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Sound Testing

Sound Testing for Building Regulations

We operate a nationwide, UKAS-accredited sound insulation testing programme, providing you with reports for your building control officer with a quick and reliable turnaround. 

Sound testing is required for new dwellings in the United Kingdom, or any residential conversion that creates two adjoining dwellings. Our efficient sound insulation testing protocols fully comply with Part E of the Building Regulations for England and Wales. Our years of experience mean that your project will be expertly dealt with from start to finish by our expert team of acoustic consultants. You can rest assured that you are in safe hands as we are UKAS Accredited Testing Laboratory No. 8568  for Sound Testing. 

What is sound insulation testing?

Sound testing is required to make sure that a residential development can demonstrate acceptable levels of noise attenuation performance. This includes both airborne (i.e. noise transmitted through the air, such as a conversation between people) and impact noise (i.e. noise resulting from an impact on the surface, such as footsteps on the floor). This means that sound insulation testing essentially assesses if the dwelling provides a reasonable resistance to the passage of sound.

What is involved in sound testing?

The essential purpose of sound insulation testing is to ensure that walls and floors are attenuating (i.e. reducing) an acceptable amount of noise. Part E of the Building Regulations for England and Wales, therefore, requires that various walls and floors are tested between adjoining dwellings. The exact number of walls requiring testing will vary depending on the overall size of the development. However, a typical small to medium development (of under 10 dwellings with similar construction) should require sound testing that includes 2 airborne wall tests, 2 airborne floor tests and 2 impact floor tests).

When should my development be tested?

We strongly advise that you get in touch with us at the earliest possible stage for your development to have the best possible chance of passing its sound test. However, there are certain minimum requirements in the progress of the development that will impact our ability to perform sound insulation testing and the likelihood of a development passing. Some general requirements for improving the chances of passing sound testing include:

  •  Windows & external doors must be installed, glazed and closed
  • Ventilation systems should be installed and closed
  • Internal doors should be hung
  • Walls, floors and ceilings must be completed
  • Skirting boards, electrical sockets and light switches should be fitted
  • To test Impact sound transmission, there must be no cosmetic flooring fitted
  • Rooms in which testing is to be carried out should be empty and tidy
  • No trades should be working in the dwelling during the test
  • Access to the properties on both sides of the separating partition is required
  • There must be no noisy operations around the test properties during testing
  • 240v (50Hz) mains power is required within the dwellings

How much does sound insulation testing cost?

Sound testing costs will ultimately depend on the overall size of the development. We pride ourselves on our expert and acclaimed service, which includes honesty and transparency with all costs associated with sound insulation testing.

This means that sound testing is broken down into two simple areas:

  •  a one-off ‘site fee’ which covers costs for expert engineers, equipment and reporting
  • a remaining fee based on the number of sound insulation tests required

We also provide impressive savings for bulk testing of multiple developments, as well as discounts for returning clients.

Our unrivalled service includes free, expert advice for helping properties achieve required levels of sound attenuation. 

We also charge a site fee only for developments that require re-testing. Simply the use the contact form on this page, or call our offices, to chat about your specific sound insulation testing requirements with our friendly and knowledgeable expert acoustic consultants.

What is Sound Insulation?

Sound is transmitted through most walls and floors by setting the entire structure into vibration. This vibration generates new sound waves of reduced intensity on the other side.

The passage of sound into one room of a building from a source located in another room or outside the building is termed ''sound transmission".

Transmission loss or Sound Reduction Index, R dB, is a measure of the effectiveness of a wall, floor, door or other barrier in restricting the passage of sound. The transmission loss varies with frequency and the loss is usually greater at higher frequencies. The unit of measure of sound transmission loss is the decibel (dB). The higher the transmission loss of a wall, the better it functions as a barrier to the passage of unwanted noise.

There are two types of sound insulation in buildings: airborne and impact. Airborne sound insulation is used when sound produced directly into the air is insulated and it is determined by using the sound reduction index. Impact sound insulation is used for floating floors and it is determined by the sound pressure level in the adjacent room below.

  1. Direct sound transmission
  2. Flanking transmission
  3. Overhearing
  4. Leakage

What is Airborne Sound Insulation?

When a sound wave is incidental upon a partition between two spaces, part of it is reflected and part of it is transmitted through the partition.

For single leaf structures, such as a homogenous concrete wall, the transmission follows the mass law, that is, the more massive the structure, the smaller the quantity of transmitted sound.  In case of lightweight structures consisting of multiple layers, such as a gypsum wall, the spring-mass law is applicable. If highly absorbent material such as stone wool is used as the spring in a double leaf wall, the sound insulation improves. The wider the cavity, the greater the benefit from stone wool will be. Typically, a 5 – 10 dB increase in R can be achieved with a filled cavity compared to an empty one. The figure below shows a single leaf structure and a double leaf structure with the same total weight.

Calculation of the sound reduction index R is based on test results obtained at different frequencies. The results are plotted against the reference curve between 100 Hz and 3150 Hz at 1/3-octave intervals. If the measurements are performed in situ (in a real building) the values are denoted R’. The standard test procedure is defined in EN ISO 140, where standard methods are given for both laboratory and field measurements.

The difference between laboratory and field values can be a significant number of dB depending on the construction details and workmanship.

If a partition consists of different kinds of elements – for example, a wall with windows and doors which have different sound transmission characteristics – the overall sound reduction index must be calculated.

The sound reduction index for holes and slits is nearly equal to 0 dB. The influence of holes and slits may therefore be important, for instance, at the connections between walls, at doors and windows without sealing strips, and at any necessary openings in partitions. If there is an acoustically absorbing material in the slits, it will give a higher sound reduction index for the slits.

What is Weighted Sound Reduction Index Rw?

When specifying the acoustic performance of a partition in a more general manner, it can be useful to describe the sound insulation by a single number.

The weighted sound reduction index, Rw , is a rating method given in EN ISO 717-1. This standard fits a standard reference curve to the measured sound reduction index curve

In EN ISO 717-1, a rating method is also given where the Rw value is completed by two C-terms which are applied to two models of the noise spectra for various types of noise. These two terms, Rw + C and Rw + Ctr, also include the frequency range 100 – 3150 Hz but can be extended to 50 – 5000 Hz. As industrial and traffic noise often have high sound levels which are also below 100 Hz, it is recommended that the extended frequency area is used.

The summary value, Rw + C, gives the reduction value in dBA for a spectrum with a level which is equally high in all third-octave bands. This can be used for:

  • Living activities (talking, music, radio, TV)

  • Railway traffic at medium and high speed

  • Highway road traffic travelling at speeds in excess of 80 km/h

  • Jet aircraft at a short distance

  • Factories emitting mainly medium and high frequency noise

The summary value Rw + Ctr also gives the reduction value in dBA, spectrum with low-frequency dominance such as:

  • Urban road traffic

  • Railway traffic at low speeds

  • Disco music

  • Factories emitting mainly low and medium frequency noise

What is Impact sound insulation?

An airborne source sets up vibrations in the surrounding air which spread out and, in turn, set up vibrations in the enclosing walls and floors. An impact source sets up vibrations directly in the element it strikes.

These vibrations spread out over the whole area of the element and into elements connected to it, such as internal walls, the inner leaves of external walls and floors. The vibrations in the elements force the air beside them to vibrate and it is these new airborne vibrations that are heard. 

Floors should reduce airborne sound and also, if they are above a dwelling, impact sound. A heavy solid floor depends on its mass to reduce airborne sound and on the soft covering to reduce impact sound at source. 

A floating floor contains a layer of highly resilient material which largely isolates the walking surface from the base and this isolation contributes to both airborne and impact insulation.

  • It is important to choose a suitable material and to make sure that is not bypassed with rigid bridges such as fixings and pipes. 

  • Air paths, including those due to shrinkage, must be avoided; porous materials and gaps at joints in the structure must be sealed.

  • Resonances must also be avoided; these may occur if some part of the structure (such as dry lining) vibrates strongly at a particular sound frequency (pitch) and transmits more energy at this pitch.

Impact sound insulation is calculated from measurements of the sound pressure level produced by the standardised hammer method. The results are presented as a curve between 50 – 5000 Hz. 

When calculating a single-number quantity L n,W or L’n,W the levels for the 16 frequencies are compared to the standard curve in a similar manner to the calculation of the sound reduction index. The only difference is that the deviation between the measured curve and the standard curve is in this case above the standard curve. Ln is measured in the lab whilst L’n is measured in the field. For both Ln and L’n low numerical values mean good impact sound insulation.

Also for impact sound insulation, two spectrum adoption terms Ci,100-2500 and Ci,50-2500are needed in case of a floor with wooden beams. The difference between the results of laboratory and field measurement is caused by the flanking phenomena in a building. In a real building, sound transfers not only through a structure being designed – for example, a floor – but also via connecting structures adjacent to the floor. 

What is the Mass-spring system?

The main idea behind the floating floor is the mass-spring system. The softer the spring, the better the vibration damping. The same goes with the mass – the heavier the better...

If the intermediate floor is not heavy, the floating floor does not work because the mass-spring system changes. In practice, an intermediate floor has to be five times heavier than a floating floor.

Impact noise insulation is measured using a standardised tapping machine. A good impact noise insulation L’n,w requires:

Concrete with a floating floor:

  • Heavy intermediate floor

  • Soft elastic intermediate layer

  • Heavy floating floor

The ideal mass-spring system:



At the extremes of its displacement, the mass is at rest and has no kinetic energy. At the same time, the spring is maximally compressed, and thus stores all the mechanical energy of the system as potential energy. When the mass is in motion and reaches the equilibrium position of the spring, the mechanical energy of the system has been completely converted into kinetic energy. 

All vibrating systems consist of this interplay between an energy-storing component and an energy-carrying component.

The frequency (Hz, the number of vibrations per unit time) of a mass-spring system is

Where k is the spring constant (mineral wool) and m is the mass (intermediate floor). The lower the f is, the better the insulation. So by increasing the mass or decreasing the spring constant we can achieve the best insulation.

What is Flanking transmission?

Flanking sound (or flanking noise) is sound that transmits between spaces indirectly, going over or around, rather than directly through the main separating element.

This can allow sound to transmit between spaces even though the main separating element itself provides good acoustic insulation.

Approved document E: Resistance to the passage of sound, defines ‘flanking transmission’ as, ‘Sound transmitted between rooms via flanking elements instead of directly through separating elements or along any path other than the direct path’. It defines a ‘flanking element’ as, ‘Any building element that contributes to sound transmission between rooms in a building that is not a separating floor or separating wall’.

A common example of flanking is sound transmitted between two spaces through a floor void (or even a floating screed) that runs under the separating partition, even though the partition provides good acoustic insulation preventing the direct transmission of sound.

Flanking can result from both impact sounds and airborne sounds. Any building element that penetrates or circumnavigates a separating element can result in flanking. This might include:

  • Windows and doors.

  • Flanking ceilings, floors and walls which continue past the separating element into the adjoining space.

  • Voids such as wall cavities, suspended ceilings and raised floors.

  • Penetrating joists.

  • Corridors and other circulation spaces.

  • Ductwork and pipework.

  • Sockets.

  • Poor workmanship.

Flanking should be considered early in the design stage of new developments and detailing should eliminate or minimise the inadvertent downgrading of sound insulation. Junctions between elements in particular can offer a potential flanking route if they are not carefully detailed and constructed. Good briefing, supervision and inspection on site can help to ensure that the quality of workmanship remains high so that details are constructed as designed.

Flanking can be a particular issue where adjoining spaces have different uses, such as; a lecture theatre next to an office, a private room adjacent to a circulation space, or between neighbouring houses with different patterns of occupancy and behaviour.

Flanking can be difficult to treat in older buildings, where the addition of sound insulation to one element simply reveals a flanking path through another.

Approved document E of the building regulations: Resistance to the passage of sound, sets out requirements for sound insulation between spaces and provides guidance on how to detail separating elements to avoid flanking.

BS EN ISO 10848-4:2010 provides a standard for the laboratory measurement of the flanking transmission of airborne and impact sound between adjoining rooms.

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  • ISO-9001
  •  Institute Of Acoustics
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testimonials

- Paul Hastings

★ ★ ★ ★ ★

30th May, 2017

I engaged Nova at the outset of my project (which I recommend you do) to assist with providing a detailed material specification and installation guidance. There was always someone available to help with practical enquiries and advice...

- C.G. Henry

★ ★ ★ ★ ★

29th Nov, 2017

I had Adam come round to a property which i thought was beyond repair. He gave sound advice with exact details of what needed to be carried out in the most cost effective manner. Once the works were carried out he returned, tested it...

- Andrew Youngson

★ ★ ★ ★ ★

6th Dec, 2017

I have worked with the team at nova on a number of projects and have always been very helpful and competitively priced. Highly recommend this company for any sound test and report.

- Carol Chaplin

★ ★ ★ ★ ★

14th Jun, 2017

Excellent service, engineer was very informative and helpful.  Good customer service being able to speak to knowledgeable people on the telephone when making inquires about the procedure involved for the sound testing of our property...

- Bun Bar

★ ★ ★ ★ ★

2nd Dec, 2015

Good efficient service. Recommend it to all.

Bright Construction UK Ltd

- Gavin Boby

★ ★ ★ ★ ★

9th Nov, 2015

Very attentive and friendly service, keen to serve the client, and absolutely not about dragging the case out for fees - will work to save the client fees, and understand the practicalities of the case and the opposition that applications...

- Ejaz Shah

★ ★ ★ ★ ★

9th Nov, 2016

Adam was very attentive and very professional answered all my questions and returned all calls the engineer arrived at the time agreed and again explained everything before carrying out the test , and we received our report within couple...

- Charles OKell

★ ★ ★ ★ ★

23rd Feb, 2017

Its a tricky area and you need the right support, Paul Robinson  brought Adam's team to the table and we'll be working together again in future for sure.

- Ainsley Black

★ ★ ★ ★ ★

14th Dec, 2016

Although we had followed the building reg, in terms of sound insulation the property conversion still failed the sound Test. Adam was very helpful and professional and guided us to the point that when it was retested again we passed. Would...

- Robert Buchanan

★ ★ ★ ★ ★

19th Jun, 2017

Friendly efficient and cost effective service, without complication

- Hepple Property Care Ltd

★ ★ ★ ★ ★

26th Oct, 2017

Very quick service, would recommend to others

- Ian Fairbairn

★ ★ ★ ★ ★

20th Dec, 2016

Excellent service and communication with all the members of staff we had dealings with.  A very professional approach and attitude by all.  An experience that is refreshing within the building sector and a company I could recommend...

- Daniel Cogdon

★ ★ ★ ★ ★

2nd Oct, 2017

Fast turn around and great service, recommended

- Allan Proctor

★ ★ ★ ★ ★

21st Sep, 2016

Excellent service by Adam and the team at Nova. The service they delivered was efficient, competitive and I would highly recommend them!

- Carol Richards

★ ★ ★ ★ ★

20th Jul, 2016

Having selected Nova Accoustics to perform a sound test on my latest project, I found the whole process completely professional, prompt & efficient .

The phone contact to set up the appointment was extremely  helpful...

- Michael Dickinson

★ ★ ★ ★ ★

1st Mar, 2017

Having used Nova Acoustics on several projects, I would not hesitate in recommending this company.

- Steph Openshaw

★ ★ ★ ★ ★

7th Sep, 2017

Fantastic service very quick and punctual highly recommended.

- Chris Bullerwell

★ ★ ★ ★ ★

22nd Nov, 2016

Used Nova Acoustics to sound test a property we'd converted in the Newcastle area.

Excellent service from start to finish. Professional, helpful & reliable throughout...highly recommended.

- Andrew Holmes

★ ★ ★ ★ ★

23rd Mar, 2017

Really helpful team of people and very quick service, which was greatly appreciated.

- Siying Lid

★ ★ ★ ★ ★

17th Aug, 2016

We are a small design firm and NOVA Acoustics provided very sufficient services to our clients with reasonable price. And they are quick to respond too.  Highly recommended.

- Floors By Design Leicester

★ ★ ★ ★ ★

24th Apr, 2017

Very good company, communicated all the way through.  Competitive pricing, I will be using them again in the near future.

- Stewart Greenhalgh

★ ★ ★ ★ ★

6th Jul, 2017

First Class, prompt professional service. I will recommend to other clients.

- Frank Kenny

★ ★ ★ ★ ★

5th Oct, 2017

Excellent  service so far and will be contacting them again for their services.

- Kelly Freakley

★ ★ ★ ★ ★

26th Jul, 2017

Fantastic service from this company at a very reasonable price, would definitely recomend....

- Robert Myers

★ ★ ★ ★ ★

27th Apr, 2017

I used Nova acoustics to sound test my basement flat conversion for the building control certificate

And found them to be professional and friendly. The test was done mid afternoon and I had received by six o'clock the same...

- Stephen Shaw

★ ★ ★ ★ ★

13th Jul, 2017

Excellent service. Would recommend to anyone needing assistance with matters arising from acoustics and noise.

- Rick Parsons

★ ★ ★ ★ ★

29th Jun, 2017

iKoustic have worked with Nova Acoustics for some time now and they are constantly thorough, professional and super helpful in everything they do ... They are certainly our partner of choice ... Rick

- Carl Smoult

★ ★ ★ ★ ★

10th Aug, 2017

Prompt, friendly, efficient, professional... would recommend and use again.

- Gary Oliver

★ ★ ★ ★ ★

20th Mar, 2017

As most of you reading this message are now probably aware  the difficulty of finding guidance and compliance of the part E building regulations is an arduous task. Well search no more! Adam at Nova Acoustics not only talked me through...

- Kate Whitehead

★ ★ ★ ★ ★

27th Jul, 2017

Speedy quote, arranging the testing & report! Seb was really friendly & efficient onsite. Highly recommend!

- David Hope

★ ★ ★ ★ ★

26th Sep, 2017

Came promptly at the requested time. Did the work professionally and in good time and provided the required reports so no issues or problems to report.

- Mark Girdham

★ ★ ★ ★ ★

27th Jul, 2017

NOVA provided a fast and efficient service. They came to carry out the sound tests on my 8 Bed HMO, which was a change of use from 4 flats. Very friendly and professional service. Mark (Hull)

- Simon Phillips

★ ★ ★ ★ ★

4th Oct, 2017

Excellent company, providing a professional service at a competitive price and a quick, hassle free  experience. I would recommend them to anyone.

Simon Phillips  Salisbury Poultry Ltd

- Peter Phillips

★ ★ ★ ★ ★

31st Aug, 2017

Excellent service from start to finish.

Highly professional team who where very accommodating to the team on site and worked exceptional well with everyone.

Having worked with other companies within the same...

- Claire Gannon

★ ★ ★ ★ ★

31st Oct, 2017

Excellent speedy service, Luigi was very proficient and professional at carrying out his job, a real asset to the company. Thank you Luigi. Kind Regards, Ant Mason

Clients we’ve worked with

  • ITV
  • Unilever
  • Sig
  • Leeds University
  • Morrisons
  • Taylor Wimpey
  • City of Stoke On Trent
  • Hambleton District
  • Calvert Trust
  • Aldi
  • Arnold Laver
  • Broadley
  • Engie
  • Gardiner Theo
  • Iggesund
  • Oxford University
  • PepsiCo
  • Richmonshire
  • Savills