Concrete Sub floor

[Moggaman]

Hi. I am pouring a concrete sub floor next week. The internal rising walls are left down 125mm internally to ease radon installation.

engineer has given me 2 options ...

1. Don’t get the blocklayer back to lay a block on the radon before pouring, therefore pouring the floor straight over the internal walls.. blocklayer will  then blocklayer house from this floor up. Blocks below floor are on flat and above subfloor will be on edge so blocklayer has a few mm to play with when setting out the blocks after pouring.

2. Get blocklayer back to lay a course before sub floor pour. This means continuous blocks from footing to hollowcore footing .

 

I presume option one will mean that a partial amount of wall load and hollowcore load will be transferred to the floor. 
thanks