Glued thermo-acoustic linings are part of the category ofinterior thermal insulation called ITI.
As the name suggests, insulation is carried out inside the living space, as opposed to external insulation systems (ETIS). This type of insulation is common in renovations and has both advantages and disadvantages.
The benefits of'ITI are many :
But the ITI also have cons :
Bonded thermo-acoustic linings are not ITIs like the others.
Un thermally bonded lining made of by plaque (usually plaster) and a insulating (polystyrene, polyurethane, glass wool, etc.).
It is fixed to the wall with glue dots. La installation is simple and fast, ideal for renovations.
Once installed, simply make the joints, sand and apply a paint or wall covering. Add joint strips and careful smoothing for an optimal finish. It is also important to treat the thermal bridges and technical points (sockets, switches) to ensure effective insulation.
Sound insulation is defined as the difference between the noise level upstream and downstream of a wall.
It depends on several factors such as the composition of the wall (single, double, etc.), the characteristics of the materials and the mechanical connections.
In the case of single walls Like concrete walls and glued laminated timber floors, sound insulation is generally related to the surface mass and Young's modulus. Generally, the heavier the wall, the better the sound insulation.
In the case of double walls (plasterboard partitions on frame), several phenomena occur.
In fact, these walls make up a mass-spring-mass system. LThe masses are the facings (plasterboard) and the spring is made up of the air gap (or glued insulation) between the walls. The resonant frequency of this system depends on the “stiffness” of the air gap or insulation and the surface mass of the walls.
Diagram – Mass – Spring – Mass
The sound insulation of double walls is greater for a much lower mass, une past the resonance frequency mass-spring-mass (often at low frequencies). That's all.The advantage of double walls compared to single walls!
Acoustic insulation of a single and double wall
The acoustic performance of the linings is assessed in the laboratory (ISO 10140) on standardized walls (concrete wall, concrete block, brick) or specific walls (for example for a new wall product).
To obtain the reduction in sound insulation provided by the lining, measure the insulation with the lining (R1 – wall + lining) and without the lining (R2 – wall alone) and the difference between the 2 measurements (ΔR=R2-R1).
When this ΔR is negative, the doubling degrades the performance of the wall.
If it is positive, it improves the acoustic performance of the wall.
Standard linings, particularly for rigid insulation, can degrade the acoustic insulation of the wall in two ways:
The different noise transmission pathways
The thermo-acoustic linings have the advantage of playing on these 2 transmissions:
Several factors in the composition of the linings influence the acoustic performance:
Dynamic stiffness depends on the material and its manufacturing process. For example, polystyrene will have different dynamic stiffnesses than polyurethane or glass wool insulation.
In the context of climate change, efficient thermal insulation is essential in homes. This translates into a reduction in heating (or air conditioning) and therefore in raw materials.
However, many insulation products come from the petrochemical industry and even if recycling is increasing, new innovations are needed to reduce the ecological impact of the manufacture of these materials.
New ideas are emerging with bio-sourced materials, recycling, using fewer materials (with the same thermal performance), and improving manufacturing processes. All of these new opportunities must not be achieved without considering acoustic performance, in order to ensure a peaceful thermal and acoustic environment for future home users.
