumably the upper waste fitting does the same?




2. There are signs in pics 3. & 4. of displaced brickwork behind the gulley.
The RWP should discharge into a gulley or it will eventually affect the lower brickwork.

3. In your final pic, what looks like a metal manhole cover can be seen - is this a m/h location or a dimpled flagstone?

4. Depending on how the drainage runs and the location of the nearest manhole it might be to your advantage to think about moving the gulley position to a more convenient/central location?

 

[^woody^]

your waste pipes should be combined to discharge into the gulley as one outlet.

A recipe for siphonage of the traps