Adding drains to existing cesspit - Drainage

[cliff1010]

Hi can someone help, I am in the process of converting a stable block into an annexe. I am now looking at drains, the option was to get someone in to do this but I have run out of money so will attempt myself. I can borrow a digger so not all back breaking work.

I am confused everything i read states drains at specific height but my cesspit pipes are very close to the surface (aprox 10"). Building control dont seem to worried and have given me advice to start from the inspection chamber i will be connecting to and work back. ( that is all the advice they will give me) I understand the fall 1:80 as a WC will be attached. my problem the drains will be shallow and go under a drive how do i do this . e.g. what depth is acceptable and as it's so close to surface do i have to cement over these ? I was also told as i am going under a drive i need flexible connections, again confused if i use flexible connections and then cement how does that work. Can someone offer advice or point me in the direction of a good book. I know about the pdf document H but didnt find that much help.
Thanks cliff

[cliff1010]

could you also give me some advice on how much it would cost run from annexe to first bend / inspection chamber is approx 7 m the about 4 m to connect.

I am in canterbury in kent.

[seanandruby]

At the depth your pipes are they will need to be encased in concrete. The flexible joint joint is a piece of fibre board placed upright at each joint the full width and depth of your concrete. Go to the drainage index for more information. And don't panic it's nothing unusual. Also read concrete mixes.

[cliff1010]

Thanks Sean,
I take it as the pipes are to be encased in concrete I need somehow to hold them up and not bed on shingle. is it acceptable to just prop them on bricks while I pour the concrete ?

Cliff

[seanandruby]

Yes as long as you take the bricks out as you concrete. But you can pull a string line and lay your bedding first, so don't need bricks, just dip down whatever your pipe size is from string line to top of bedding. Also don't have the concrete to wet or they will float.

[cliff1010]

Sorry Sean,
I am being a bit dim I thought as it's encased in concrete it would not have bedding. Good point about the wet concrete noted.

Cliff

[rxbren]

Concrete is the bedding
personally id lay the concrete first then lay the pipe that way it will be easier to not have any voids under the pipe
if you suspend the pipe there is a chance it will move as you try to pack concrete under it

[cliff1010]

makes sense thanks for that