A Guide to Soundproofing Materials

There is a wide variety of materials that may be used for soundproofing purposes. The appropriate choice will depend on the intended minimisation or elimination of sound. Soundproofing materials are commonly installed either for the purpose of improving the sound quality within a room or reducing the level of sound leakage to adjacent rooms and areas. Soundproofing options include foam sheeting and acoustic insulation.

What is Soundproofing and How Does It Work?

Soundproofing is a method for the reduction of sound pressure in relation to a particular sound source and receptor. It may also be referred to as decibel reduction, sound insulation, or acoustic insulation. The installation of soundproofing should result in the reduction of decibels (dB) or absorption of sound. There is a variety of soundproofing materials, each suitable for distinct applications. The use of soundproofing products is recommended whenever you want to minimise the level of sound that is being generated in a different space, room, or enclosure from your own.

Soundproofing can be an effective means of suppressing unwanted indirect sound waves including the reflection of echoes, resonances, and reverberations. It can also be used to reduce the transmission of undesirable indirect sound waves that would otherwise be highly noticeable to an involuntary listener.

Soundproofing may be applied to either residential or commercial properties. In the first instance, the aim will be to reduce or completely eliminate the input of sounds from outside sources. Residential soundproofing is commonly focussed on existing structures, such as windows and doors. As a result, standard soundproofing options include the fitting of curtains and double-paned windows. Exterior windows may also be fitted for improved soundproofing in some instances.

Similarly, soundproofing can be applied to commercial buildings such as restaurants, schools and office buildings for the reduced disturbance of staff and customers. It is quite common for soundproofing technologies to be included in the design of open-plan offices to minimise noise and help with worker productivity. Such technologies might also be included in areas where confidential discussions are regularly held.

Soundproofing materials enable the minimisation of sound in the following ways:

• Blocking airborne noise through the addition of mass to a structure and resulting in the reflection or conversion of sound energy into heat

• Separating or dampening the impact noise between structures and minimising the circulation of sound vibration/energy

• Absorbing sound that would otherwise reverberate and echo within a contained space

Soundproofing Materials – What are They?

As mentioned, there is a wide variety of soundproofing materials, each suited to different applications. The best choice will depend on the desirable noise minimisation, a level which is normally indicated in the form of a dB rating. It’s also worth keeping in mind that soundproofing materials will only be as strong as their weakest point.

The dB rating typically equates to the level of sound reduction achieved on the transmission of sound through existing materials and added soundproofing. Soundproofing materials can be fitted for the effective minimisation of noise in a wide variety of environments.

Consider the varieties of soundproofing highlighted in this table:

	Product	Material	Benefits	Typical Uses
	Foam soundproofing sheet	Polyurethane foam	High levels of sound absorption and insulation Facing protection against dust and moisture Chemical resistance	Panelling of machinery Engine rooms Close-fit canopies
	PVC soundproofing sheet	Solid PVC sheeting	High mass noise barrier Effective sound absorption and insulation	Various domestic and commercial applications
	PUR soundproofing sheet	Polyurethane foam	High levels of sound absorption and insulation Facing protection against dust and moisture Resistance to chemicals	Pump enclosures Engine rooms
	Adhesive bitumen soundproofing mat	Black, flexible bitumen or plastic panels made to industrial standards	Dampens and reduces body vibrations and air noises in metals and plastics	Various domestic and vehicle applications

Soundproofing Foam

Soft and lightweight soundproofing foam is designed for the absorption of natural sound waves and the prevention of noises generated as a result of contact on hard surfaces (such as walls and ceilings). This involves the conversion of sound energy into heat and minimisation of the sound waves that may circulate through a room. Such foam may also be fitted for the purpose of improved sound quality, particularly within music studios. The thickness and density of the foam will have a direct bearing on the penetration of sound.

Soundproofing Panels

Soundproofing panels are ideally suited to the deadening and dampening of sound in restaurants, offices, and other types of commercial space. Such panels are made from high-density acoustic plasterboard, effectively preventing the transfer of sound between rooms. Available options include fabric-wrapped, perforated wood, and water-resistant panels, depending on your requirements. Panels like these are designed for a range of purposes including the absorption of sound waves, clarification of speech, and limitation of reverberation through interior spaces. They are equally suitable for domestic and commercial applications.

How to Soundproof Walls

There are two main varieties of wall that people are commonly keen to soundproof. The first type is the solid standard party wall, constructed with a brick or block formation. The other type is the internal stud wall, usually consisting of a timber frame and plasterboard insulation. Higher levels of soundproofing are typically required for properties featuring stud walls. It is quite common to fit soundproof panels and construct acoustic walls for soundproofing against noisy neighbours. Such methods may also be used to effectively soundproof a bedroom.

The first key step when soundproofing a stud wall will be to carry out a check for any gaps or weak points. These can be filled with acoustic sealant for improved security. The process may then continue with the improvement of walling mass and the addition of acoustic insulation between the timber battens. It is advisable to use a combination of materials for the limitation of noise at different frequencies.

Soundproofing a Wall

The highest level of soundproofing can be achieved by creating a room within a room, separate from the external structure. This may also be referred to as acoustic de-coupling. It involves the elimination of vibration transferred between solid materials and through the air. However, it is important to account for safety implications, ensuring a reasonable degree of ventilation and avoiding the use of gas heaters.

Alternative methods for soundproofing walls include the installation of thin sound panels and complete acoustic wall systems. Soundproofing panels allow for the effective minimisation of sound without the need to sacrifice any interior space. However, a combination of materials should be used in instances requiring a high degree of soundproofing. High density acoustic insulation slabs can be fitted for sound absorption and the limitation of reverberation. You also have the option of fitting stud walling, with different levels of thickness and insulation to suit the depth of existing stud walls.

How to Soundproof a Room

You might be keen to soundproof an entire room for a range of reasons. It might be that you want to create a separate creative space, where you can maintain full concentration without disturbance. Alternatively, you might be creating a home entertainment space, in which the sound should be fully enclosed. Whatever the case, there is a range of soundproofing options to consider.

The process of soundproofing a room should begin with the identification of any noise sources. This will have a bearing on the appropriate choice of soundproofing solution. The variety and intensity of the noise should also be taken into account. Different soundproofing materials are suited to solid and stud walls, as explained above.

The first step in the soundproofing installation process will be to add mass to the walls. This might involve the addition of recycled cotton batts or sound isolation systems. The ceiling should be the next area of the room to be soundproofed. Soundproofing insulation may be fitted between the joists of a ceiling in the process of construction. Alternatively, acoustic panels may be fitted between the tracks of the soundproofing system of an existing ceiling.

Ideally, it will be possible to soundproof the floor from above. The installation of acoustic flooring will allow for the most effective minimisation of noise produced when people walk or move furniture across the floor. Improved soundproofing can be achieved through the installation of acoustic floating floors.

UK Noise Laws and Regulations

The soundproofing requirements for new homes and conversions are set out in part E (Resistance to Sound) of the UK Building Regulations. This covers the division of walls and floors. Sound insulation requirements are also covered. It will be necessary to install a range of acoustic products for compliance with part E of the regulations. The soundproofing of flooring, floor joists, and the ceiling must all be ensured. The regulations specifically state that internal airborne sound resistance inside any dwelling must be a minimum of 40dB. Impact sounds must also be limited to 62dB for set floors and stairs in new builds as well as 64dB in conversion projects.

The table below highlights the basic sound insulation values for residential buildings.

For reference, DnTw describes the airborne sound insulating capabilities of an on-site building element. It relates to all physical channels of transmitting sound such as through partitions, ceiling voids, and external walls. Conversely, Rw is the weighted sound reduction index (measured in decibels) and it describes the airborne sound-insulating capabilities of a particular element of a building. LnTw references impact sound insulation, and lastly, Ctr is the correction factor.

New builds, conversions, and buildings scheduled for alternative use will be subject to testing in accordance with the values set out in the table. If the values are exceeded, then remedial work and re-testing will be required.

The regulations specify the need for there to be some type of acoustic insulation between the flooring joists. The fitting of such insulation will result in the increase of mass and the minimisation of airborne sound. The ceiling should also be boarded with two layers of acoustic plasterboard. Acoustic underlay mats will be sufficient for the soundproofing of floors complete with sub-flooring. An acoustic underlay may be added to ensure compliance with the soundproofing standards.

What are the Different Types of Noise?

There are three primary types of sound that can be minimised with soundproofing materials.

How to Measure Sound

A variety of factors may have a bearing on perceived and actual levels of sound. The period of exposure, frequencies (or pitches), and the environment will all have some impact. Sound intensity (otherwise referred to as sound power or pressure) is measured in decibels (dB). You should be aware that sound is measured in logarithmic terms, relating to the physical sensation felt upon hearing. A gradual increase in sound level will result in greatly increased intensity and perceived loudness.

Sound levels may also be measured in terms of weighted decibels (dBA). Such measurement is directly associated with the impact on hearing health. It relates specifically to the intensity of sound and impact on the human ear. Small increases in the dBA level can have a significant impact on your hearing.

There will be a greater risk of hearing damage on exposure to:

• 85 dBA for a period of at least 8 hours

• 100 dBA for at least 14 minutes

• 110 dBA for at least 2 minutes

The frequency of sound is measured in terms of the number of sound vibrations per second. A person with optimum ear health can hear sounds of frequencies between 20 Hertz and 20,000 Hertz. There are various types of electronic equipment that can be used for the purpose of measuring sound levels in dB and dBA.