Insulation foam in prefab houses - any experiences?

To achieve the certainly desired reduction of reverberation effects, it is hardly necessary to apply acoustically effective material to the entire interior surface of the recording studio.
Condensation water formation is particularly (if at all) to be feared only on the inner sides of exterior walls, top floor ceilings, sloping roofs (i.e., the heat-exchanging building envelope).
Of course, there are other problems involved:
- Flanking noise (neighbors)
- Sound intelligibility within the studio itself
- Fire protection of the building
Therefore, the urgent recommendation is:
The studio requirements should be planned separately.
From this, with near certainty, higher demands on the building manufacturer will arise. The level of requirements results, among other things, from the type of music (frequency ranges, sound power levels, airborne and/or structure-borne sound, distance to neighboring properties, window arrangements, etc.).
Subsequent "DIY fixes" are hardly effective, but significantly more expensive.

Simple method - hang heavy material on the walls, lay carpet, install double door. Also works well.

I also often recommend these "simple" solutions for sound problems. However, these are mostly cases where the building structure is already in place ... Such measures mainly only reduce reverberation (but thus also, to a small extent, the sound level). Strongly impulsive as well as low-frequency noise disturbances are hardly adequately addressed by this. In particular, structure-borne sound problems unfortunately remain (almost) completely. The already given advice to install double doors naturally belongs in the planning concept to avoid later retrofitting.