Using prefab house walls for acoustic purposes

Part 2: Integrating the inherent insulation with the incorporation of additional rockwool layers

Ves2 Prefab Insulation 2

Now that we have preliminary floor plans, which are unlikely to change, it’s time to assess how much sound absorption I can incorporate into the room without compromising significant space. I will be applying the same principle used in my first room. However, this time, I intend to follow the specifications outlined in the MyRoomDesign white paper to the letter. Although more detailed information will be provided later, for a preliminary overview, each wall will incorporate 60 cm of absorption, concealed by air transparent diffusers.

The design involves vertical slats with open spaces between them, allowing for air/sound circulation. Behind these slats, there is a layer of rockwool for sound absorption.

The shaded region encompassing the room labeled as number 5 indicates the presence of built-in insulation. For a closer look at the wall layers, refer to the image below. The light blue area marked with “X” signifies the additional insulation to be incorporated.

Using the sidewall insulation

The house walls are constructed with various layers, including thermal insulation commonly used for acoustic purposes. The idea was to use this insulation and save some space inside the room. To achieve this, the manufacturer agreed to keep the walls partially unfinished by excluding layers 7 and 8. Ideally, perforating the outer layer of insulation (4) would have allowed the full utilization of the 30 cm thickness. Unfortunately, this option was not viable.

  • 1 Final facade layer (2 mm)
  • 2 Reinforced mortar and mesh (5 mm)
  • 3 Facade insulation, rockwoll (140 mm)
  • 4 OSB board (15 mm)
  • 5 Wooden structure + thermal/acoustic insulation, Knauf NaturBoard FIT rockwoll, (160 mm)
  • 6 Vapor barrier (0.2 mm)
  • 7 OSB board (15 mm)
  • 8 Gypsum fiberboard (10 mm)


Using the ceiling insulation

The entire house features a substantial layer of rockwool insulation within the ceiling. An appealing choice available in the manufacturer’s options list is a perforated ceiling (PDS-Rigitone-8-15-20-SUPER), allowing thorough sound absorption. This would be useful because the ceiling height is 250 cm, leaving limited space for additional acoustic treatment.

  • 4 Wooden structure + thermal/acoustic insulation, Knauf NaturBoard FIT rockwoll, (500 mm)
  • 5 Vapor barrier
  • 7 Perforated drywall