ᐅ Complete wood flooring for a living area in the attic?

Hello,

Is the following floor structure for the first floor (= inhabited attic) feasible:

New build:

Joists
On top of that, a 20mm (0.8 inch) wood boarding for visual effect (the entire ground floor ceiling will therefore remain visible)
On top of that, 15mm (0.6 inch) OSB
On top of that, timber battens (100mm x 100mm (4 inches x 4 inches)) spaced 400mm (16 inches) apart as the installation cavity
On top of that, 22mm (0.9 inch) OSB

I assume insulation with a vapor barrier and so on still needs to be installed in the installation cavity. I am informed enough about what to do there.

The area is intended to be lived in (so bedroom, bathroom with shower and bathtub). Except for the bathroom, carpet will be installed everywhere. Tiles in the bathroom.

Thanks and best regards

So, this will be a standard first floor. It is located directly under the roof. There will be a normal staircase leading up, with a typical ceiling height (70cm (28 inches) knee wall, 35° roof pitch). There are also windows: the bedroom has one, the bathroom has two, and the dressing room has one. There are no emergency exits except for the staircase.

Windows can also serve as emergency escape windows if they are of appropriate size:

Openings in windows that are used as escape routes must have a clear opening of at least 0.90 m x 1.20 m (35 inches x 47 inches) and be installed no higher than 1.20 m (47 inches) above the finished floor level.

I am not an expert, but I wonder if a vapor barrier might be incorrect.
From what I have read, only the exterior walls and roof should have a vapor barrier.
Otherwise, perhaps impact sound insulation? For the bathroom, definitely flexible tile adhesive.
For safety, out of ignorance, I would seal the substrate with an appropriate compound or membrane, as is done with walk-in showers... but this is just a thought from me, not professional knowledge! 🙄

It is also possible that no vapor barrier is needed. I’m not entirely sure about that. The exterior walls will be a double-layered log wall with cork insulation in between. There is no vapor barrier included.

But since everything is really made of wood, I want to avoid moisture and mold formation at all costs :-)