Acoustics: Improving acoustics in renovation solutions
Batirama.com 17/10/20130In acoustic comfort, treating walls and partitions reduces airborne noise, insulating floors and ceilings limits impact noise.
Flaws in design or execution can be rectified during a renovation, provided that a suitable solution is chosen and the appropriate materials are carefully used. The use of sound absorbers, anti-vibration accessories, and special facing panels (denser, with acoustic film between facings, etc.) improves comfort.
At the same time, reducing sound bridges by caulking the gaps and systematically treating the connections (partition-ceiling-floor, door frames, sockets, roller shutter boxes, etc.) is essential.
Diagnosis, an essential step. But above all, identifying the nature of the noise pollution (indoor or outdoor airborne noise, impact noise and/or equipment noise), their origin and their path makes it possible to identify the walls to be treated (generally, only treat them). one is not enough).
Evaluating the intensity of the perceived noise, by on-site measurement, and defining the maximum acceptable noise level makes it possible to define the insulation gain to be provided. Finally, the nature and condition of the walls to be treated, and the quality of the existing frames, are important in the choice of solutions (the ideal being a complete study carried out by an Acoustic Design Office).
Noise pollution
Noise is the number one cause of complaint in the housing sector. 54% of French people say they are bothered by noise coming from their home or neighborhood. 95% want more calm (Acoustic Observatory-IPSOS March 2012).
Practical info
Acoustic regulations: inventory
No acoustic regulations concerned buildings prior to 1970. The decree of June 14, 1969 regulated the acoustics of housing built between 1970 and 1996. The new acoustic regulations (NRA) applied from January 1996.
For the other buildings, articles R111-23-1 to R111-23-3 of the CCH (decree of January 9, 1995) taken for the application of article L. 111-11-1 of the code of the Construction and housing, set the acoustic characteristics of public buildings.
In the old buildings, acoustic insulation remains unregulated, but during insulation work, it is advisable to improve sound comfort, aiming at the minimum insulation values required by the NRA.
For interior airborne noise: 53 dB minimum; for exterior airborne noise: 30 dB minimum; for impact noise: 58 dB maximum; for equipment noise: limit as much as possible; and for common areas: reduce sound levels via absorbent coverings.
Solution 1: Insulate ceiling and floor
©Isover
The floor
To limit impact noise (the most annoying in apartments), the most effective way is to deal with the noise at the source, by isolating the floor of the offending dwelling in order to reduce the intensity of the shocks on the ground.
Advantage:
the simplest and least expensive.Limit:
slight correction (an acoustic improvement is only perceptible beyond 3 dB).
Interest:
The most effective; stable performance over time; can also insulate airborne noise.Limit:
ceiling height reduced from 40 to 80 mm; overload (100 kg/m2) not compatible with all subfloors; intervention rarely possible.The ceiling
Noise can be reduced by creating a false ceiling, suspended on a metal frame fixed to the ceiling by hangers. A fibrous insulation placed between the ceiling and the plasterboard acts as a shock absorber (mass-spring-mass effect).
Vibration transmission is reduced by the use of anti-vibration hangers or saddles. The installation of long-span frames fixed from wall to wall, allowing the false ceiling to be separated from the floor above, provides a better result.
Interest:
makes it possible to redo the electrical wiring, camouflaged in the double ceiling; reduces airborne and impact noise.Limit:
less effective than a floating floor at the noise source; reduced ceiling height; does not prevent lateral transmission. For a better result, also treat the vertical walls.Solution 2: Insulate partitions and walls
©Siniat
To limit the direct transmission of sound, a double wall sandwiching a fairly flexible insulation meets almost all scenarios (principle of “mass-spring-mass”).
Be careful when installing: for example, improperly sealing the bottom of the partition results in a loss of around 2 dB.
the insulation, glued to a plasterboard, provides the mechanical connection between the facings.
Interest:
thin solution; reduction of airborne noise and impact noise; economical.Limit:
less efficient than a counter partition on a metal frame.depending on the space available and the desired result, the plaster facing (single or double) is attached to a single frame or to a set of two uprights. Separating the two sides of the partition gives a better result.
Advantage:
the facings are separated, which transmits less sound; doubling the walls (and/or the ceiling) is an opportunity to renovate the electricity by passing the ducts without damaging the insulation.Limit:
greater loss of surface area, but with acoustic panels , thin walls perform well.Possible improvements: with a double facing (two plasterboards, if possible of different thicknesses), acoustic panels, a thicker partition, fixings that cut vibrations, peripheral joints, resilient strips, etc.
Or, a visco-elastic mass-type resilient interposed between the metal frame and the support, making it possible to produce a double sandwich (a 1st: structure - air-insulating layer; then a 2th with a plasterboard fixed to the metal frame, an acoustic damper (in paste or plate) and a second layer of plates).
Source: batirama.com / Emmanuelle Jeanson
