Noise pollution is incredibly frustrating. Whether it’s from road traffic, railway networks, aircraft or just plain old noisy neighbours, measures can be taken to increase the soundproofing capabilities of your home. External wall insulation is excellent for soundproofing. Not only does EWI improve the thermal performance of your property, but certain types of insulation can also dramatically improve a building's acoustics. We will discuss the negative impact of noise pollution on human health and which external wall insulation system is best for preventing this.
What are the effects of noise pollution?
Noise pollution has proven to significantly affect children, adults and the elderly. According to research carried out by Rockwool, noise pollution can cause stress and fatigue due to disturbed sleep patterns. In turn, this can lead to health problems and a slower rate of development for children. Noise pollution can also cause high blood pressure, heart disease, and increased stress levels.
Reducing noise pollution is possible internally by reducing noise from appliances and media devices. But what about the things you can't control, like those pesky neighbours or that nearby airport? Turn to external wall insulation.
Best insulation for soundproofing
If you live in a solid-wall property, it’s unlikely that your home will be adequately soundproofed. Generally, homes are built with insulation in the walls (cavity wall insulation) which absorbs the sound and protects the house against noise pollution. External wall insulation is a great choice if you live in a solid-walled property. Given that it can be installed on walls with CWI, you can benefit from both systems.Mineral Wool insulation is the best one to go for if soundproofing is a concern. Renowned for having excellent insulating capabilities, the insulation reduces the amount of noise entering your home. Acoustic insulation is far more effective as it is installed externally. The entire insulation system seamlessly envelopes the house and is, therefore, a highly effective solution against sound pollution. We recommend using the Mineral Wool insulation at a thickness greater than 200mm. Of course, with a Mineral Wool external wall insulation system, it’s not just the soundproofing capabilities that you reap the rewards of. Mineral Wool has excellent thermal insulating capabilities, is class A1 fire-rated (the highest standard!), and is breathable. EPS insulation
system also provides minor soundproofing benefits at a fraction of the cost of Mineral Wool. However, it performs poorly in terms of fire rating.
How does sound insulation work?
Sound insulation is broken down into three parts:
- Absorption: Fibrous or porous materials, such as Rockwool, are particularly effective at absorbing sound waves. These materials work by converting the sound wave energy into heat, which reduces sound transmission through the structure.
- Reflection: Dense and solid materials often act as barriers that reflect sound back toward its source. Concrete walls, for instance, effectively reflect sound, but materials that are purely reflective are generally not the most effective choice for sound insulation on their own.
- Dissipation: Certain advanced materials can dissipate sound energy by scattering it in various directions. While traditional insulation materials don't typically offer this property, it is a growing area of research in soundproofing technology.
How is external wall insulation soundproofing measured?
Various countries have building codes and standards dictating the minimum acoustic insulation requirements. For instance, the UK has regulations for sound insulation between dwellings in the form of Approved Document E of the Building Regulations. These documents specify the minimum STC and NRC ratings for different types of buildings and applications, ensuring a baseline acoustic comfort standard.
- Noise Reduction Coefficient (NRC): This measures a material's ability to absorb sound, with values ranging from 0 (no absorption) to 1 (complete absorption).
- Sound Transmission Class (STC): This assesses a material's effectiveness in blocking airborne sound transmission, with higher values indicating better soundproofing capabilities.
Mineral Wool (Rockwool):
- NRC: Mineral wool exhibits high sound absorption properties, with NRC values typically between 0.90 and 1.05, depending on thickness and density.
- STC: When used in wall assemblies, mineral wool can achieve STC ratings up to 68, indicating excellent sound-blocking performance.
Expanded Polystyrene (EPS):
- NRC: EPS is not primarily designed for sound absorption and generally has low NRC values, often around 0.10 to 0.20.
- STC: EPS provides minimal soundproofing benefits, with STC ratings typically ranging from 20 to 30, depending on installation and assembly.
Kingspan Kooltherm K5:
- NRC: Kingspan K5 is engineered for thermal insulation and does not significantly contribute to sound absorption, resulting in low NRC values.
- STC: Similar to EPS, Kingspan K5 offers limited soundproofing, with STC ratings generally between 20 and 30, contingent on the specific wall assembly.
How is the insulation installed?
If you are new to the idea of external wall insulation, it’s very simple!
- Mineral Wool is secured to the external wall in two ways. Premium Basecoat adhesive and with metal pin mechanical fixings.
- Once the boards are secured to the wall, the Premium Basecoat is again applied on top and fibreglass mesh is embedded within the basecoat for extra crack resistance and tensile strength.
- Once the basecoat is dry, a render primer is painted on and left to dry.
- After this, a thin coat render is applied to the basecoat to create a decorative finish.
- The overall result is a higher-performance building in many respects and an aesthetically pleasing, brand-new finish!
