concrete floor construction

[nottsrob184]

Hello again all.
As mentioned before i am self building a single storey extension to form a new kitchen / dining room.
I have just completed the 4 courses of eng' bricks to bring me up to the existing house dpc.
Next job i quess is to dig out for the concrete floor base.
So here goes....
1. How deep do i have to dig out?
2. What are the floor construction layers (hard core 100mm etc) that will satisfy building inspector?
3. I need to add a drain to a manhole from a planned kitchen unit island....can this go in the concrete or should it run under the lowest level of the layers and come thru' the concrete vertically?.
Sorry so many questions.

Thanks so much for any advise.

 

[noseall]

1. How deep do i have to dig out?

A standard floor detail consists of,

100mm (min) compacted hard core (usually 30mm-dust mot).

25mm-50mm sand blinding (also compacted).

1200g dpm layer.

80mm-125mm insulation layer depending upon spec' i.e. celotex/kingspan, jablite etc.

Polythene protective barrier layer depending upon insulation.

100mm (min) concrete slab.

75mm screed.

Note: the insulation can be positioned above the slab and directly beneath the screed if necessary.