Beadboard on renovation gypsum

[redtroll]

I was thinking of installing beadboard on the walls in my old cottage. Today it's tretex with wallpaper. The walls are even, so nothing is needed to smooth them out. My question is whether one should still install renovation gypsum on the wall under the beadboard?

 

[Jonatan79]

No, unnecessary. Is there wood behind the tretex to fasten the paneling into?

 

[redtroll]

No, unnecessary. Is there wood behind the three-ply to attach the tongue and groove paneling to?

Yes, there are planks behind, so it shouldn't be a problem. I was mostly curious if the plaster had any other function than smoothing out irregularities.