DIY - Washbasin with Concrete Look

Perhaps some people have already implemented something similar. I am looking for a washbasin for the main bathroom in concrete look, since real concrete would not be possible due to the weight. After a longer search on the internet, I came across all kinds of providers. Basically, it would come down to a coating with so-called microcement, which is then sealed waterproof. What I have not quite figured out yet is how to design the actual construction of the washbasin. Somehow, I don’t really believe that MDF would be a good choice for this, for example.

Anbei mal ein Bild um zu zeigen was ich mir ganz grob vorstellen würde:

I would now have advised the drywall, the green ones. Because they are also used for pre-wall installations and podium enclosures in order to tile them properly afterwards.

Would be an option
But I would have to test whether the coating is hard enough for a sink.

There are so-called construction boards in different thicknesses. They are suitable for that.

Sven Backstein is a specialist - especially for such plans. He knows his stuff, has a shipping service for all kinds of concrete materials, a forum on the subject - and is really generous with his information. I have learned from him:

Concrete is what you make of it! And you can do much more with concrete than I knew before.

When it comes to "making concrete light," "foam concrete" comes to mind. A brilliant invention ...

What have you decided on now? I think the green drywall boards are suitable. Microcement can also be applied to OSB boards. Since MZ seals the underlying material waterproof, the substrate should hardly matter?