Internal walls & partitions

Sound insulation of partition walls using dry construction

Last updated: 14 October 2026

Sound insulation of partition walls using dry construction: mass, stone wool, decoupling and sealing. New wall or loose cladding of an existing wall, with layer

The system at a glance

Solutions & Applications · Sound insulation

Sound insulation of a partition wall — whether existing or new — does not require thick brickwork. A properly designed dry construction wall achieves higher sound reduction than a conventional brick wall twice as thick, provided that four factors are combined: mass, absorption, decoupling and airtightness. If one is missing, the construction fails.

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New or existing partition wall?

Case study	Solution	What determines the outcome
New partition between flats or offices	Dry construction wall with a CW 75 or 100 frame, stone wool and a double board on each side	Slab mass, full void, track
Very high standard (studio, meeting room, doctor’s surgery)	Double independent frame or double slab with ISOLFON BARRIER	Complete separation of the two sides
Existing brick partition wall	Free-standing cladding in front of the wall: self-supporting framework, cavity, stone wool, double slab	The new framework must not rest against the old wall

On an existing partition wall, bonding plasterboard cladding does not help — it often worsens the acoustics at speech frequencies. The explanation lies in the ‘Dry Construction Wall Cladding’ solution.

The principle: mass – spring – mass

A dry construction wall functions acoustically as a mass–spring–mass system. The panels on either side are the masses, whilst the stone wool in the cavity acts as the spring that dampens the energy. If the cavity is empty or the two sides are rigidly connected, the sound finds a path — however good the board may be.

That is why a ‘thick’ wall is not necessarily quiet — whereas a thin, properly designed one can be.

The 4 parameters

Mass: the right board. A standard plasterboard is rarely sufficient. Knauf SILENTBOARD DFR has a high-mass core (~17.9 kg/m² at 12.5 mm) and excels at low frequencies — bass, machinery, speech. Alternatively, Piano DF or DIAMANT DFH1IR. Double layer on each side, with offset joints.
Absorption: complete void filling. FIBRANgeo B-050 stone wool (αw 1.00, A1) fills the entire void — without gaps and without compression, because when compressed it ceases to act as a spring.
Decoupling: no rigid bridges. Track tape on the back of each UW, on floors, ceilings and walls. For maximum performance, the viscoelastic ISOLFON BARRIER membrane (EPDM 3.5 / 5 / 10 kg/m², asphalt-free) is inserted between the two slabs to dampen low-frequency noise.
Waterproofing: sound passes through wherever air passes. Sealing of the perimeter, floor and ceiling finishes, penetrations and electrical boxes. An unsealed joint just a few millimetres wide can negate an otherwise precise construction.

Layering as required

Level	Framework & spacing	Slabs per side
Basic — offices, rooms	CW 75 · stone wool · track tape	1 × Piano DF
Reinforced — partition walls	CW 75 or 100 · stone wool · track membrane	2 × SILENTBOARD or DIAMANT
High — studios, doctors’ surgeries, meeting rooms	CW 75 or 100 or double framework; stone wool	2 slabs with ISOLFON BARRIER in between
Existing wall	CW/UW loose-fill insulation with air gap; stone wool	2 slabs, with or without BARRIER

For example, according to the ISOLFON documentation: a plasterboard wall with a metal framework, mineral wool and BARRIER 5 between two layers of plasterboard on each side achieves Rw(C;Ctr) = 56(-4;-11) dB; masonry with plasterboard cladding and BARRIER achieves Rw = 60 dB.

ARGYNET Note

The most common mistake is not the choice of board — it is acoustic ‘short circuits’: electrical boxes back-to-back in the same cavity, unsealed perimeter ends, a shared track without elastic tape, and a cladding frame that rests against the old wall.

Sound insulation does not stop at the wall. If the noise is impact-related — footsteps, knocks from the floor above — work needs to be carried out on the floor, using a floating floor in ISOLFON ReRub.

At ARGYNET, we design the layering according to the required level of sound insulation and calculate materials per m². The Rw value is always taken from the system’s certified data sheet — not from the sum of the individual materials.

Mistakes that cost

Incorrect	Consistency
Empty shell	The gap acts as a resonator and may amplify the noise
Compressed stone wool	It loses its elasticity; it ceases to act as a spring
Aligned joints in the double layer	A seamless journey for sound
Socket boxes positioned opposite each other in the same location	A hole in the structure — sound passes through it
Without track tape	Lateral transmission from floor and ceiling
Adhesive cladding on an existing partition wall	Same or poorer acoustics