What is walnut like to work with, and how does it function in bathrooms?

[Yrrol]

I have a box in the bathroom that I think could become nice if it gets a top made of walnut.
And I have an overhead box for spotlights, which I think could look nice with a walnut trim around its edge.

But.

1.
How is walnut as a type of wood?
* Is it resistant to moisture?
* Can you varnish walnut so you don't have to maintain it with oil?
* Can you varnish it with 10 layers so it looks like plastic similar to the newer Volvo car panels that are said to be real wood?

2.
If I now would need to break the board off later, I'm thinking about the next problem - damaging the moisture barrier underneath. Are there solutions to this so the moisture barrier isn't damaged?


Left image = walnut furniture in a white bathroom.
Right = my bathroom today with its box.
Middle = quick collage with the tiles I bought and the consideration of the walnut board placement.

 

[Helioz]

1. Walnut is moisture-resistant and works well in bathrooms. Wood in a bathroom environment should definitely be lacquered not only because of the moisture but also because it is the room in the house where the most and strongest chemicals are used and spilled. The walnut should be lacquered with a polyurethane varnish and nothing else. One-component is fine with 4-6 layers. Floor lacquer or, preferably, boat lacquer should be used.

2. Regarding the installation, you might consider drilling in a few very strong neodymium magnets on the underside of the board that align with the screws securing the wet room board. This should be sufficient to keep the board in place and will not damage the waterproofing. Perhaps one of these:
http://www.clasohlson.com/se/Neodym-magnet/Pr310564000

 

[Yrrol]

What do you think about the construction technique? I'm considering placing a tile board on top of the moisture barrier, then using silicone to attach the wooden board on top of the tile board. The day the board needs to be removed, you can use piano wire or something similar to cut it off without much force, reducing the risk to the moisture barrier.

If it were only a tile board, one would want the lid to cover the sideboards to avoid seams, but since the intention is to have a wooden board on top later, the final result will look better if I pull the sides all the way up with a smaller tile lid.