Whatever floats your floor - Exploring floating floors for different applications

Whatever floats your floor – Exploring floating floors for different applications

In 1960s America, a team of acoustic consultants working with a television broadcaster approached Mason Industries with a very specific problem. Columbia Broadcasting System (CBS) wanted a new recording studio capable of quietly hosting a small herd of live elephants. The jack up floating floor system was invented to solve this problem. However, not everyone has to deal with elephants, so the floating floor design must be flexible enough to meet a range of requirements, explains Tom Van Dongen, project engineer at Mason UK.

When it comes to reducing the spread of noise in commercial buildings, needs vary. Some places want to keep noise out, some want to keep noise in, and some want to do both.

Elephants are a special case, but consider a gym where machines are clanking and weightlifters are dropping weights on the floor, or imagine a bowling alley where balls and skittles are rolling around for several hours a day. The visitors to either might not mind the noise, but there’s a risk of it carrying to other parts of the building. For example, the shockwaves from bowling balls or dumbbells hitting the floor can travel through the structure of the building and manifest as sound elsewhere.

In noisy areas like the examples above, a client might need to isolate at source to protect adjacent rooms and buildings

Silence is golden

Some businesses depend on silence for success. Think of a recording studio or a high-end spa. Here, preventing incoming structure borne vibration is key. In London, for example, much of the spaces built below ground level are close to the Underground, and noise from the trains can come up through the ground 24 hours a day. The deeper you dig, the louder they get.

There are also situations where both inbound and outbound noise must be addressed. Modern cinema systems, for example, use multiple speakers to deliver an immersive sound experience typically spanning the entire audible spectrum for humans.

A barrier

In a similar way to how strategically clearing a strip of land in a woodland can slow the spread of forest fires, removing rigid connections in a building’s structure can reduce the propagation of sound and vibration. In a room, that’s done by installing an additional floor above the building structure and supporting it on flexible, acoustically transparent mounts made of rubber or steel springs. This creates a floating floor, with no rigid connections between it and the building’s structure.

Take the gym example. In the weightlifting area, you would install a secondary concrete floor a few centimetres above the structural slab and support it on springs. When a weight is dropped on the floor, the movement of the springs themselves mitigates the low frequency, high energy pulses created by the impact before it can disturb building occupants below.

At cinemas, screens are usually adjacent to each other, so sound can easily cause disturbance. This, combined with the potential impact any external noise would have on the audience’s enjoyment, makes cinemas a special case. Here, the floating floor alone tends to be insufficient.

A box-in-box design provides the highest level of isolation. The box-in-box design involves not only isolating the floor, but the walls and ceiling too. This creates a completely isolated space, preventing propagation of vibration in any direction.

Another consideration is ensuring the system works under lighter loads, or when rooms are empty. Isolators need compression to work, but in a cinema the load varies according to how many viewers are present. It’s important that any solution works just as well with a single patron as it does in a sold-out screening and has the durability to provide a good lifespan.

Choose your mount

Theoretically, springs offer the best acoustic isolation performance, reacting instantly to a wide range of frequencies, but they might be unnecessary in some situations. For example, where low frequency or impact vibrations are not the problem, rubber is an equally effective option. Rubber mounts are more cost-effective due to their simpler design and offer no significant difference in isolation at higher frequencies compared to similarly rated springs.

While certain elements will be designed differently depending on the application, the principle behind each floating floor is the same. An acoustic isolation specialist can recommend the best course of action for your application, whether it’s dropped weights in a gym, an empty cinema or a herd of elephants in a recording studio.