Place new terrace slabs on old washed concrete slabs

Stop

Remove old slabs, remove split and compact with mineral concrete 3-4 cm below the bottom edge of the new slabs. Too much split under the slabs makes them wobble.

If, however, the water does not drain...

And that was exactly what I did not want to hear

: Which answer do you want now? The one that suits you, or a recommendation?

: Which answer do you want now? The one that suits you, or a recommendation?

A recommendation, of course. But that seems to be divided here as well. One says this, the other says that. And it’s logical that I would be happier if it were possible to leave the boards lying there. You don’t have to make unnecessary work for yourself since there’s still enough to do here anyway.

A recommendation, of course. But it seems to be divided here as well. One says one thing, the other another. And it's logical that I would be happier if it were possible to leave the slabs lying. You don't have to make unnecessary work for yourself since there's still plenty to do here anyway.

But we also can't look into a crystal ball. I would take the risk if I have time to spare anyway and the connection to the house is such that there is no danger from rain. However, I would expect the water to take longer to seep away.
If that is also your consideration, fortunately I'm not the villain who says it.