I have a paved front yard and noticed some time ago that some slabs on one side seemed to be tilting/settling. On investigation, it seems one possible cause may be the old clay gully the downpipe drains into. It has cracked on both sides more or less down to the bend at the bottom, which seems to go into a P-trap (would this be right for a c1900 property?)The haunching (correct term?) around it is also failing, so that the downpipe seems to be dribbling directly into the soil at the side of the gully.
This could have been going on for months or even years!
I'd be grateful for advice on the best way to tackle this. The radical option, I guess, is to replace the entire gully and the pipe leading to the inspection cover. Snag is, strangely, the pipe doesn't drain into my IC, but across my neighbour's property into his.
Checking under my IC, there appears to be an old capped clay pipe that must have come from that gully at one time. Certainly, the pipe on the other side of my bay window drains from the gully on that side. Don't know why its chum was capped off - maybe the electric or gas was dug through/across it? Still, it looks like I could dig out the capped one and lay a PVC one along a similar route instead. (I have an old two-pipe system, but I think the main drain under the IC carries the waste from a more recently installed toilet at the back, as well as foul water from kitchen and bath. I believe it's OK for surface water to mix with foul water in an old system - is this right?)
Disadvantages: Someone (maybe me!) has to dig a trench around 0.75m at the deepest point and 2.5m long - costly. May also need building control approval to reroute drain in this way? More cost. Also, does anyone think there may be a subsidence risk from the ground being boggy so near to the house, if I'm right about what I think has been happening? How could I allow for this and still get job done if necessary?
Alternative: Just dig out old gully and maybe old trap as well and connect new PVC fittings to old clay pipe under neighbour's wall and garden.
Advantages: simpler, cheaper, no need to dig quite so deep. May not require building control approval, as it's only a repair - is this right??
Disadvantages: Have to deal with Party Wall regulations and consult neighbour. May have to remove and replace section of wall which he's just rerendered beautifully on his side last year, never mind his newly laid granite-and-gravel porch! Also, how reliable are plastic-to-clay connections? Lastly, if my drain backs up, either he has to sort the problem or I have to get his permission to do work on his property, which could create future problems.
My first post, so very grateful for advice from tradesfolk or more experienced. I'm amazed at the knowledge of all you posters and your generosity in sharing it so widely!
I've now investigated a bit further. Dug round the gully to replace the haunching as a temporary fix. Looks like the top of the old clay trap comes up just this side of the neighbour's wall. I was surprised to see it's only about 5cm below the top of the gully itself. The water in the gully must have to rise a long way to get round that bend. From what I can see, the top of the trap is not cracked or broken. If so, there should be enough wiggle room to attach a new gully without disturbing the wall or neighbour's garden.
Questions someone might be able to help me with:
(1) Is this kind of old clay gully likely to be a separate piece from the trap, or all one moulding?
(2) If it's separate, how were they usually attached? Or to put it another way, what are my chances of detaching the broken gully from the trap without cracking the trap in the process?
(3) Am I likely to be able to fit a new PVC gully to the old clay trap somehow? (How?!) It looks like a pretty large-bore pipe.
(4) How reliable is that kind of connection? Would it be smarter to run PVC right from the gully to the inspection chamber? (I know it wouldn't be cheaper!)
Any chance of a photie? I have a feeling that you're describing a hopper and trap arrangement.
If you can get rid of the old, damaged RWP (Rain Water Pick-up), you could perhaps install a linear drain in its place, run that for the 2.5m at surface level, and then make a straightforward connection to your IC. I'd be reluctant to connect anything to the old pipe on the neighbour's property for all the reasons you mention, but, if there's no easy way of tapping in to your own drain system, it might be the only feasible option.
Once you get rid of the old RWP, fitting new components is relatively easy, and even if you had to 'start from scratch' and install anew gully and connecting pipework, it really isn't that difficult.
Tony - Many thanks for prompt reply. Yup, you're right - it's a P-trap and hopper just like the diagram on your site. Tried to email you a photo, but having trouble with the JPEG attachments that were emailed to me.
A linear drain might well do the trick. Would certainly be simpler than trenching, plus would sidestep any risk of subsidence. I'd planned to cover the entire front yard with shingle stones eventually. I guess these would be OK even if they cover the top of any grating over the linear drain, provided they're large enough not to fall through? If I choose to replace the existing paving stones instead, what do I have to put over the top of the linear drain to comply with regs?
Alternatively, I'm more hopeful now about replacing the RWP with a new hopper and trap, since I think there might be enough clearance to do this on my side of the wall - and especially since I save £130 on building controls costs on a job that probably won't cost more than £300!
Clay replacements would be most in keeping with the house, if I can find them. Haven't managed to find a supplier after a bit of Googling. Hepworth doesn't seem to do this type of fitting. Any suggestions?
From your reply, I take it fitting PVC to clay wouldn't be a problem. But what's the name of the part I'm looking for that does this job?
OK, I've looked round the site a bit more and found that I'll probably need an adjustable collar to connect a new PVC hopper or yard gully to my old clay P-bend.
But I'd still like to replace existing with a clay hopper or gully if available. Depth of current hopper (lip to inside surface of the bottom) is only about 300mm and bore at widest point (the top) is around 110mm. The downshaft of the current hopper is actually square rather than round, but no matter, since it seems to turn circular before joining the top of the P-bend.
Who might supply such things?
And if I have to cut back the existing P-bend to get rid of any cracks, would a large angle grinder do the job safely, in your experience?
Try a decent civils merchant such as CooperClarke, Burdens or UGS - they carry a MUCH wider range of drainage fittings than do the usual unhelpful suspects.
Tony - OK, I think I've identified a P-trap supplier. Once I dig the old one out, I reckon I'll need to make a gaskin joint to connect to an old socketed system.
I've read your guide to gaskin joints, but I've a couple of q's:
Does anyone still supply gaskin or how would I make some up myself?
Do I wind the gaskin round the new, plain-end P-trap then gently push into the old socket? If so, how do I keep the gaskin tightly wound in place while doing this?? Is it thin enough to wind with overlaps, like plumber's tape?
Or do I insert the plain-ended P-trap into the old socket, then push gaskin in around it?
You might be jumping the gun here a bit, your last post indicates that you haven’t dug out the pipe work yet prior to buying materials.
Vitrified Clay pipe work is like glass, the odds of removing an existing spigot end from a sand/cement jointed collar without any breakage or fracturing are remote , much easier to cut into the pipe work with a disc cutter and make a sound end for connection using a band seal coupling or flexi coupling (same thing but different).
I assume the trapped gully/p trap is taking storm water only, if so I have heard talk of pan connectors being used to make the connection into the existing pipework !
As a reputable contractor I couldn’t possibly condone such goings on, especially if building control happen to be reading this. Honest !
I wouldn't use a gaskin and mortar joint at all - I'd use an adaptor coupling, the ones with a jubilee clip at each end. Much simpler and more reliable than gaskin, and far easier to get hold of!
I had a simular problem, i had to move my drains, I installed new plastic pipes and married this to the old clay pipes.
I simply cut the clay pipe nice and square with a 9" grinder installed with a diamond blade, Then i used an adaptor that allows you to fit PVC pipe to the clay. It is a simple push fit no jubilee clips to tighten.
Once all the new drains were fitted i did a Leakage test by plugging the main pipe going into the manhole at the front of my property and was surprised that i never had 1 leak
Found it really easy to do thanks to the pages on this site...
Flowjoe - You're right. I haven't dug out the pipe yet. But I wanted to have all the bits to hand for when I do to minimize length of time I have a socking great open ditch next to my foundations!
Tony and Mick - You're right too :;): Since last post, I'd already come to conclusion I won't be able to get to the existing joint this side of my neighbour's wall and, even if I could, would probably smash it up. But I can angle-grind the existing P-trap BEFORE it passes under the wall, as you suggest.
I'll also have to cut 150-200mm off the new P-trap to make it fit - IF I get the only suitable clay one I can find, from Naylors in Bradford. But once I've got two plain ends, I can shove em together with Densleeve or adaptor, as you suggest.
One snag: I've discovered no builders' merchant anywhere near me supplies any clay drainage. Builders Centre is in process of selling off old Hepworth bits and pieces, but none suitable. Naylor warns delivery by courier means high risk of breakage, not to mention cost.
Why bother with clay at all? Well, I'd like to keep as much of the period feel of the place as possible, and the symmetry of the drains at the front. But I know plastic's easier, and I may be forced to use it anyway if Naylors can't deliver.
Tony, just out of curiousity and if you have a spare moment, I'd expect a buried jubilee clip on an adaptor to rust away eventually and release the joint. Am I being silly?
I'll let you all know how I get on. Can't tell you how grateful I am for all your help.
Trust me your house wont fall over if you expose the drain, if the foundations are that bad the drains shouldn’t be your main concern!
Its OK for a contractor to turn up with a bag full bits because he knows they will get used eventually, if you buy the wrong thing the job stops and the robbing sods at the BM charge you 15% because they had to watch you load it into your car/van when you bought it.(handling charge my arse).
Expose the drain and see what your dealing with could be a 45 degree bend on the outlet, a drop shaft or it could be surrounded in concrete, could be anything !
Vitrified clay pipe varies greatly with regard to the pipe wall size so you can at least get the outside dimension, as tony says use a band seal coupling as they can be adjusted to fit.
Hate to say this but find a travis perkins, there must be one near you because they are going for world domination. They do clay drainage and you can see whats on the market, poly pipe also do plastic gullies with a composite anti splash top that look a little better next to older properties.
Just to wrap this up, the reason the Jubilee Clip fittings on adaptor couplings don't rust away is that they are a high quality stainless steel and that, according to the sales bods at Hepworth et al, is why they seem pricey to the uninformed.
