Sound insulation

Jol Berg of Isover looks at the insulation solutions available for separating walls, internal walls and internal floors, and how glass mineral wool can offer the best all-round solution.

With an intense scrutiny on the energy efficiency of homes over the last decade, the focus for building insulation has been on its thermal performance. However, as the agenda shifts towards achieving a deeper understanding on how our environment affects our health and well-being, there is now an increasing emphasis on how products can enhance the acoustic performance of our buildings too.

Whether people live in a busy city, a quiet suburb or even in the middle of the countryside, they will find it almost impossible to enjoy peace and quiet all of the time. From noisy neighbours, high trafficked roads, the humming of central heating or kitchen appliances, to the noise that building occupants can make, a home can encounter a variety of sounds which are not just annoying, but can also have a major impact on the health and well-being of those living in the property.

According to the World Health Organisation, excessive noise can seriously harm human health and interferes with people’s daily activities at school, work and at home. It can disturb sleep, cause cardiovascular and psychophysiological effects, reduce performance and provoke annoyance responses and changes in social behaviour.

With this in mind, it is vital that both housebuilders and developers ensure that careful consideration is given to all building materials to ensure that a comfortable environment is created for future residents, and that the acoustic performance of a property exceeds the Building Regulation standards.

In England and Wales, acoustic performance is covered by Approved Document Part E of the Building Regulations, which stipulates the minimum standards for sound reduction and absorption qualities in homes and schools. For example, the minimum requirement for separating walls within a new dwelling is to reduce airborne sound by 45 dB. With this level of sound insulation people would strain to hear loud speech in the neighbouring property. However, there are products available on the market which can help to exceed these standards.

Glass mineral wool

Despite glass mineral wool insulation often being viewed as a material that solely affects the thermal performance of a property, it can in fact help to significantly improve the acoustics of a building. If the correct product is specified, it can even contribute to the surpassing of Building Regulation standards as well as greatly improving levels of acoustic comfort.

Of all the insulation materials available on the market, glass mineral wool likely offers the greatest benefits. It is lightweight, easy to install, non-combustible, sustainable, provides effective thermal performance and most importantly for its acoustic performance, its porous and elastic structure allows it to absorb sound and drastically reduce the transfer of noise. What’s more, thanks to its versatility, it can also be manufactured to meet a wide range of requirements from external and separating walls to internal walls and floors, roofs and loft spaces.

For separating walls it is recommended that glass mineral wool roll be specified, which is usually compliant with many of the generic Robust Detail specifications. The Robust Details scheme was developed as an alternative to pre-completion testing for demonstrating compliance with Part E of Building Regulations, and is seen by many as a cost effective, low risk way to comply.

When it comes to internal walls, the most effective way to combat the transfer of noise is to build a lightweight partition (either timber or metal stud), consisting of two sheets of plasterboard with a layer of acoustic insulation sandwiched in between. Although the Building Regulations state that a requirement of 40 dB is mandatory, by using a mass-spring-mass partition construction it is easy for housebuilders and developers to increase it to 45 dB or even 50 dB (where loud speech cannot be heard between walls). Achieving these high levels of sound reduction will positively impact how the end users will use the home in the future, allowing them to do the things they want to do without disturbing others.

For internal floors, a mineral wool insulation is also recommended to enhance sound absorption within the floor/ceiling void in order to achieve the minimum airborne sound insulation performance (40 dB) required by Part E. Currently, there is no regulation for impact sound for internal floors, but for enhancing the acoustic comfort within homes, housebuilders are encouraged to consider ways to maximise both the airborne and impact noise performance of internal floors as well.

To ensure that future residents can go about their daily activities without disturbing people in other rooms or adjoining properties – and vice versa – it is recommended that housebuilders incorporate glass mineral wool insulation, which has high acoustic performance, during the specification stage. It is also recommended that housebuilders partner with a reputable manufacturer to receive guidance on regulations and the solutions available to them.

Jol Berg is head of technical from Isover