Noise Action Week 2012

Understanding Noise and How to Reduce Its Impact

Noise awareness is about recognising how everyday sound affects other people and understanding the practical steps that can reduce unnecessary disturbance.

Music, televisions, conversations, footsteps, machinery, traffic and barking dogs can all become noticeable beyond the space in which they originate. In some cases, the issue is mainly behavioural and can be improved by reducing volume or changing when and where an activity takes place. In others, the construction of the building allows normal levels of sound to travel too easily between rooms or neighbouring properties.

Home soundproofing and commercial acoustic treatments can help reduce noise, but they should be selected according to the source, level and transmission path of the sound.

No single product can solve every noise problem. Walls, floors, ceilings, doors, windows, ventilation routes and structural connections may all contribute, so the first step is to understand what type of noise is involved.

What Is Noise Awareness?

Noise awareness means considering how sound travels beyond the room or property in which it is created.

Simple actions can sometimes make a useful difference, including:

• Keeping music and television at a considerate level
• Moving speakers away from shared walls
• Using isolation pads beneath audio equipment
• Adding rugs or suitable underlay to hard floors
• Avoiding furniture movement during quieter hours
• Maintaining alarms, fans and mechanical equipment
• Closing doors and windows during louder activities

These measures may not correct a weak separating structure, but they can reduce the amount of sound entering it. Soundproofing should support considerate behaviour rather than be treated as permission to generate unlimited noise.

Airborne Noise and Impact Noise

Most building noise can be described as airborne noise, impact noise or structure-borne vibration.

Airborne noise

Airborne noise travels through the air before reaching a wall, floor, ceiling, door or window. Examples include:

• Conversations and raised voices
• Music, televisions and radios
• Dogs barking
• Traffic and aircraft
• Office conversations and telephones
• Machinery and household appliances

Reducing airborne noise commonly involves adding suitable mass, closing gaps and introducing separation between layers of the construction.

Impact noise

Impact noise is created when something makes direct contact with part of a building. Typical examples include:

• Footsteps on hard floors
• Furniture being moved
• Objects being dropped
• Exercise equipment
• Doors closing

The impact creates vibration that can travel through joists, concrete slabs, walls and ceilings. Resilient floor layers or isolated ceilings may be needed to reduce this type of sound.

Structure-borne vibration

Speakers, washing machines, pumps, fans and other mechanical equipment can transfer vibration directly into the building.

The source may need to be isolated from the surrounding structure using suitable mounts, pads or supporting systems. Adding acoustic panels to the room would not address this type of transmission.

Find the Main Sound Path

Noise does not always travel directly through the most obvious surface. It may pass around a wall or ceiling through connected parts of the building.

Common transmission routes include:

• Party walls and internal partitions
• Floors and ceilings
• Timber joists and structural beams
• Suspended ceiling voids
• Loft spaces
• Doors and door frames
• Windows and glazing
• Ventilation openings and ducts
• Pipes, cables and service penetrations

Sound that bypasses the main separating surface is known as flanking transmission. For example, a party wall may be upgraded while noise continues to travel through the connected floor or ceiling.

A successful project therefore needs to consider the complete room and the surrounding building construction.

Reducing Noise Through Walls

Voices, music and television noise are frequently heard through shared walls. A suitable wall soundproofing system may combine acoustic insulation, additional mass, resilient fixings and sealed perimeter joints.

The appropriate build-up depends on whether the existing wall is masonry, lightweight blockwork, timber stud or another form of construction.

Possible elements include:

• Acoustic insulation within a cavity
• Resilient bars or isolation clips
• Independent wall linings
• Dense acoustic boards
• Flexible acoustic sealing at the perimeter

JCW Silent Board Plus may form part of certain wall or ceiling systems, but it should not be considered a complete solution on its own. The supporting structure, cavity treatment, fixings and installation quality all affect the result.

Floors and Ceilings

Footsteps, furniture movement and airborne noise can travel between storeys.

Where impact noise originates from above, treating the floor close to the source is generally preferable. A suitable floor soundproofing system might include an acoustic underlay, resilient deck or floating floor arrangement.

Where the upper floor cannot be accessed, ceiling soundproofing may help. This could involve insulation between joists, resiliently mounted boards or an independent ceiling.

An independent ceiling can provide greater separation but will reduce the available room height. Lighting, alarms, ventilation and service openings also need careful detailing.

Floor and ceiling treatments may be less effective where vibration continues to travel through surrounding walls or structural elements.

Doors, Windows and Ventilation

Doors and windows are often lighter and less airtight than the walls around them. However, they should only be upgraded where they are confirmed as significant weak points.

A soundproof door relies on the complete doorset, including the door leaf, frame, perimeter seals and threshold. A gap beneath the door can significantly reduce performance.

External noise may enter through windows, particularly where the glazing is lightweight or the seals are damaged. The glass thickness, spacing between panes, frame condition and ventilation openings all affect acoustic performance.

Ventilation routes should not simply be blocked. Homes, offices and commercial buildings require adequate airflow. Acoustic vents, attenuators or redesigned duct routes may be needed where ventilation is an important sound path.

Gaps and Service Penetrations

Small openings can weaken the acoustic performance of a wall, floor or ceiling.

Areas to inspect include:

• Gaps around pipes and cables
• Board edges
• Junctions around skirting boards
• Electrical sockets
• Openings into floor or ceiling cavities
• Poorly sealed window and door frames

A flexible acoustic sealant can be used around appropriate joints as part of a complete system.

Sealant alone will not soundproof a weak wall or floor. Its role is to close air paths that could otherwise reduce the effectiveness of the main construction.

Service penetrations may also require suitable fire-stopping measures. Acoustic work should never compromise the fire resistance of a separating surface.

Noise in Flats, Apartments and HMOs

Noise transmission can be more complicated in flats and converted properties because several homes may share walls, floors, ceiling voids, beams and service routes.

A sound that appears to be passing directly through one wall may actually have travelled through a floor slab, loft space or connected partition.

Our guidance on flat and HMO soundproofing covers some of the common issues found in multi-occupancy buildings.

Before alterations are made, lease restrictions, permissions, fire compartmentation and building requirements may also need to be considered.

Workplace and Commercial Noise

Noise awareness is equally important in offices, restaurants, leisure venues and other commercial spaces.

In an office, the problem may involve conversations passing between meeting rooms, external traffic or excessive reverberation in an open-plan space. The office soundproofing approach should reflect whether the aim is to reduce transmission or improve internal acoustic comfort.

Restaurants and entertainment spaces may need treatment to walls, ceilings, doors and ventilation systems, as well as internal absorption to control reverberation. Information on leisure and entertainment soundproofing explains some of these considerations.

Soundproofing and Sound Absorption Are Different

Soundproofing helps reduce noise passing from one space to another. Sound absorption reduces echo and reverberation within the same room.

Acoustic foam, wall panels and ceiling rafts can make a room sound less reflective and improve speech clarity. They should not be relied upon to block noise through walls, floors or ceilings.

Some rooms require both treatments. A meeting room, studio or restaurant may need soundproofing for separation and absorption for better internal acoustics.

Installation Quality Matters

Even correctly selected products can underperform when they are installed badly. Common problems include:

• Rigid fixings bridging resilient layers
• Unsealed board edges
• Compressed acoustic insulation
• Untreated sockets and service openings
• Incorrectly fitted perimeter strips
• Gaps around doors, ducts or pipework

Some systems may be suitable for a competent DIY installer. More complex independent walls, suspended ceilings, floating floors and commercial projects may require an experienced installer or tradesperson.

Set Realistic Expectations

Soundproofing can reduce unwanted noise, but it cannot guarantee complete silence or remove every disturbance.

Results depend on:

• The source, volume and frequency of the noise
• The building construction
• The number and severity of weak points
• Flanking transmission
• The system and products selected
• The standard of installation
• How the space is used after the work is completed

Low-frequency music, mechanical vibration and heavy impact noise are often more difficult to control than ordinary conversation. A realistic aim is usually a meaningful reduction rather than complete elimination.

Choose the Correct Acoustic Treatment

Before ordering soundproofing products, identify whether the problem involves sound transmission, internal reverberation, impact noise or equipment vibration.

A targeted system based on the building and the main sound path is more likely to provide useful results than applying unrelated materials to every available surface.

Call Acoustic Supplies on 01204 548400 or contact the team online to discuss your soundproofing project.