The Brew Cabin

Posted: **Sat May 26, 2007 5:34 pm**

Hi, I am planning to build an extension at the rear of my property for a kitchen and am undertaking the groundworkâ€™s myself. Building regulations have been approved for the build. The local water company have insisted that we disconnect existing connections from the sewer (100mm) which will run underneath the planned extension, and take them to a new private manhole outside the extension footprint.

So to be granted approval to work by the local water company I need to send them a method statement and risk assessment. My plan is...

â€¢ Cut the existing 100mm vitrified clay pipe and fit 90Â° bends
â€¢ From the bend run 1600 lengths which will leave the â€œnewâ€� section & IC 1000mm from the kitchen wall.
â€¢ Install the inspection chamber along this run.
â€¢ Connect the WWD to the inspection chamber, and then either run a length (3500mm) from the RWD to the chamber or connect the RWD to an oblique joint near the drain.

Questionsâ€¦

â€¢ Firstly are there any flaws / easier ways to do this??
â€¢ I am concerned that four 90Â°â€™s are too many changes of direction for a sewer pipe??
â€¢ Where the pipe passes through the trench fill foundations it need bridging. Whatâ€™s the easiest way to provide the 50mm clearance, a wooden "box" or are there specially designed products. Iâ€™ve heard of â€œRocker Jointsâ€� around. Is this anything to do with this??
â€¢ Can the RWD be attached to an oblique junction near the drain to save a 3500 run, or will it have to be attached to the chamber.

Thanks

Mason79

Posted: **Sat May 26, 2007 5:42 pm**

any place a sewer run changes direction you normally need an IC,they will NOT let you use 90's on a foul run,15 degree easy bends is the preferred method for a slight change as they are roddable ,but by the sounds of it you need 3 IC's
pain in the neck but such is life
cheers LLL

Posted: **Sat May 26, 2007 7:08 pm**

you will need inspection chambers , or, manholes for changes of direction. a larger diameter pipe, a box out, or, sand bags to get you through the concrete to give you all round clearance. if its through brickwork a small lintel will do. a "rocker pipe" is a piece about 600 ml long, you will need one each side of a wall 150ml away from the face attached to a length of pipe through the wall, also one outside a manhole attached to a stub pipe that is also 150ml away from face of wall. Isn't there another route you can take to lesson the bends? good luck.

Posted: **Sat May 26, 2007 7:19 pm**

LLL is right, if you are not careful you will have a garden full of I.Cs

Try the osma or hepworth drainage sites, i`m sure they do a free design service if you can supply drawings, that way you know it will be up to Part H standards.

You are working with pre-determined falls so be careful if you are putting twice as much drainage in or you will end up with a level system or worse one with backfall, might be worth getting a specialist to take a look.

Posted: **Sun May 27, 2007 1:42 pm**

they used too let us lintel over pipes but for some reason the water companies don't like you going over them now especially if there are other houses connected to the run
summat about access
LLL

Posted: **Sun May 27, 2007 4:04 pm**

We used a small concrete lintel over a foul run we installed in a new build last winter, all seemed ok with the powers that be.

Posted: **Sun May 27, 2007 5:46 pm**

On a intense programme job the "new faster" way of doing drainage is to be chased along with ....chippies, steel fixers and concrete up your bottle. the manholes are cast on site with the chambers in situ. you have your inlets, outlets and laterals coming off them. they are anything from 100ml up to 300. i have to attach diminishing pipes ( reducers to you ) to some. depending on availability ( if they are cast quick enough ) i have to either put the manholes in and pipe off them, or, put the pipe runs in first whilst we wait for a manhole. as you can imagine the levels have to be bang on, ha ha ha. the point is , i then have to connect up pipes from different directions. to achieve this i have to put some very intricate bends. i am sure all rules are broken. but my job is to get it all connected fast. i will post some photies ltr.

Posted: **Wed May 30, 2007 9:41 pm**

ok breaking rules until it comes time for adoption then you wish you had spent that little bit extra time on the pipe laying in the first place

The Brew Cabin

Drainage around extension footprint - Install ic & re-route sewage pipe