Maxiwall AAC Acoustic Performance

Maxiwall AAC wall cladding gives trades a lightweight, solid wall system with excellent acoustic performance, helping create quieter homes with less noise transfer between rooms and from the neighbours outside.

Acoustic performance in free-standing home and low-density housing has become more important in today’s home. It’s important to check the technical specifications of each product and importantly the construction method to maximise the acoustic envelope constructed.

Key technical summary on AAC acoustic performance 

1. The technical difference: AAC’s porosity makes it an efficient sound barrier per unit of mass, not a magic bullet that beats dense masonry of equal thickness. Sound insulation of a single solid leaf is governed primarily by mass per unit area (Berger’s mass law: Rs ≈ 14.5 log₁₀(m) + 10 dB).
2. The practical difference: Pound-for-pound (per kg/m²), AAC equals or beats clay brick and dense concrete. At identical thickness, denser masonry can edge ahead on raw transmission loss because it has more mass — but AAC wins on weight, structural load, buildability and thermal performance.
3. The winning detail: AAC’s real acoustic advantage is realised in lightweight composite systems — AAC + cavity + insulation + plasterboard — which exploit the mass-air-mass resonance principle to reach Rw 50+ at low total weight.

Construction professionals can sometimes confuse two distinct properties:

• Sound insulation (barrier): the ability of an element to stop airborne sound passing from one space to another. Measured as transmission loss / Rw / STC. This is what building codes regulate.
• Sound absorption: the ability of a surface to soak up sound energy within a room and reduce reverberation/echo. Measured by the absorption coefficient (α). AAC’s open surface texture gives it useful absorption — relevant to reverberant spaces such as plant rooms, car parks, gyms and pools.

Acoustic performance is how AAC panels are made 

AAC is manufactured from fine silica (sand or fly ash), cement, lime, water and a small quantity of aluminium powder. The aluminium reacts with the alkaline slurry to release hydrogen, which expands the mix like a cake before it is wire-cut and autoclaved (high-pressure steam cured). The result is a rigid mineral matrix riddled with millions of fine air cells. Because 60–70% of AAC by volume is air, its dry density is far below conventional concrete — typically 400-650 kg/m³ across AAC products generally – Big River’s MaxiWall panels are certified at 510 kg/m³ nominal dry density (50mm) and 400 kg/m³ (75mm), versus roughly 1,900–2,400 kg/m³ for dense concrete and clay brick.

International Masonry Institute, “Autoclaved Aerated Concrete Masonry Units” — AAC is 60–70% air; high surface mass plus mechanical vibration damping within the porous structure attenuates sound.

Related: the MaxiWall AAC panel system, fire rated AAC panels (party walls need both ratings) and our full AAC range.