Decoupling and resilient fixing
The principle
Section titled “The principle”If sound sets one side of a wall vibrating and the other side is rigidly tied to it, the vibration crosses. If the connection is resilient or absent, a large part of the vibration is lost on the way.
That is decoupling, and it is the strongest tool in light gauge steel sound insulation.
How it is done
Section titled “How it is done”Two independent frames
Section titled “Two independent frames”The strongest solution: the two sides of the wall are built on separate sections that do not touch. The vibration has no rigid path.
This is the standard solution for a party wall. Party wall.
Resilient fixing
Section titled “Resilient fixing”The lining goes onto a resilient component rather than directly onto the section. It takes less room than a double frame and gives a significant improvement.
Service cavity
Section titled “Service cavity”The second plane formed with battens decouples on its own — and solves the vapour control and the cabling at the same time. Service cavity.
A resilient strip between structures
Section titled “A resilient strip between structures”At wall-to-floor and wall-to-foundation junctions, resilient separation reduces structure-borne transmission.
What destroys the effect
Section titled “What destroys the effect”A single rigid tie
Section titled “A single rigid tie”One long screw, one continuous profile, one rigidly fixed cable tray — and the two leaves touch again.
A cavity packed with rigid material
Section titled “A cavity packed with rigid material”The cavity takes soft, fibrous material; a rigid fill forms a bridge.
Flanking paths
Section titled “Flanking paths”Sound bypasses a good wall through the floor, the ceiling and the flanking walls. So the detailing of the adjoining structures is part of the solution.
Where it counts most
Section titled “Where it counts most”- at party walls,
- between a bedroom and a corridor or a plant room,
- in floors, because of impact sound, Impact sound insulation,
- in offices, around meeting rooms.
The practical lesson
Section titled “The practical lesson”Decoupling is cheap when it is decided at design stage and expensive when it has to be sorted out afterwards. The difference is a few centimetres and a few resilient components — not a question of material cost.
The point
Section titled “The point”Good sound insulation is not more material but a better structure. Decoupling, though, only works with no exceptions: one rigid connection is enough to spoil it.