Before anyone recommends a single material, one question must be answered: is the noise airborne or impact? These are two different physical events with two different cures, and confusing them is the most expensive mistake in soundproofing. Add mass to a wall to stop your neighbour’s footsteps and you will have spent real money to change nothing. This guide teaches you to tell them apart — the same first step our surveyors take.
Airborne Noise — Sound That Travels Through the Air
Airborne noise begins in the air as pressure waves, then meets a surface and shakes it, passing its energy into the next room. Think of shouting at your wall: the sound crosses the air, vibrates the wall, and comes out the other side. Almost everything you’d call “noise from next door” is airborne.
Typical airborne sources in Ghana:
- Voices, television and music through a shared wall
- Road traffic and roadside horns through windows
- A generator’s droning roar
- An AC compressor on the boundary
- Church, mosque or spot noise carrying across the night air
Because airborne sound has to physically move a surface, it is defeated by making that surface hard to move — mass to resist it, decoupling so the vibration cannot bridge across a cavity, damping to kill the panel’s own ringing, and meticulous sealing so it cannot slip through gaps. This is the classic soundproofing recipe, and it drives our wall, window and door work: wall soundproofing, acoustic windows and secondary glazing, and soundproof doors and seals.
Impact Noise — Sound That Travels Through the Structure
Impact noise is entirely different. Here something strikes the building directly and the energy travels through the structure as a physical shudder — it never spends meaningful time in the air until it re-radiates into the room below or beside it. Think of knocking on the wall rather than shouting at it: your knuckle puts the energy straight into the solid material.
Typical impact sources:
- Footsteps and furniture dragging from the flat above
- Heels on a hard floor
- A dropped object or a slammed door
- Gym weights and dance-studio jumping onto the floor below
- Machinery or a pump bolted to a slab, sending vibration through the frame
The crucial point: adding mass to the ceiling below does very little for impact. The energy is already inside the structure, so you have to stop it entering or break its path. The cures are resilient underlayment and floating floors at the source, and decoupled, isolated ceilings below — the discipline behind our ceiling, floor and impact soundproofing. When the source is a machine bolted down, the answer is vibration isolation — springs and neoprene mounts that stop the shudder reaching the structure at all.
How a Survey Tells Them Apart
You can often diagnose by ear and hand. Put your palm flat on the wall or floor while the noise happens: a felt tremor points to structure-borne impact, while airborne noise you hear clearly but barely feel. Footsteps that arrive as a sharp thud regardless of how loud the room is above are impact; a conversation that gets louder and softer as the neighbour does is airborne. In practice a room often has both — a gym above you delivers impact through the floor and airborne music through the wall — which is why a proper survey measures rather than guesses, and why we design to the specific mix rather than a one-size recipe.
Why the Distinction Saves You Money
Two ratings exist precisely because the problems are separate. STC (Sound Transmission Class) grades airborne blocking; IIC (Impact Insulation Class) grades impact through floors. A wall built to a high STC can still transmit footfall badly if its floor has no impact treatment. We cover both numbers in STC, IIC and NRC Explained, and the wider picture in How Soundproofing Actually Works. One more twist worth knowing: even a perfectly built wall fails if sound is flanking around it through shared floors, ducts or sockets — see Flanking Paths Explained.
The Honest Bottom Line
Neither cure delivers silence — both deliver a measured reduction to a target, verified before and after. The value of naming the noise type correctly is that every cedi then goes to the path the sound is actually taking. That is what the free assessment is for: we measure, we feel for the tremor, we identify airborne versus impact, and we design only what your specific problem needs.
Not sure whether your problem is airborne or impact? Book a free noise assessment: +233 20 531 3333.