Posted: Fri Dec 22, 2017 7:51 pm
Hello, all. Like the great many I have found this site both reassuring and informative when approaching the unfamiliar world of underground drainage. I would be grateful for any advice on my current issue:
A 6" saltglaze public sewer runs across my back garden, at a distance of 3m from my rear wall - this is exactly where the foundations of my new extension need to go. There is a brick built inspection chamber roughly in the centre of the run, with an invert depth of roughly 1.8m. The dilly of a pickle that this presents is that the sewer pipe deviates by around 7-8 degrees towards the house, in the chamber, and then heads straight to the next chamber in my neighbour's garden, downstream.
Because there are other existing buildings in the way, my preferred solution is to use a 45 degree bend (with rodding eye access, to bring the sewer 1m closer to the house (Thames Water seemed accepting of the idea, as it would be no different to a build over as if the sewer were already only 2m from the house) and then have a plastic inspection chamber to change the direction back so it is parallel to the rear wall. There would then be a straight run under the entire width of the extension.
The problem is, as all the bends only come in 15, 45, and 90 degrees, how can I accommodate the 7-8 degrees mismatch of the two pipes once they are within touching distance - to allow me to use a second plastic IC; 450mm with reducer ring - to reconnect everything, and also accomodate the new foul from the extension.. The only solution I can come up with is to build a brick or concrete chamber (the smaller the better, so an IC, rather than a manhole), but I'm hoping there is an easier option.
All help gratefully received, as I'd like to present a good first option to Thames Water to start.
Kind regards, and Merry Christmas.
A 6" saltglaze public sewer runs across my back garden, at a distance of 3m from my rear wall - this is exactly where the foundations of my new extension need to go. There is a brick built inspection chamber roughly in the centre of the run, with an invert depth of roughly 1.8m. The dilly of a pickle that this presents is that the sewer pipe deviates by around 7-8 degrees towards the house, in the chamber, and then heads straight to the next chamber in my neighbour's garden, downstream.
Because there are other existing buildings in the way, my preferred solution is to use a 45 degree bend (with rodding eye access, to bring the sewer 1m closer to the house (Thames Water seemed accepting of the idea, as it would be no different to a build over as if the sewer were already only 2m from the house) and then have a plastic inspection chamber to change the direction back so it is parallel to the rear wall. There would then be a straight run under the entire width of the extension.
The problem is, as all the bends only come in 15, 45, and 90 degrees, how can I accommodate the 7-8 degrees mismatch of the two pipes once they are within touching distance - to allow me to use a second plastic IC; 450mm with reducer ring - to reconnect everything, and also accomodate the new foul from the extension.. The only solution I can come up with is to build a brick or concrete chamber (the smaller the better, so an IC, rather than a manhole), but I'm hoping there is an easier option.
All help gratefully received, as I'd like to present a good first option to Thames Water to start.
Kind regards, and Merry Christmas.
Also you can read building regs part h about depths of founds with drainage because could need concrete surround.