Thickness of installation plates for attic?

Dear forum members,

We are getting a prefabricated house at the end of the year. The floor of the unfinished attic will still be open. That means the beam structure of the ceiling is visible and not yet walkable. We would like to make the attic walkable by installing a cross battens and laying floor panels on top, so that some things can be stored there. I hope someone here is familiar with this and can tell me at what distance the battens should be placed and what thickness the floor panels need to be for it to be safely walkable.

Thank you very much in advance for all the answers.

It is rumored that tongue and groove is better suited because there is no vapor barrier

Would take 32-35mm OSB as covering with tongue and groove. Battens can then be omitted.

I would use 32-35mm OSB as a covering with tongue and groove. Battens can then be omitted.

And then that stuff will mold away on you. Either there has to be ventilation under the OSB board so that the moisture can escape, or you use tongue and groove boards.

Either there must be ventilation under the OSB board so that moisture can escape or you use tongue and groove boards.

Can I be sure that nothing will mold with tongue and groove boards? I was told that I should preferably put the boards up first and wait until I need the space, and only then lay the wood (or OSB boards). The insulation and vapor barrier will be beneath these floorboards or boards in our case.

The problem is that the OSB boards themselves represent a vapor barrier, i.e. possibly rising moisture cannot pass through but remains underneath. If the moisture also cannot circulate sideways, it stays in the insulation and mold begins to form. Rauspund has the advantage that the wood does not represent a vapor barrier, but moisture can pass through. We played it safe and installed a counter batten and laid Rauspund.