I'm working on the bathroom on the entrance floor with a basement underneath and need to install new drainage that needs to go down a bit into the concrete slab.
In the lowest part, I want to go down about 5cm into my 18cm thick slab. The reinforcement is 15cm deep.
Is this something I need to be cautious about? The weakest point must be near my new hole for the drain down to the basement. The old drain, which has been chipped away, was next to it. To fit the coupling in the hole, I need to widen the hole even more and remove 5cm to lay the drainage in.
In the image below, you can see where the old drain was, my new hole, and where I will remove 5cm of concrete. The blue is the wall down in the basement.
