How to Reduce External Noise Entering Your Home

Road traffic, passing pedestrians, nearby businesses, trains and other outdoor activity can all be heard inside a home. The amount of disruption will depend on the noise source, the construction of the property and the room being affected.

Soundproofing may help reduce external noise, but it is important to identify how the sound enters before deciding which products or building elements to change.

In many properties, windows, opening sections and ventilation routes allow more noise into a room than the surrounding masonry walls. Treating the wall first could therefore provide limited improvement if the glazing remains the dominant weakness.

The practical objective is usually to achieve a worthwhile reduction in the most affected rooms rather than remove every sound from outside.

What Type of External Noise Can You Hear?

Different sources produce different combinations of frequencies and sound levels.

Common external noise sources include:

Road traffic and vehicle engines
Tyres passing over wet or uneven roads
People talking or shouting outside
Music from nearby premises or vehicles
Railway lines
Aircraft
Construction activity
Mechanical plant and equipment

Voices and higher-frequency traffic sounds may be reduced differently from low-frequency engines, amplified bass or aircraft noise.

Low-frequency sound can be particularly difficult to control because it may excite walls, windows and other parts of the building structure.

Start with the Most Affected Room

It is not always necessary to soundproof an entire property.

A more practical approach is often to begin with the room where the noise causes the greatest difficulty, such as:

A bedroom facing a busy road
A home office near a railway
A living room beside a commercial premises
A nursery facing a communal outdoor area

Consider when the noise occurs, where it sounds loudest and whether it changes when windows, doors or internal room doors are opened and closed.

This can help identify whether the main route is the external façade, an opening within it or sound travelling through another connected part of the building.

Windows Are Often the Main Weak Point

Windows are frequently the weakest element in an external wall because they are lighter than masonry and contain opening sections, seals and ventilation components.

Their acoustic performance depends on:

The thickness and specification of the glass
The difference in thickness between separate panes
The spacing between panes
The construction and condition of the frame
The quality of the perimeter seals
How tightly opening sections close
Trickle vents and other ventilation openings

Not all double-glazed units provide the same sound reduction. Standard thermal glazing may not be designed specifically for acoustic performance.

Before replacing the complete window, check for damaged seals, poorly aligned opening sections and visible gaps around the frame.

Can Secondary Glazing Reduce Outside Noise?

Secondary glazing may help in suitable properties by adding a separate internal pane and creating a larger air cavity than is normally found within a sealed double-glazed unit.

Its effectiveness will depend on:

The depth of the cavity
The glass specification
The airtightness of the secondary frame
The condition of the original window
The frequency range of the external noise

Secondary glazing may be particularly useful where replacing original windows is undesirable or restricted.

Ventilation, condensation, maintenance access, planning requirements and emergency escape arrangements must still be considered.

Check External Doors and Their Seals

A lightweight or poorly fitting external door may allow noise to enter through the leaf, frame, threshold or surrounding gaps.

Areas to inspect include:

Open gaps around the door edges
A gap beneath the threshold
Damaged or missing perimeter seals
Lightweight glazed panels
Letterboxes and other openings
Gaps between the frame and surrounding wall

A soundproof door may be suitable where the doorway has been confirmed as a significant acoustic weakness.

The performance of an acoustic doorset depends on the door leaf, frame, seals, threshold, ironmongery and installation working together.

Replacing the door will offer limited value if most of the noise is entering through a large window, open vent or another part of the façade.

Do External Walls Need Soundproofing?

Substantial brick or block external walls may already provide greater resistance to sound than the windows and doors fitted within them.

However, a wall may still be a significant route where it is:

Lightweight timber or metal stud construction
Poorly insulated within its cavity
Damaged or incomplete
Penetrated by services and ventilation
Connected to lightweight roof or floor structures

Where the wall has been identified as an important route, a suitable wall soundproofing system may include acoustic insulation, resilient components, dense boards and flexible perimeter sealing.

The correct system depends on the original construction and available room space.

A new lining may require sockets, radiators, skirting boards and window reveals to be altered. It will also reduce the usable dimensions of the room.

Ventilation Can Transmit Noise

Any opening that allows air to pass can also allow sound into a room.

Possible routes include:

Trickle vents
Air bricks
Extract fans
Mechanical ventilation ducts
Open chimneys and flues

These openings should not simply be blocked. Homes require suitable ventilation for indoor air quality, moisture control and the safe operation of some appliances.

Where ventilation is a major acoustic weakness, an acoustic vent, attenuator or redesigned duct route may be required.

Any change must preserve the necessary airflow and comply with relevant building and safety requirements.

Seal Appropriate Gaps Around the Façade

Small gaps can allow a surprising amount of airborne sound to pass through an otherwise substantial construction.

Areas worth checking include:

Window and door frames
Pipe and cable penetrations
Junctions between walls and ceilings
Openings around utility services
Cracks within internal finishes

A flexible acoustic sealant may help close suitable perimeter joints as part of a wider treatment.

Sealant alone will not improve a lightweight wall or poorly performing window. Some service penetrations may also require tested fire-stopping or weatherproofing products.

Can Floor and Ceiling Soundproofing Help?

External noise does not always enter directly through the visible façade. It may travel through connected floors, roof structures or ceiling voids.

For example, noise entering a loft or lightweight roof may be heard through an upstairs ceiling. Sound may also travel along timber floor joists connected to an external wall.

Where a ceiling is an important route, ceiling soundproofing may involve acoustic insulation, resiliently mounted boards or an independent ceiling.

Floor soundproofing is more commonly used for sound travelling between storeys, especially footsteps and other impact noise.

Placing generic acoustic matting on the floor is unlikely to reduce substantial street noise entering through a window.

Can Acoustic Fencing Reduce Traffic Noise?

Acoustic fencing and barriers may help reduce some outdoor noise before it reaches the building.

Their performance depends on:

The height and position of the barrier
Whether it interrupts the direct line of sight
Its mass and construction
Whether the surface is continuous
Gaps beneath panels and around gates
Sound travelling over or around the ends

A barrier may provide a useful reduction for a ground-floor room or garden where the road and receiver are relatively close to ground level.

It may offer less benefit for an upper-floor bedroom, elevated road, railway embankment or aircraft route.

Planning restrictions, wind loading, access and the appearance of the boundary should also be considered.

Soundproofing Is Not Sound Absorption

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

Acoustic foam, fabric panels and ceiling absorbers may make a room sound less echoing, but they will not normally prevent traffic or voices entering through a window or external wall.

A room may need absorption for its internal acoustic quality, but this is separate from reducing external noise transmission.

A Targeted Room Can Offer Better Value

Treating more rooms does not automatically produce better value.

Where one bedroom or home office is clearly the priority, concentrating on its main windows, doors, ventilation routes and wall construction may be more practical than making minor changes throughout the entire property.

A whole-home project may be appropriate where several façades and rooms are affected, but the scale, disruption and cost will be greater.

The most suitable approach depends on:

The rooms most affected
The times at which noise occurs
The source and frequency of the noise
The main transmission paths
The existing building construction
The available budget

Set Realistic Expectations

Soundproofing can reduce unwanted external noise, but it cannot guarantee that traffic, voices, aircraft or other activity will become completely inaudible.

Results will depend on the original building, the severity of the weak points, the frequencies involved and the quality of the completed installation.

Low-frequency engines, amplified bass, heavy vehicles and aircraft can be particularly difficult to control.

The realistic goal is usually to make the affected room noticeably more comfortable rather than completely isolate it from the surrounding environment.

Plan Your External Noise Treatment

Begin by identifying the most affected room and checking its windows, doors, ventilation openings, walls and surrounding structural connections.

A targeted system addressing the dominant transmission route will generally provide better results than fitting unrelated soundproofing products around the entire home.

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

Remove Unwanted Sound From Your Home With Soundproofing