Why can I hear my neighbours through the wall?

Why can I hear everything through my wall?

Because sound is getting through the weakest parts of the wall, or around it. A solid brick party wall is heavy, and heavy walls block sound reasonably well. But one gap, one socket box or one joist carrying vibration can let through far more noise than the rest of the wall combined.

People often tell me the wall must be paper thin. Sometimes it is, particularly in conversions and some newer homes. More often it is a decent wall with holes in its defence. That matters, because it changes what will actually help.

Is it airborne or impact noise?

Work this out first, because the two are fixed differently.

• Airborne noise starts in the air: voices, television, music, a dog barking. You hear it as sound in the room, often clearest near sockets, corners and the ceiling line.
• Impact noise starts in the structure: footsteps, doors slamming, chairs scraping, children jumping. It often feels like thuds and can seem to come from everywhere at once.

A wall lining mainly helps with airborne noise. Impact noise through shared floors and joists usually needs attention at its source, or on the floor and ceiling rather than the wall.

Where are the weak points in a party wall?

They are usually hidden behind the plaster, which is why the wall looks solid while behaving as if it were thin. The common ones are:

• Unfilled mortar joints. In older brickwork the vertical joints between bricks were not always fully filled, leaving tiny air paths straight through.
• Back-to-back sockets and switches. Each one removes much of the wall's thickness at that point.
• Chimney breasts and alcoves. The brickwork beside or behind a flue can be thinner than the main wall.
• Joists built into the wall. Floor joists from both houses often sit in the same wall and carry vibration across.
• The loft. In some older houses the party wall has gaps above the ceiling, or was never fully built up to the roof.
• Gaps at skirting and around pipes where sound leaks into the floor void.

Which homes are most likely to have noise problems?

Every house type has its own typical weak points. This is a general guide, not a rule for every property.

For context, Building Regulations in England require separating walls in new homes to achieve at least 45 dB of airborne sound insulation on a site test, and 43 dB in conversions. Many older homes were built long before any such standard existed.

What is flanking sound?

Flanking is sound that goes around a wall instead of through it. It travels along floorboards, joists, ceilings, side walls and shared voids, then comes out into your room beside the wall you were blaming.

This is why some people spend money soundproofing a party wall and still hear their neighbours. The new lining works, but the noise simply takes the next easiest route. A good survey looks for flanking paths before anything is designed, because they decide whether treating one wall will be enough.

Why does bass come through more than voices?

Because heavy walls are good at stopping high and middle sounds, and much worse at stopping low ones. Speech sits mostly in the middle range, so a solid brick wall takes the words out of a conversation and leaves a murmur. The thump of bass from a speaker or a subwoofer has long, powerful sound waves that shake the whole wall and the floors around it.

Doubling the weight of a wall only improves it by about 5 to 6 decibels, which is noticeable but not dramatic. That is why simply adding more of the same material has limits, and why good soundproofing relies on separation as well as mass: two layers that are not rigidly connected perform far better than one layer twice as heavy.

It also explains a common experience. You cannot make out what your neighbours are saying, but you can feel their music at night. The wall is doing its job on speech; the bass is going through the structure.

Why does the noise seem worse at night or after new windows?

Because there is less other sound to hide it. During the day, traffic and household noise mask much of what comes through the wall. At night, or after you fit new double glazing that cuts out street noise, the background drops and your neighbour's television suddenly seems much louder, even though it is not.

What can I do about noisy neighbours right now?

Start with the cheap steps and the conversation, then decide whether building work is justified.

1. Talk to your neighbour calmly. Many people have no idea how much you can hear, and a speaker or television moved off the shared wall can make a real difference.
2. Listen at different spots to find where the noise is loudest: sockets, corners, floor edges, the ceiling line.
3. Seal gaps at skirting boards and around pipes, and check for back-to-back sockets.
4. Look in the loft for gaps in the party wall.
5. Put heavy furniture, such as a full bookcase, against the shared wall.
6. If the noise is excessive and persistent, your local council's environmental health team can investigate whether it amounts to a statutory nuisance.

When is soundproofing worth it?

When the noise is affecting your sleep or your enjoyment of a home you want to stay in, and the cheap steps have not done enough. Many people reach a point where they feel the only choices are soundproofing or moving. Soundproofing is a significant investment, but it is usually far less disruptive than selling up.

The best results come from a design based on how the sound is actually travelling. My guide on how to soundproof a wall explains the systems, space and cost, and my wall soundproofing page covers how I survey and plan the work. If you would like to talk it through, you can get in touch for a free home visit.

Common questions