However, this does not always mean that neighbors are behaving exceptionally loudly. The cause may be insufficient insulation of a wall or ceiling, a workmanship defect, a lack of airtightness, or the transmission of vibrations through the building structure. Before looking for a way to soundproof an apartment, it is therefore necessary to determine what type of sound we are dealing with and how it reaches us.

In this article, you will learn:

1. Why neighbors can be heard in an apartment.

2. The difference between airborne and impact sounds.

3. Whether neighbors are heard more from above, from below, or through the wall.

4. How to identify the noise transmission path.

5. Which solutions can help, and which only improve interior acoustics.

Why are neighbors so easily heard in apartment buildings?

Sound can reach an apartment through various paths. Sometimes it passes directly through the wall separating two premises. Other times, it vibrates the floor slab and structural elements, and then appears in a room seemingly unrelated to the source.

This is why, based on hearing alone, it is not always possible to correctly identify where the noise is coming from. Sound heard at one wall may originate from an apartment located above, below, or even across the hallway.

The audibility of neighbors is influenced by, among other things:

• the structure and mass of walls and ceilings,

• the method of connecting building elements,

• floor layers,

• doors and their seals,

• ventilation ducts,

• installation penetrations and electrical boxes,

• gaps and execution errors,

• the occurrence of acoustic bridges.

The thickness of the wall alone is therefore not sufficient to evaluate its effectiveness. The materials, layer layout, quality of workmanship, and flanking transmission paths of sound also play an important role.

Airborne, impact, and structure-borne sound

Identifying the type of noise is the first step in choosing the right solution. Minimizing conversations coming from behind a wall requires a different approach than addressing footsteps transmitted through a ceiling.

Airborne sounds

Conversations, music, television, a dog barking, or a crying baby are examples of airborne sounds. The sound wave propagates in the air, reaches a partition, and causes it to vibrate. On the other side, the wall re-emits the sound into the room.

Noise can also bypass the main partition and penetrate through doors, ventilation grilles, gaps, or installation openings.

The ability of a wall, ceiling, or door to limit such penetration is described by sound insulation. The more effective and well-constructed the partition, the less sound energy reaches the neighboring room.

Impact sounds

Footsteps, jumping, falling objects, and moving furniture directly excite the floor and ceiling. The resulting vibrations propagate through the building structure and can be heard not only in the apartment located directly below the source.

Impact sounds are a specific type of structure-borne sounds. Reducing them primarily requires minimizing the amount of energy transmitted to the structure.

Flexible layers under the flooring, appropriate underlays, and a correctly designed floating floor help in this regard. More on evaluating ceilings can be found in the material explaining what impact sound level is.

Flanking transmission

Noise does not always pass directly through the wall separating two apartments. It can bypass it through the ceiling, side walls, facade, installation shaft, or structural joints.

This phenomenon is called flanking transmission. In practice, this means that even a partition with good parameters may not provide the expected comfort if the sound finds an easier path through adjacent building elements.

For the same reason, adding insulation to a single, randomly selected wall does not always bring a noticeable improvement.

Are neighbors heard more from above, from below, or through the wall?

It cannot be assumed that the neighbor from above is always heard best. Everything depends on the type of sound and the building construction.

Footsteps, children running, and moving furniture are usually most disruptive in the apartment located below the source. This is because the impacts directly excite the floor and ceiling.

Conversely, conversations, music, and television sound can reach you from above, below, or through the wall. If there is strong flanking transmission, the direction perceived by the resident does not necessarily indicate the actual location of the source.

In a building with a rigid, connected structure, vibrations can travel a much longer path than intuition suggests. Therefore, before installing insulation, it is advisable to confirm which partition and which transmission path are actually responsible for the problem.

How to identify the source of noise?

An initial assessment can be made based on the nature of the sound and the circumstances in which it occurs.

It is also helpful to note:

• when the noise occurs,

• how long it lasts,

• where it is best heard,

• whether it is accompanied by perceptible vibrations,

• whether it changes after closing doors, windows, or ventilation grilles,

• whether the problem occurs in all rooms.

Such documentation cannot replace physical measurement, but it can help an acoustician narrow down the possible causes more quickly.

What to do when footsteps and moving furniture can be heard?

In the case of impact sounds, the most effective approach is to limit vibrations at the source. An appropriate flexible layer under the screed, an underlay under the floor finish, or a correctly constructed floating floor can reduce the amount of energy transmitted to the ceiling.

The method of execution is of key importance here. If the flooring layer is rigidly connected to a wall, installation, or other structural element, an acoustic bridge may form, weakening the effectiveness of the entire solution.

It is much more difficult to combat footsteps solely from the side of the apartment located below. A suspended ceiling constructed using an appropriate system can help, but its effectiveness depends on the structure, the connections used, and the contribution of flanking transmission. Simply gluing a thin material to the ceiling usually does not solve structural vibration problems.

Furthermore, one should not attribute a single, fixed improvement value in decibels to every floating floor. The actual effect depends on the ceiling structure, the layers used, the type of source, and the quality of execution.

What to do when conversations, TV, or music can be heard?

If speech can be clearly heard through the wall, the entire partition should be checked, not just its central part. Weak points can include:

• gaps near the floor or ceiling,

• electrical boxes placed on both sides of the wall,

• cable and pipe penetrations,

• doors with insufficient insulation,

• ventilation ducts,

• incorrect connection of the wall to the ceiling.

The solution may involve installing an additional insulation system, increasing the mass of the partition, or using a structure decoupled from the existing wall. However, such cladding occupies part of the apartment's floor space, so its thickness and construction must be tailored to the actual problem.

In the case of renovation, a properly designed wall acoustic insulation system can be considered. However, it should not be chosen solely based on where the noise seems loudest. First, ventilation, gaps, and flanking transmission must be ruled out.

Will acoustic panels soundproof a neighbor?

Sound-absorbing panels improve acoustic conditions inside a room. They reduce reflections, shorten reverberation, and can make the interior quieter and more comfortable.

However, this does not mean they will automatically block conversations or music coming from behind the wall.

Acoustic treatment and acoustic insulation serve two different purposes:

• acoustic treatment limits sound reflections inside a room,

• insulation limits sound transmission between rooms.

Excessive reverberation can increase the perceived annoyance of noise that has already entered the interior. Reducing it will improve comfort, but it will not eliminate the cause of sound penetrating through the wall or ceiling.

When are acoustic measurements needed?

If the noise is persistent, the source remains unclear, or a costly insulation system is planned, it is advisable to conduct measurements before starting work.

Depending on the problem, it is possible to evaluate, among other things:

• the insulation of a wall or ceiling against airborne sounds,

• the level of impact sounds transmitted through the ceiling,

• noise originating from installations,

• the impact of gaps and flanking paths,

• compliance of the obtained parameters with relevant requirements.

Measuring insulation requires a controlled sound source and access to both the source and receiving rooms. The result should be interpreted in relation to the type of building, construction of partitions, and the scope of applicable requirements.

More information can be found on the page regarding airborne sound insulation measurements.

A proper approach still matters

Not every noise problem immediately requires rebuilding a wall or reporting the matter to the administration. Sometimes neighbors are simply unaware of how easily music, conversations, or the sounds of moving furniture can be heard in another apartment.

If the situation permits, it is best to start with a calm conversation. It helps to point out the specific type of noise and the hours when it is most disruptive. A general statement like "you are too loud" can trigger a defensive reaction, whereas info like "after 10 PM, the shifting of chairs can be clearly heard in the bedroom" is easier to understand.

Simple adjustments, such as using soft pads under furniture, putting a rug where a child plays, moving a speaker away from the wall, or reducing bass in the evening, can bring a noticeable improvement.

At the same time, research conducted in multi-family buildings shows that perceived annoyance is influenced not only by the sound level itself. Its predictability, individual sensitivity, and relations between neighbors also play a role [3, 4]. This does not mean that the problem exists solely in our perception. However, it shows that technical solutions and communication should often complement each other.

Diagnosis first, solution second

If footsteps, conversations, or music from neighbors can be heard in your apartment, it is not advisable to start with a random purchase of foams, panels, or mats. What helps with reverberation will not necessarily improve wall insulation. Conversely, a solution effective for conversations may not handle vibrations caused by footsteps.

First, the type of noise, its likely source, and its transmission path must be determined. Only then can it be decided whether a simple change at the source is sufficient or if intervention in the floor, wall, or ceiling will be necessary.

Good acoustics begin with a correct diagnosis. Only this allows for designing a solution that not only looks convincing but actually mitigates the problem.

Bibliography

1. Regulation of the Minister of Infrastructure on the technical conditions to be met by buildings and their location, in particular § 323 and § 326: text of the legal act.

2. Polish Committee for Standardization, PN-B-02151-3:2015-10, "Building acoustics — Protection against noise in buildings — Part 3: Requirements for acoustic insulation of partitions in buildings and building elements": description of the standard.

3. Park S.H., Lee P.J., Yang K.S., Kim K.W., "Relationships between non-acoustic factors and subjective reactions to floor impact noise in apartment buildings", The Journal of the Acoustical Society of America, 2016: PubMed.

4. "Contributors to Neighbour Noise Annoyance", 2021: PubMed.