Drainage - Replacement

[davidm]

Hello all.
I have excavated to expose my existing drainage, as it is damaged in one part, and the inspection chamber needs attention (see previous post). The system is an old untidy socketed clay system that seems to change direction and height with every connection! I've decided that it would be (probably) straightforward to replace the whole system from gulley (rainwater and kitchen sink) and soil stack connection to inspection chamber in plastic. I'd like the simplest and neatest system possible. If I can get away with a mini access chamber or even no chamber then even better. My drain is at the 'head' if you like of a run that goes through at least 2 neighbours' gardens. A couple of questions:
1) Are there any obligations with me being at the 'head' of the run with regards to access/rodding points?
2) I'm confused about the minimum depth above plastic (no vehicular traffic) is it 600mm, or can I, as per Brett Martin guide, be ok with 300mm plus paving slab above the bedding for additional protection from Garden implements etc.?

Many thanks for reading.

[seanandruby]

Is it a combined foul/surface water system? Try Osma drain. Your invert will bé governed by the next I C or Manhole along for your fall, depth etc. You'll need a trapped gully for the kitchen waste, then an I C, also a stepped clay to plastic coupler.Run your existing pipes into the I C, lay new pipe from your I C as far as you intend. If you can't achieve min' depth then concrete surround or, as you say; bridge with a flagstone to avoid deflection of the pipe. Where are you located ?

[davidm]

Thanks seanandruby. Yes, it's a combined system (I've got to check exactly where the soil pipe connection is). I guess as far as fall and depth is concerned, I'm constrained by the position of the pipe going to next door (currently this is a short length as the IC is only about 500mm from the boundary wall,and it seems to go under their extension), and also the (fixed) height of where the gully grid can be outside the back door. Also constrained by the max/min fall of 1 in 40 for soil? Should be IC and trapped gully be bedded on a slab or concrete? I'm in Leicester by the way.