Hi, - more problems!
The main drain pipe from our house seems to have broken in 4 places in the field adjacent our house. Some large vehicle must have driven over it at some stage.
If I was to replace this section of pipe, is there any regulation as to how deep it should be buried? I guess to maintain the drop this will involve building up the ground around it.
The pipe is 9 inch internal diameter, made of clay(?) and goes into a mains sewer.
TIA Colin
There is if you were replacing the whole lot but as a repair you can replace like for like.
But as it's been broken once, I'd look at adding some protection.
Replacing like-for-like sounds like a good idea.
Any idea what guideline depth I ought to be aiming for?
Cheers, Colin
You may not have any choice! The start-point - where it leaves your property and the endpoint - where it joins the public sewer - are pre-defined. Unless there is a very large vertical drop relative to the horizontal distance - which would allow you to go vertically down from the start point before starting the horizontal-ish run - you'll by restricted to simply laying it in a way which gives a constant gradient from start point to end point.
The easiest way to proceed is to carefully cut the clay pipe near each end with an angle grinder. Then remove the clay pipe between the cuts and replace it with plastic. At each end, join plastic to clay with flexible rubber couplings, held on with jubilee clips, designed for the purpose. The new pipe needs to be bedded in, and surrounded by, several inches of pea gravel. If vehicles are going to go over it, concrete slabs over the pea gravel but under the topsoil would be a good idea to spread the load.
The same depth it is now, if you're replacing like for like, but make some sort of protection which is going to take more weight. Encasing the pipe in a concrete sheath will make it slightly more robust for heavy vehicle traffic.
Dig out the old pipe, exposing the whole thing all around it for about a 500 mm or so. Replace the pipe and make good. Pour in a couple of tonnes of pre-mix concrete all around it to make up the 500 mm below and above the pipe.
Make sure it left exposed for a couple of days, to allow the wet mix to cure properly, then back fill it. Should give the pipe a lot more strength for vehicle traffic passing over it. And it's not that expensive to buy a load of pre-mix concrete.
On Sat, 18 Jun 2005 07:13:51 +0100, a particular chimpanzee named "Colin" randomly hit the keyboard and produced:
The same depth as the bits of pipe you're replacing.
You say it's a 225mm (9") pipe from _your_ house? Does this just serve your house, because 225mm seems very large. A single house would normally only need a 100mm diameter pipe; most housing estates don't need anything larger than 150mm.
If it is excessively large, and there's no good reason for it (it's not also serving a culvert, for example), you could line it.
In article , Hugo Nebula writes
Don't suppose they would, unless the network traffic was too large at any time for the "pip". Now I suppose someone does some calc's of an outbreak of the colly wobbles and the probability of system overload;)....
You may have to keep the pipe at the same depth and fall as at present to maintain its operation unless you have a dispensation from the laws of gravity
It sounds a bloody big pipe - is it shared between a number of properties or have you a specific need for that size? In any case it may need protection from heavy loads by other means if the depth is fixed. Concrete makes a good protector as long as it is strong enough
Good point. Q to the OP - is this also a flood culvert ? If it is you may find the EA own it and will repair it for you.
Yes, definitely 9 inch internal diameter. It only serves our house (sewage and rainwater).
Someone suggested that maybe possible to place a smaller diameter pipe through the middle. Problem is, the run is well over 100m. I guess that it would not be wise to go from 9 inch to 4 inch as it may cause things to back up a bit(?)
Colin
On Sun, 19 Jun 2005 09:00:55 +0100, a particular chimpanzee named "Colin" randomly hit the keyboard and produced:
Provided it's laid to a fall, it shouldn't do. You might want a couple of chambers along the run; the max recommended length between inspection chambers is 45m. As I said before, you could consider lining the pipe.
Do you know whether the pipe is completely smashed in places? What symptoms are you suffering?
In some cases, pipes can be lined - but it's not a DIY job. A plastic lining - like a very long sock turned inside out and inpregnated with resin - is propelled through the pipe using compressed air, and then trimmed at the end once in situ. Once the resin goes off, it forms a rigid liner which bridges any small cracks and mis-alignments in the pipes. Then internal diameter of the pipe is reduced by only a very small amount. The beauty is that it can be installed with with minimum of excavation. It's usually necessary to send a remote controlled camera down the pipe first, to identify any major breakages. These have to be excavated, but the remainder can simply be lined.
This technique is frequently used by water companies. A private sewer which passes under my garden - altough it doesn't serve my property! - has been lined in this way.
What a fantastic solution.
I haven't excavated the pipe fully, but I suspect it is totally smashed in at least two places as I have uncovered some large chunks of pipe.
I may pursue the insurance option. I am starting to think that the problem is one of those that get worse and worse the deeper you get into it.
Colin
If you are going to burry it in concrete (60 quid a cube round my way, assuming you buy 6 cubes), you might be better to consider replacing the whole pipe, an excavator can do 100m a day (a long day) for 15 quid an hour including driver round my way.
Modern plastic pipe will have a bit more give than the old clay ones, but price the pipe up first. There are special stronger pipes for putting under roads, which will mean no concrete.
I replaced my whole water pipe, 200m, becase it leaked twice, and I wanted to not have it leak again.
To save attaching to the main sewer, you attach your new pipe a foot or two back from the main sewer.
Rick
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