Soundproofing in an Apartment Renovation: Walls, Floors, Ceilings

Neighbours' noise travels through the air and through the structure. Principles for insulating walls, floors and ceilings, weak spots and common mistakes.

Noise from neighbours is one of the most common complaints in apartment buildings. Footsteps from upstairs, a television next door, conversations on the landing noticeably lower the quality of daily life. Complete silence is not achievable in every flat, but well-built insulation installed during a renovation can reduce noise considerably. To get there, you first need to understand how sound travels.

Two paths for sound: air and structure

Airborne sound comes from sources such as voices, music and television; it travels through the air, reaches a wall and makes it vibrate. Heavy, massive and airtight constructions work well against it. Even a small gap, such as a crack between wall and ceiling, seriously weakens the insulation.

Impact sound comes from footsteps, dropped objects or a nail hammered into a wall; it passes directly into the structure and spreads a long way through the building. Mass alone is not enough here; you need resilient separating layers that break the vibration path. Working out which kind of noise is bothering you is the first step to choosing the right solution.

Walls: framed systems

The most common solution for a party wall is an independent frame built a short distance from the existing wall. The frame is filled with a sound-absorbing material such as mineral wool and covered with one or two layers of plasterboard. The key principle is that the frame is not rigidly fixed to the existing wall: the studs connect to floor and ceiling through a resilient tape.

Such a system takes several centimetres of space on that side of the room. In small rooms this loss has to be accepted, and insulation should be applied only to the wall where the problem really is. Gluing thin "soundproof" panels straight onto the wall often does not deliver the expected result.

There are alternatives: building an additional layer of heavy, dense masonry against the existing wall, or using a special damping compound between two layers of plasterboard. Which option is chosen depends on the existing wall's thickness and material and on how much room space can be given up.

Floors: a floating screed

To protect the neighbour below from footsteps, a floating floor is built. In this system the screed does not touch the structural slab directly: a resilient acoustic layer sits in between, and a perimeter strip runs along the walls so the screed does not touch them. That strip is an invisible but decisive detail; if it is forgotten, sound travels through the walls again.

The underlay beneath the floor finish also plays a part. A dedicated underlay under laminate or parquet reduces both footfall noise and echo inside the room. The skirting board should be fixed to the wall, not to the floor.

Ceilings: noise from above

The most effective way to deal with footsteps from upstairs is through the neighbour's floor, but that is not always possible. On your side, a suspended ceiling is built on resilient hangers with sound-absorbing material in the void. An ordinary suspended ceiling fixed rigidly to the slab can sometimes amplify sound through resonance rather than reduce it.

Ceiling insulation reduces the room height. For that reason the decision is made together with the lighting design, because recessed lights cut holes in the insulating layer.

Windows can also be an acoustic weak point. If street noise is the problem, the glazing units and seals should be checked before insulating walls, because however much you strengthen the wall, sound will still come through a weak window.

Weak spots and common mistakes

Even the best material can lose its effect because of one small error. Points that need attention:

• sockets placed back to back on a party wall;
• unfilled gaps around pipe and cable penetrations;
• places where heating pipes pass through walls;
• ventilation ducts and shared shafts;
• the seal of the front door and the gap beneath it.

The sequence of work matters in soundproofing too. Services should be installed before the insulation so there is no need to puncture it later. Each layer should be photographed and recorded as concealed work.

Setting realistic expectations

Sound insulation reduces noise, but it cannot completely change the structural characteristics of the building. If sound arrives through the side walls, the floor and along the structure at the same time, insulating only one surface gives limited results. That is why the source of the problem is identified first, and a solution is then chosen with the budget and the space lost in mind.

Soundproofing layers disappear behind finishes, and Zaferoğlu İnşaat handles them as part of a complete apartment renovation. Note whether the noise comes through a party wall, from upstairs or along the pipes, and we will start the insulation on that surface.