Rain noise is transferred to us in the form of sound waves. During rainfall, a variety of frequencies relating to the impact of raindrops on the roof surface are produced. The existing roof structure will be acting as a soundproofing material in some capacity but perhaps rain noise control was not a primary consideration when the roof in question was constructed. When confronted with attempting to soundproof a roof against rain noise, the first consideration will most likely be to add acoustic materials to combat the range of frequencies of sound (rain noise), that is emanating from the roof structure. Any structure will vibrate at certain frequencies, the roofing panels be they metal or composite will behave like a drum skin and when impacted will produce sound. Is it not logical therefore to introduce acoustic treatment materials that are designed to tackle this noise problem head-on.
The conventional approach would be to add mass to the roof. We all know intuitively that a thicker roof or wall will inhibit the propagation of noise (sound waves). So make the roof thicker to attenuate the noise level produced by rainfall, is this not the obvious answer? The most well-known law of soundproofing is the Mass Law. This states that by doubling the weight of the acoustic barrier you will gain approximately a 6dB improvement in sound attenuation. In other words, if you doubled the size of a brick wall, for instance, you would obtain around a 30-40% improvement in soundproofing. Likewise with a roof, but now we have to consider the additional loading we are about to introduce, can the roof support this additional loading and at what cost and at what effort?
OR SHOULD WE BE LOOKING AT THIS PROBLEM FROM A DIFFERENT PERSPECTIVE?Adding mass to the roof is being considered to address the problem of rain noise AFTER it has occurred. An alternative solution would be to prevent the rain noise BEFORE it occurs. Silent Roof Material (SRM) does exactly that as it is installed on the OUTSIDE of the roof on top of the existing roof surface intercepting the falling rain. Furthermore, SRM only weighs 800gms per square metre, any roof structure should be able to support this minimal addition. So instead of adding mass, how is the Silent Roof approach going to work?
Silent Roof Material (SRM) is a unique product that in simple terms quietly shatters falling raindrops on its upper smooth surface without transferring the impact noise produced to the roof surface beneath. The rainwater then trickles through the lattice of the SRM then drips quietly onto the original roof surface and away into the rainwater drainage system. Silent Roof will stop the great majority of rain noise on any roofing structure to a mere whisper. The material is black in colour and is UV stabilised. Due to the flexible properties of the material it can be utilised on any surface be it flat or curved. We have developed various means of securing the material to a variety of surfaces.>