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When you’re dealing with unwanted noise in your home or workplace, understanding the type of noise you’re facing is the first step toward finding the correct solution.

When it comes to soundproofing, not all noise is created equal.

Two of the most common types you’ll encounter are impact noise and airborne noise, but what exactly is the difference between them?

Whether you’re tired of thumping footsteps from the floor above or frustrated by hearing voices coming through the walls, this guide will help you understand what’s causing the disturbance; and more importantly, how to address it effectively.

We’ll break down the science behind these noise types and walk you through proven methods to reduce both, using professional-grade soundproofing materials.

What is Impact Noise?

Impact noise, sometimes referred to as structure-borne sound, is created when an object physically strikes or makes contact with a surface.

That surface, often a floor, wall, or ceiling, vibrates and transmits the sound energy through the building structure.

A common example is the sound of someone walking across a hardwood or tiled floor.

Each footstep generates energy that travels through the floor, down into the ceiling below, and ultimately into your ears.

Unlike airborne noise, which travels through the air, impact noise travels through materials.

Typical examples of impact noise include:

• Footsteps on a floor above
• Furniture being moved or dropped
• Doors slamming
• Objects falling on hard surfaces
• Bouncing balls

Because of its direct contact with the building’s structure, impact noise can be particularly difficult to isolate if not addressed properly.

What Causes Impact Noise?

Impact noise is caused by vibration energy transferring directly from a solid object into a solid surface.

This energy causes the surface to act like a loudspeaker, sending vibrations through the walls, floors, and ceilings of a building.

The degree of impact noise is influenced by:

• The type of flooring (e.g. hardwood floors create more noise than carpets)
• The construction method (e.g. timber joist floors transfer more noise than solid concrete slabs)
• The presence or absence of insulation or underlay

Lightweight, rigid construction materials typically transmit more impact noise than heavier, denser materials.

That’s why you may notice more noise in newer buildings that use lightweight timber frames compared to older properties built from thick masonry.

What is Airborne Noise?

Airborne noise is sound that travels through the air, as the name suggests.

It’s produced when soundwaves from voices, music, televisions, or traffic pass through the air and hit walls, ceilings, windows, and other surfaces which in turn results in Structural airborne noise – a sound that travels through the air and contacts a surface or solid.

If these surfaces aren’t properly insulated or soundproofed, the noise can pass right through.

Common sources of airborne noise include:

• People talking or shouting
• Music or television
• Dogs barking
• Traffic and outdoor noise
• Household appliances

Airborne noise is often the more noticeable of the two types, especially in semi-detached or terraced homes where neighbouring properties share walls.

How Does Sound Travel?

To fully understand the difference between impact and airborne noise, it’s helpful to know how sound travels.

Sound is a vibration that moves through a medium; usually air, but also solids and liquids.

When a sound source produces vibrations:

• Airborne sound travels as pressure waves through the air. These waves hit surfaces and try to pass through them.
• Impact sound travels as vibrations within solid structures, like floors and walls, and radiates as sound when it reaches another surface.

This difference in transmission method is why soundproofing strategies must be tailored to each type.

You can’t block impact noise with exactly the same approach as you would use for airborne noise, and vice versa.

How Impact Noise Differs to Airborne Noise

Here’s a simple way to understand their key differences:

• Impact noise starts with a physical force on a surface.
• Airborne noise starts with soundwaves in the air.

In practice:

• Impact noise is often low-frequency, thudding, and harder to block using traditional insulation.
• Airborne noise is usually higher-frequency, like voices or music, and travels more easily through gaps and lightweight materials.

Another key difference is that impact noise doesn’t need air to travel.

It can move straight through concrete, timber, or steel, whereas airborne noise requires a medium like air to move from one place to another.

Is Flanking Noise Caused by Impact Noise?

Flanking noise is slightly different, but it often includes elements of impact noise.

It refers to sound that travels along indirect paths through a building’s structure, rather than straight through a wall or floor.

For example, sound may bypass a well-insulated wall by travelling along the structure of the said wall or a connected floor or ceiling.

So even if a wall has excellent airborne sound insulation, noise can still “flank” around it.

Impact vibrations can easily become flanking noise, especially in rigid structures without isolation materials.

This is why soundproofing a single element (like a wall) might not be effective if the floor and ceiling connections aren’t also addressed.

How to Soundproof Against Impact Noise

To combat impact noise effectively, you need to reduce vibration transmission at the source.

That means introducing materials that absorb, thermally convert or interrupt the vibration path before it spreads into the structure.

Here’s how you can soundproof for impact noise:

1. Install an Acoustic Underlay

Using a dense acoustic underlay beneath flooring is one of the most effective ways to reduce impact sound from footsteps or dropped objects.

Acoustiblok AcoustiMat Acoustic Underlay is an excellent solution.

It acts as a shock absorber, breaking the direct contact between the floor surface and the structural floor beneath.

2. Add a Specialist Acoustiblok Isolation Layer

Under or within floor build-ups, adding the product Acoustiblok 3mm Isolation Membrane can significantly reduce structure-borne sound transmission.

Despite being just 3mm thick, it converts sound energy through thermal transfer into trace amounts of heat, stopping noise in its tracks.

3. Float the Floor

Creating a “floating floor” by decoupling it from the subfloor can help absorb vibrations.

This typically involves combining underlay, acoustic membranes, and resilient layers.

4. Seal All Gaps

Any gaps or seams can allow both impact and airborne noise to escape.

Use Acoustiblok Acoustic Sealant to create a completely sealed perimeter.

For membrane joins, use Acoustiblok Jointing Tape to ensure full coverage and effectiveness.

How to Soundproof Against Airborne Noise

Airborne noise requires a slightly different approach.

Instead of absorbing vibration, the goal is to block or absorb soundwaves in the air.

1. Increase Levels of Acoustic Isolation of Walls, Ceilings & Floors

Adding specialist acoustic isolation membranes to convert acoustic energy into a less problematic heat energy makes it harder for soundwaves to pass through.

Acoustiblok Isolation Membrane can be fixed within walls, ceilings, or floors to introduce this unique process without taking up significant space or reengineering the entire project.

2. Decouple the Structure

Using acoustic clips or resilient bars, you can separate layers of wall or ceiling.

This breaks the path of vibration and makes it harder for airborne sound to travel.

3. Add Sound Absorption

Within cavities (like stud walls), using an open cell cavity material with a higher density like Acoustiblok QuietFibre can dramatically reduce sound energy within the void. This material also prevents or certainly reduces the effect of resonance and amplification which would certainly happen if the cavity is left as an open (cave like) space.

It works similarly to Rockwool but is purpose-designed for acoustic applications.

4. Add Mass

Incorporate additional layers of higher density finishing board to your wall and ceilings or alternative suitable board for the floors.

5. Seal Gaps and Penetrations

Airborne sound will find its way through the tiniest cracks.

Apply Acoustiblok Acoustic Sealant around electrical boxes, skirting boards, and pipe penetrations to ensure airtightness.

Conclusion

Understanding the difference between impact noise and airborne noise is crucial for identifying the right soundproofing solution.

While airborne noise moves through the air and is easier to block with materials such as Acoustiblok 3mm Isolation Membrane, mass, density and airtight seals, impact noise moves through physical structures and yet again requires Acoustiblok 6mm Isolation Membrane to convert energy to provide vibration isolation to combat.

Both types of noise can be tackled with the right approach, and a mix of the right materials.

Acoustiblok offers high-performance solutions such as the Isolation Membrane, AcoustiMat underlay, QuietFibre insulation, and acoustic sealants and tapes to help you create a quieter, more peaceful environment, whether at home or at work.

If you’re struggling with unwanted noise, identifying the source and applying the right solution can make all the difference.

Get it right, and you’ll enjoy not just a quieter space, but a better quality of life.

Speak to one of our soundproofing experts if your building is experiencing impact noise.