📊 Extreme Density (Mass)
A standard white board weighs about 8-9 kg per square metre. An acoustic board weighs 12 to 15+ kg per square metre! The gypsum inside is incredibly compressed.
Acoustic Plasterboards (Acoustic Drywalls): Why They Are Heavier, Denser and How They Work
In the war against noise, we always remember the Mass Law: Weight stops sound. Now that we have erected our metal stud frame and filled it with the "sponge" (rock wool), we need a heavy, solid shield to seal the wall.
The industry, knowing that plain cardboard and sparse gypsum are not enough, created Acoustic Plasterboards (you will usually find them in shops with blue, purple or special markings).
What Hides Inside the Gypsum? (The Difference)
Externally, they look just like standard plasterboards. Same thickness (usually 12.5 mm). The enormous difference, however, lies in their core.
🔬 Fibre Reinforcement
To prevent it from crumbling under its own weight and to make it more flexible (so it better absorbs vibrations), the core is often reinforced with glass fibres or other special mineral additives.
🔥 Damping (Elasticity)
The top-tier (and pricier) acoustic plasterboards worldwide have a property called "core elasticity". When the sound wave strikes them, the slab "flexes" microscopically, converting acoustic energy into heat instead of transmitting it to the frame.
Why Do We ALWAYS Install Two Layers?
A common question is: "Since acoustic plasterboard is so heavy, why not install just one to save money?"
The answer is twofold:
- Doubled Mass: With two layers, we reach 25-30 kg per square metre (adding precious dB to the sound reduction).
- The Staggered Joints Rule: Sound passes through gaps. When we install two layers, the craftsman ensures the seam of the first board is covered by the "blind" centre of the second board. This seals the system perfectly.
Is the Price Difference Worth It?
A standard white plasterboard costs about €2.50 – €3.50 per square metre. A good acoustic board costs €5 to €8 per square metre.
It looks like double the price, but consider this: on a 10 m² wall, the extra material cost is only €50-€80. It is criminal to pay for labour, metal studs and rock wool, and then skimp on €80 for the very "shield" of the system!
The Experiment in Our Model (Cladding the Stud Wall)
In our room (4×4) we are ready to "close" the metal stud frame on the wall.
❌ Scenario A (The Cheap Option)
We ask the builder to install double standard white plasterboard to save €100. The boards go up, get filled and painted. The wall weighs 17 kg/m². When the neighbour turns his TV up, mid-frequencies (voices) are blocked, but the bass manages to vibrate the light gypsum. We hear an annoying buzz.
✅ Scenario B (The Acoustic Armouring)
We buy double acoustic (blue) plasterboard. The builder grumbles about carrying them because the wall now weighs almost 30 kg/m²! We close the wall. The enormous mass of the new boards cannot possibly vibrate from the TV bass. The wall is now a genuine "rock" and the room is utterly silent.
The Final Conclusion: Acoustic plasterboard is not a luxury - it is a prerequisite. It is the final "goalkeeper" in the Mass-Spring-Mass system. Without its special weight, sound will find a way to make your wall sing.
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Wall Soundproofing: Anatomy of the Perfect Stud Wall Mass Loaded Vinyl (MLV): The Ultimate Soundproofing Weapon The Mass Law in Sound Insulation: Why Concrete Alone Is Not Enough Rock Wool & Soundproofing: Which Density (kg/m³) to Choose?
Sound Insulation: Silence and Noise Protection
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