Construction of wooden beam ceiling single-family house 2-story with gable roof.

Hello,

for our two-story single-family house, we celebrated the topping-out ceremony 10 days ago.

However, I am concerned about a few things regarding the construction of the wooden beam ceiling:

-The carpenter directly laid a walkable floor on the beams over the entire area. These are OSB 3 boards.
-The boards are directly attached to the beams. No battens in between.

A full insulation between the beams is planned later during the interior construction along with a vapor barrier, battens, and plasterboard. The attic itself will not be heated. The roof slopes will not be insulated.

I am worried that due to the lack of ventilation and the diffusion-tight OSB boards directly on top of the insulation, condensation and mold may develop. Is this construction faulty, does it comply with building regulations, or am I overreacting with my concerns, what do you think?

-The boards are attached directly to the beams. No battens in between. [...] I am concerned that due to the missing ventilation [...] Is this construction faulty, does it comply with building regulations,

What do you want with battens at this point? - I would say that the "missing" ventilation here is precisely what complies with the regulations

I would not want it like that: The insulation above should only be covered with a significantly lower Sd value than below.

I would have also chosen tongue and groove boards. The concerns about moisture on the OSB panels are not entirely unfounded.

Is the problem in the material of OSB boards or in the lack of ventilation?

What do you want with a battens at this point? - I would say that here precisely the "missing" ventilation complies with the rules

Why do you hold this opinion? Can you please explain further?