HOW TO SOLVE NOISE PROBLEMS GENERATED BY POOLS ON ROOFS

Installing a swimming pool on a rooftop of a buildings is a luxury which is becoming increasingly more popular. But this dream for one can turn to an acoustic nightmare for others. Pools are a significant source of noise and vibration, when this noise is transmitted to homes located just under them this can prove to be a big inconvenience for their inhabitants.

In order for a Sound wave to be transmitted it requires a medium to travel through. The problematic point here is that the transmission through the water is faster than through air and it also has a lower energy loss.

This is because water, unlike air, is incompressible which reduces the absorption of the waves to its minimum.

Due to such a good sound transmission, the walls and bottom of the pool receive all the perturbations that occur inside it. This leads to an “amplification effect” which transmits this sound through the structure of the building, this effect is most noticeable in the homes which are in the immediate vicinity of the pools.

Based on measurements carried out in homes under the pools, the following graph shows how there is a high level of energy within the low frequency range. Frequencies between 20 and 63Hz are highlighted, this particular range can be really irritating for the inhabitants that live near pools.

AMC-Mecanocaucho offers, as an official Getzner distributor, a simple anti vibration solution that highly reduces the transmission of noise and vibrations that are transmitted through the structure.

The solution consists of an elastic suspension of the structure containing the pool with Sylomer® and Sylodyn® materials. This solutions is very easy to install and does not hinder the traditional process of building the pool.

The acoustic isolation is achieved by lining the entire base area with a Sylomer® elastic layer, this layer covers all of the surface where the structure for the pool will be built.

Building an elastic suspension for the pool´s structure is necessary, ensuring it covers both the floor and the walls to ensure that the elastic decoupling is complete and to avoid any possible acoustic bridges. Depending on the required acoustic isolation level, the natural frequency required for the suspension would be defined.

The excellent results provided by this solution have been tested and proven, both nationally and internationally to fulfil the most strict acoustic standards.

Installation video

Isolation values in a real case with Sylomer®

The following example consists of a real application in which acoustic isolation has been achieved with a Sylomer® lining. This swimming pool on a roof has been made for a building company of Gipuzkoa.

This company, which carried out the construction of the building, set up the structure for the pool without any acoustic isolation that would elastically decouple this structure from the building.

Once the building was ready, inhabitants begun to move into their houses and would be seriously affected by the noise and the vibrations that were transmitted from this pool. Because of this issue the building company received a complaint from the surrounding neighbourhood.

The building company ended up losing the case and was forced to take action to acoustically isolate the pool. In this case, the pool was a prefabricated pool of polyester, so it could easily be lifted up and Sylomer placed underneath it.

However, this is not the case for concrete pools made in-situ, as lifting up this type of pools is really a complicated and expensive task.

As a possible alternative a second interior structure should be made elastically decoupled from the first. This would however reduce the dimensions of the pool and dependent on structural calculations even lead to the closing of the pool.

To gather evidence for this case a measurement was carried out while the pool was rigidly mounted, this demonstrated the existence of the problem and the following result was obtained:

45 dB(A) + 9 dB(A) of impulsive and low frequency penalties = 54 dB(A)

A second measurement was carried out after the legal case and after the Sylomer lining was installed to show the improvement given by this type of solution, the following results were obtained:

34 dB(A) + 3 dB(A) of impulsive penalties = 37 dB(A)

Taking into account that the dB scale is a logarithmic scale, used in acoustics to simplify the range of sound pressure or vibration accelerations, this 17dB reduction means an attenuation in sound and vibration of an 85%.

References

More buildings in which this solution has been applied are shown in the following table:

Calculation software for the selection of Sylomer®

AMC Mecanocaucho has the software for the study of the type of Sylomer® required for each application. It is also possible to combine different densities of material in the same study.

Do not hesitate to contact our application engineers for more information on this product.