Rerouting A Sewer

[thomp1983]

So you'd suggest go with the original blue option, get the ic built at point 4 and the pipes to a from it in place then worry about the connections to the existing ic's?

But how would you be making the connections into the existing parts? Yes I could get into ic 2 and do the work required albeit it would be a grim mornings work but is there another way around it?

 

[Hugh Jaleak]

So you'd suggest go with the original blue option, get the ic built at point 4 and the pipes to a from it in place then worry about the connections to the existing ic's?

Yes, that is what I'd do. Lay your diversion route, then connect up as the last job. Both connections would then be fairly straightforward, downstream look to be a straight through run, and upstream a 150mm straight through with a 100mm lateral coming in at 90° The old sewer can then be abandoned and you're free to build.

But how would you be making the connections into the existing parts? Yes I could get into ic 2 and do the work required albeit it would be a grim mornings work but is there another way around it?

I would be very wary of working inside an existing chamber of that size, there is a risk, (albeit probably small, but none the less a risk), of exposure to sewer gases, and it doesn't take a very high level of Hydrogen Sulfide to cause a fatality. If ST will accept a plastic chamber base, there is your answer. Start knocking the brickwork down as you go, once at a suitable point, bung off the inlets. Remove remainder of chamber, set new plastic base in a concrete base of the required size for the new chamber. Couple onto the existing connections and new outlet pipework, then pull bungs to release backed up effluent.

 

[thomp1983]

So to make the connections I basically demolish the current ic 2 to a safe open work area either fit a plastic tray or make the new clay connections then rebuild the ic back upto where it needs to be and call it done?

 

[Hugh Jaleak]

So to make the connections I basically demolish the current ic 2 to a safe open work area either fit a plastic tray or make the new clay connections then rebuild the ic back upto where it needs to be and call it done?

Yes. I really would not advise trying to bodge something out of the existing chamber. Any proposal will need running past ST beforehand anyway, it is technically their sewer so any diversion works will have to be to their requirements.

 

[bernardgreen]

You will also have to make arrangements to deal with the sewage coming from your neighbours while you are re-routing the sewers.

 

[thomp1983]

Spoke to my builder today and he suggests digging up the original sewer between 1 and 2, replacing it in plastic then bridging it with lintels for the foundations, he says he's done it a few times and there's never been issues and it's time efficient as half the soil removed can be disposed of as it with be part of the over site that would be removed anyway

 

[thomp1983]

Well it's been a busy week, builder started Monday, we spent a couple of days clearing the site then Wednesday morning began digging down to the existing sewer. We started at IC 2 and found the clay pipe at 1350mm, we then worked backwards following the clay pipe, unfortunately hit the water supply to the house as it ran the same route as the drain just higher in the ground and turned at the corner of the house to below the kitchen sink.

Digging was hard going, the ground seems to have a lot of concrete, rock and debris in it, it took about 6 hours to dig half the trench, at roughly half way (about 1.6m) we started to get some cave in on the trench so made up some rough and ready supports. Thursday morning saw the rest of the trench dug, and then we set about removing the old clay pipework and relaying with plastic, typically the clay pipe was in very good condition with just some minor root growth inside it and probably would of lasted another 40 years.

Building inspector came today and signed the work off so several tonnes of pea gravel have been distributed over the new pipe and the trench mostly filled back in apart from the areas the sewer will need bridging with lintels.

Next week we can actually start digging the foundations and getting back on track, this sewer has been a distraction and I'm happy it's squared away and hopefully should produce no further issues.

Thanks for all the advice,
Chris