Thickness of blocking board

[Shira]

Hi all!
I want to build my own blocking board.
If any of you own a good blocking board, can you pleaes tell me how thick I should make it?

Thanks!

[hyperactive]

Hi!
I do not call myself and expert. But I bought 2 sheets of styrofoam, 2cm thick, white. And if I need something wider, I put them next to eachother.
You just need to store them somewhere easy because they would be breaking if I tossed them in the corner.

[Shira]

Eventually I bought some kind of a baby mattress, which looks like a puzzle and used that: it's perfect! not very expensive I think (10$) and it's easy to put away after use...