Types of Sound Insulation Testing Needed on Flats

What Types of Sound Insulation Testing Are Needed on Flats?

One question clients regularly ask is: “What types of sound insulation testing are needed for flats?”

If you’re building a new block of flats or converting an existing property into separate dwellings, sound insulation testing is an important part of the Building Regulations process.

Under Approved Document E (ADE), separating walls and floors need to provide a suitable level of protection against noise travelling between homes. This includes everyday sounds such as conversations, television, music and footsteps.

The exact testing requirements depend on whether you’re dealing with a new-build development or a conversion. Still, two main types of sound insulation testing apply: airborne sound testing and impact sound testing.

Airborne Sound Insulation Testing

Airborne sound testing looks at how effectively a wall or floor stops sound travelling through the air.

Typical examples include speech, television, music and general household noise.

Where are airborne sound tests required?

Testing may be required between:

• Living rooms in neighbouring flats
• Bedrooms in neighbouring flats
• Living rooms and bedrooms
• Separating floors between flats

Airborne testing applies to both new-build flats and conversion projects.

How does an airborne sound test work?

During the test, a high-powered dodecahedron loudspeaker generates pink noise in one room. Class 1 sound meters then measure the sound levels in both the source room and the receiving room.

The results are used to calculate the airborne sound insulation performance, expressed as DnT,w + Ctr.

Minimum performance requirements

For residential developments, the typical minimum requirements are:

• New-build flats: ≥ 45 dB
• Conversions: ≥ 43 dB

These figures are an important part of demonstrating compliance with Approved Document E.

For a more detailed explanation, see our guide to Airborne Sound Testing.

Impact Sound Insulation Testing

Impact testing is slightly different. Rather than measuring sound travelling through the air, it measures noise created by physical impact on a separating floor.

Think about footsteps from the flat above, a chair being moved, or an object being dropped on the floor.

Where are impact tests required?

Impact testing is required for separating floors between dwellings, including conversions where a new flat is created above or below another dwelling.

How does impact testing work?

A calibrated tapping machine is placed on the upper-flat floor. The machine repeatedly drops a series of metal hammers onto the floor in a controlled pattern.

A Class 1 sound meter measures the resulting noise level in the room below.

The lower the measured result, the better the floor controls impact noise.

Minimum performance requirements

Typical limits are:

• New-build flats: ≤ 62 dB
• Conversions: ≤ 64 dB

If you’re dealing with an existing or upgraded floor, it’s particularly important to consider the floor construction and acoustic build-up before work starts.

For more information, see our guide to Sound Testing Floors in Flats.

Sound Testing Requirements for New-Build Flats

For a typical new-build flat development, you will generally need to consider:

• Airborne testing of separating walls
• Airborne testing of separating floors
• Impact testing of separating floors

The number of tests required depends on the size and layout of the development, as well as the different types of separating construction being used.

For example, a small block may typically require something along the lines of:

• 2 airborne wall tests
• 2 airborne floor tests
• 2 impact floor tests

However, confirm the exact testing schedule for each project rather than relying on a standard number of tests.

What about Robust Details?

If a development is constructed in accordance with an applicable Robust Details specification, sound testing may not be required for those particular separating elements.

However, you must follow the relevant Robust Details specification correctly, including the required registration and construction details. If the construction differs from the specification, testing may still be required.

Sound Testing Requirements for Conversion Flats

Conversions can be more challenging from an acoustic perspective.

Older buildings were not necessarily designed with the same levels of sound insulation expected between modern dwellings. Existing floors and walls can therefore perform very differently from one property to another.

For conversion projects, the required testing can include:

• Airborne wall testing
• Airborne floor testing
• Impact floor testing

Why test before construction?

For conversions, we often recommend pre-construction sound testing where appropriate.

Testing the existing structure before carrying out acoustic upgrades can help establish how well the existing floor or wall performs. You can then use this information to determine what improvements are likely needed.

It can be much more cost-effective to identify an acoustic problem before installing the new floor or ceiling than to discover it during the final compliance test.

For further guidance, see our article on Designing for Sound Insulation.

Pre-Construction and Post-Construction Sound Testing

Sound insulation testing can be useful at different stages of a project.

Pre-construction testing

Pre-construction testing is particularly useful on conversion projects.

It allows you to assess the existing construction before acoustic upgrade work begins. The results can then help inform the design of the proposed floor or wall build-up.

Post-construction testing

Post-construction, or pre-completion testing, is carried out once the relevant construction work has been completed.

These tests provide the results needed to demonstrate compliance with Building Control where testing is required.

For a more detailed explanation of the process, see our guide to Pre- and Post-Construction Sound Insulation Testing Methodology.

Sound Testing for Lease Conditions and Hard Flooring

Building Regulations aren’t the only reason you may need sound testing in a flat.

Some lease agreements, particularly in London, include acoustic requirements for flooring alterations. This is especially common when replacing carpet with timber, laminate or engineered wood flooring.

In these situations, an acoustic assessment or sound testing may be required before and/or after the flooring is installed.

Depending on the lease and the requirements of the building, this could involve:

• Pre-installation airborne and impact testing
• Acoustic assessment and design advice
• Installation of an appropriate acoustic floor system
• Post-installation verification testing

Check the lease requirements before starting work. Getting the acoustic requirements right at the design stage can help avoid problems later.

For more information, see our guide to Sound Testing and Acoustic Design for Lease Conditions.

Why Choose APT Sound Testing?

At APT Sound Testing, we work with developers, builders, architects, landlords and property professionals across London and the South East.

Our services include:

• UKAS-accredited testing laboratory status
• ATTMA Level 2 certification
• More than 22 years of experience in acoustics and sound insulation testing
• Specialist experience with London and South East developments
• Fast site attendance, often within 24–48 hours
• Same-day certification
• In-house sound testing engineers rather than subcontractors
• Additional services including air testing, thermal imaging and diagnostic smoke surveys

Because our engineers test a wide range of residential projects, we can often identify potential problems quickly and provide practical advice on what may need to be addressed.

The aim is simple: help you get the testing right and avoid unnecessary project delays.

Need Sound Insulation Testing for a Flat?

Whether you’re developing a new block of flats, converting an existing property or carrying out alterations to a leasehold flat, getting the acoustic requirements right early can save time and money.

If you need sound insulation testing in London or the South East, or you’d like advice about acoustic design and compliance, get in touch with APT Sound Testing.

Email: info@aptsoundtesting.co.uk
Phone: 07775 623464
Website: www.aptsoundtesting.co.uk

We can often attend sites within 24–48 hours, with certificates available the same day where appropriate.