ᐅ Core drilling without a structural engineer's calculation

Hello,... quick question.

I want to install a new level shower drain and had to drill through the floor slab (built in 1978, 18 cm (7 inches) reinforced concrete + 7 cm (3 inches) screed) towards the basement. The old drain opening cannot be used.

Is it safe to drill such a relatively "small hole" without compromising structural stability?

Why 62 mm (2.4 inches)?
I would borrow the core drill, and the rental company said the smallest drill bit they have is 62 mm (2.4 inches), although a 50 mm (2 inches) hole would actually be sufficient for me.

Thanks in advance for your answers.

I am not a structural engineer! If this hole would cause the ceiling to collapse, something else must have gone wrong beforehand.

If no beams are installed, you can start right away. If there are beams, I would try to locate them and then avoid them.

You can go all out with the 62cm (24 inches). The ceiling won’t mind.

If the hole is going to be 62cm (24 inches) in size, it starts to get interesting to ask these kinds of questions.. 😉

50mm (2 inches) is also possible with a proper SDS-Max drill bit if available

Hello, thank you very much for the responses.

Good luck