Soil Pipe to run through concrete slab... sleeving / shuttering etc required?

[Capable Noob]

Evening all,

 

Having built up to DPC all round, I'm now building up the floor layers within the rooms of the extension. 

 

I have a couple of soil pipes which will need to run partly through the hardcore layer and also through the concrete layer.  Any advice on how I should do this would be greatly appreciated.  I was thinking about sleeving the 110mm soil pipe inside a 160mm soil pipe (since I have a load of that) within the hardcore and concrete layers.  Or should I shutter off the route of the pipe through the hardcore & concrete.  Or should I just lay the pipes surrounded by pea shingle and backfill around it and then concrete over?  

 

The construction drawings show the layers as follows:

70mm screed

100mm insulation

25mm sand blinding

125mm concrete slab (with A252 mesh)

25mm sand blinding

150mm well compacted hardcore.

 

Also, is it ok to connect the kitchen waste into a soil pipe running from a WC using a strap boss kit (this would be under floorboards)? 

 

I hope I've described things ok.  Many thanks for any input.

[Iceverge]

70mm screed

100mm insulation

25mm sand blinding

125mm concrete slab (with A252 mesh)

 

How about. 

 

( With your SE's approval) 

 

100mm concrete slab with mesh

Slip membrane

300mm eps/200mm PIR

DPM 

 

 

3 minutes ago, Capable Noob said:

Or should I just lay the pipes surrounded by pea shingle and backfill around it and then concrete over?  

 

 

This is what the builder did on ours.