Construction plastic in the ceiling?

[Tååmten]

Hello, I've torn down the ceiling in the hallway up to the sparse paneling to install a new ceiling. It had wood paneling, dark and gloomy, and behind that were fiberboards, from the '60s, followed by the sparse paneling.
It seems there's some kind of black paper on top of the sparse paneling, under the insulation up in the cold attic.

I planned to put construction plastic between the new ceiling and the sparse paneling but could that cause problems?
How permeable is the black paper on top?
Do I risk trapping moisture in the sparse paneling between the paper and plastic?
The hallway is located outside the bathroom where it gets humid despite the new fan, allowing moisture to seep into the hallway.

The same question is likely to arise when the bedrooms and kitchen are renovated later on...

 

[useless]

make a few cuts in the pappen and it won't be airtight anymore.

 

[Isakare]

No plastic in older houses, let it be as it is.

 

[Tååmten]

Thanks for the response.
Just one thought.
There is growth on the raw board above the bedroom, which usually means that humid air has seeped up.
Now the conservatory is outside the bedroom and the conservatory fence extends under the eaves.
I guess the previous owners have had the door or window between the bedroom and the conservatory open so that warm, humid air traveled from the bedroom to the conservatory and then seeped up through the transition between the roofs.
But it could also be that the bedroom ceiling is not airtight...
Are there risks with placing building plastic under the sparse panel even with windproofing above?
A bit of belt and braces...
Installing building plastic now is easier than addressing leakage later. But not if it increases other risks.

 

[goosen]

Thanks for the response.
Just a thought.
There's growth on the rough sheathing above the bedroom, which usually means that humid air has seeped up.
Now the conservatory is outside the bedroom and the conservatory fence goes under the eaves.
I guess the previous owner had the door or window between the bedroom and the conservatory open so warm humid air went from the bedroom to the conservatory and then seeped up through the transition between the roofs.
But it could also be that the bedroom ceiling is not tight...
Are there risks of installing construction plastic under the slatted panel even with windpaper above?
A bit of suspenders and belt...
Installing construction plastic now is certainly easier than addressing seepage later. But not if it increases other risks.

How did you do it? Did a similar renovation and put plastic on the ceiling before putting up new slats.
I have been up in the attic and cut holes in the old diffusion paper. Previous paper was damaged in many places.
I was told that there shouldn't be a problem with moisture on the warm side anyway. Previously had problems with black mold in the attic due to leakage of humid air from inside up to the attic.