Acoustic Terminology F – L

Acoustic Terminology F – L 

Our previous blog explained the C-F of acoustic terminology, this blog further covers F – L.

Following on from our previous blogs which gave a brief description of

Flanking strip or edge strip

This is a resilient strip using foamed polyethylene normally 5 mm thick, which is located at the perimeter of a floor to isolate the floor boards from the walls and skirtings.

Flanking transmission

This is airborne or impact transmission between rooms that is transmitted via flanking elements and/or flanking elements in conjunction with the main separating elements. An example of a flanking element is the inner leaf of an external wall that connects to the separating ‘core’ of a wall or floor.

Flexible closer

This is a flexible cavity stop or cavity barrier which seals the air path in cavities linking adjoining dwellings.

Floating floor treatment (FFT)

This is a timber floating floor system which may use battens, cradles or platform base, all of which use a resilient layer to provide isolation from the base floor and adjacent wall elements.

Gypsum based plasterboard

This is a dry lining board applied to walls, ceilings and within floating floor treatments which has gypsum content. It may also have fibre reinforcement within the board.

Impact sound

This is sound which is propagated from a noise source through a direct

medium. An example of this is footfall on a floor.

Impact sound transmission

This is sound which is spread from an impact noise source in direct contact with a building element.


This is a strategy to limit the number and type of rigid connections between elements of construction.


This is the weighted standardized impact sound pressure level. A single-number quantity (weighted) to characterise the impact sound insulation of floors, in accordance with BS EN ISO 717-2: 1997.

If you have a project that requires our acoustic design service and/or sound insulation testing please contact us at or youhone Darren Direct on 07775623464. You can also visit our website at:


Acoustic Design Service in London

Acoustic Design Service in London.

If you have a property that has failed its sound testing in London, it may be down to number of reasons with the acoustic construction. To help our clients overcome this problem, we also offer our acoustic design service which helps clients to pass the sound testing upon completion of the acoustic upgrade. We can offer advice on cost effective wall and/or floor upgrades, also taking buildability and material cost into account. Our acoustic design reviews are easy to follow for the site construction staff.


By utilising our extensive knowledge of different materials and construction methods, we have had no sound test failures where our acoustic upgrades have been incorporated into the site construction.

London Sound testing usually needs to be carried out between pairs of rooms separated by party walls and/or floors. Most sound tests are carried out between living rooms and bedrooms as these are classed as the two main habitable rooms; however, other rooms can be used if this is not possible such as studies, kitchens and dining rooms.

To help control noise issues APT Sound Testing can undertake UKAS accredited Part E sound testing in London and throughout the South East. Our sound test engineers carry all the latest class 1 acoustic equipment. We provide full UKAS accredited air and sound testing in London, so our clients can be sure that all testing is completed to a strict ISO quality controlled standard

If you would like advice on your acoustic design service or sound testing in London, please contact us now at or call us on 07775623464.

Acoustic Terminology A-B

Acoustic Terminology A-B

Often confusion can arise from the large amount of ‘terms’ used in conjunction with acoustic design and sound insulation testing. To help with this we have made a list of the following terms along with a quick explanation:


This is the conversion of sound energy into heat, often by the use of a porous material.

Absorbent Material

This is a material that absorbs sound energy, such as acoustic mineral wool.

Airborne sound

This is sound which is propagated from a noise source through the medium of air. Examples of these are speech and sound from a television

Airborne Sound Transmission

This is direct transmission of airborne sound through walls or floors. When sound energy is created in a room, for instance by conversation, some of the energy is reflected or absorbed by room surfaces but some may set up vibrations in the walls and floor. Depending on both the amount of energy and the type of construction, this can result in sound being transmitted to adjacent parts of the building.

Air Path

This is a void in construction elements, which adversely affects the performance of sound resisting construction. Examples of air paths include incomplete mortar joints, porous building materials, gaps around pipes and shrinkage cracks – this can also effect the air tightness results.

 Bonded resilient cover

This is a thin resilient floor covering normally of minimum 3-5mm thickness, which is bonded to the isolated screed surface to reduce impact sound transmission such as footfall noise, however it has a lesser effect when it comes to airborne noise.


If you have a project that requires acoustic design and/or sound testing please let us know. APT Sound Testing will ensure you will have direct contact with the allocated acoustician from the start of the process, through to the successful completion of the sound insulation testing.

If you would like more information in regards to acoustic services, please contact us at or visit our website at:

Our Acoustic Services

Our Acoustic Services

APT Sound Testing offers a full turnkey solution for all your acoustic requirements to ensure compliance with Building Regulations Part E and achieve building control sign off for the acoustic elements of the project. This ensures your company receives professional advice every step of the way, with an on-going continual consideration of cost.

Our acoustic services consist of the following elements:

Sample Sound Insulation Testing

We visit site to undertake sample sound testing to the existing buildings walls and floors to check the sound insulation performance of the existing dividing partitions. Thereafter, once the sound levels have been established and targeted acoustic design can be undertaken to ensure compliance with Building Regulations Part E.

sound testing equipment

Acoustic Design Service

We can help develop the acoustic design of the project from the initial design scheme stage through to the precompletion sound testing. In particular we review the acoustic details to take into account the mass, isolation and absorption elements of the construction.

Site Survey Visits

We offer site survey visits which allow you (the client) and your contractor to feel confident about the outcome of testing at the end of the build. The site visits let us check that the installation teams are installing the acoustic materials as per manufacturers avoiding crucial onsite mistakes. You can often have a compliant design which still fails due to poor workmanship; the site survey visits negate the risk of sound test failure.


Sound Test Failures

If your building fails the sound testing, we can use our experience in building construction and acoustics to firstly diagnose the reasons for the sound test failure and thereafter recommend a cost-effective solution to allow you to achieve building regulation compliance.

If you have a project that’s needs acoustic design advice or sound testing in London, then please contact us at: or phone us directly on 07775623464.

Noise Complaints in Existing Apartment Blocks

Noise Complaints in Existing Apartment Blocks

Over the last few years we are noticing a rise in noise complaints in existing apartment blocks. There may be many reasons for this. Noise problems range from airborne noise transmission from voices TVs and music to footfall impact noise caused by high heels on wooden/tiled floors – it is usually the impact noise that is noticed most by the residents if the unit above has changed their floor finish from carpet to wood.


In many cases even if the floor assembly has been designed and constructed to provide adequate airborne isolation, impact noise can still be a major problem. One of the main problems is if works to the floor finish have been undertaken, changing it from carpet to timber. Even if it passes the sound test, the perceivable rise in impact noise often leads to complaints, as carpet and underlay normally provides a good degree of impact sound isolation. Taking this into account it’s very important that impact isolation design, is taken into account before the installation of a hardwood and/or ceramic tile finish.

If you think you may have a problem with sound in your dwelling and/or you have encountered complaints from a neighbour due to changes you have made to the floor finish then please contact us now. Try to describe the noise problem in as much detail as possible. Describe the nature of the sounds, when and where you or your neighbour can hear it. Is it impact noise or airborne noise or a combination of both? The more information you can provide us, the quicker we can try to determine the nature of the problem and find a solution. It may be as simple as the installation of an acoustic resilient membrane to the floor.


In our experience, if careful consideration is shown to the acoustic element of the floor upgrade, it should reduce the chance of complaints at a later stage, which will also avert costly legal battles at the end of the project and which often leads on to expensive remedial works.

We can come in prior to works commence and undertake a sample sound test of the existing floor partition, thereafter we can advise on the acoustic design of the floor. once the works have been completed we can then undertake a final precompletion sound test to show compliance with Building Regulations Part E.

If you are about to make changes to your apartment floor, and you require acoustic design advice, then please contact us now at:  or phone me directly on 07775623464.

Why have I failed my Precompletion Sound Testing

Why have I failed my Precompletion Sound Testing?

There are many reasons why dwellings fail precompletion sound testing. If the onsite construction has gaps, cracks or holes it will conduct airborne sounds and can significantly reduce the sound insulation of a construction. For optimum sound insulation a construction must be airtight. Most small gaps can be sealed at the finishing stage using Gyproc jointing compounds. Small gaps or air paths around perimeter Gypframe framework can be sealed with sealant. At the base of the partition, gaps will occur which can be filled with acoustic mastic.


The most common noise flanking pathways are as follows:

  1. Ceiling Partitions – Above and Through the Ceiling Space (where an adequate acoustic break has not been integrated within the ceiling void)
  2. Floor Partitions – Through Floor and Floor Joist Space (if insulation has not been installed or direct fixing to joists without a drop ceiling below the partition under test)
  3. Shared Structural Building Components – Floor Boards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
  4. Through Structural Steel (structural steel beams are often a major cause of noise transmission as plasterboard is often fixed directly to the steel without sound breaks)
  5. Plumbing Chases – Junctures Between the Walls & Floor Slab Above or at the Exterior Wall Juncture (this should be filed with mortar etc. to add mass to this weakened area)
  6. Through Windows (if they are no double glazed or have secondary glazing as a minimum)
  7. Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)
  8. Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic)
  9. Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)

In many instances we have found that existing floor structures of a minimum of 200mm concrete usually achieve the airborne standard as stipulated by Building Regulations Part; however, the impact results are usually poor due to inadequate acoustic insolation between the floor constructions. This is because the airborne sound is easily broken down by the mass of the concrete slab, therefore sounds such as speech & TV etc. are minimised. Unfortunately, impact sound results are poor due to the lack of isolation within the slab, therefore the sound travels straight through the slab to the area below.


To help reduce potential control noise issues APT Sound Testing can undertake an acoustic design review of the floors after sample sound testing to ensure both the airborne and impact sound tests are allowed for during our acoustic design service.

If you would like more information in regards to sound testing please follow our blog at: or contact us at: and 07775623464 or visit our website at:


Sound Testing to Office Conversions

Sound Testing to Office Conversions 

When it comes to refurbishment projects such as office block conversions or large houses subdivided into dwellings, we can undertake a sample sound test of the existing wall and floor construction. Once we have established the sound levels for the existing construction we can then look at extent of the acoustic upgrades to attain Part E Compliance. This is much more targeted way to formulate a more cost effective and accurate acoustic  design as we know the sound insulation performance of the existing partitions.

sound testing equipment

The sound insulation levels required to pass Part E are usually 45dB for airborne wall and floors and 62dB for Impact Sound Testing on new build, however sometimes a higher target may be required in-line with the Code for Sustainable Homes; this is usually in defined in the following figures +3, 5 & 8dB, this means if its plus 5dB you will need to achieve 50dB for airborne and 57dB for impact sound testing.  Obviously if you need to comply with the Code for Sustainable Homes then special attention must be shown to the acoustic design from the offset to reduce the chance of sound testing failure.

architect drafting a house blueprint

architect drafting a house blueprint

The amount of sound testing you require depends on the size of the development. All new build properties and conversions require 10% of each party wall/floor construction type to be tested, i.e. if you have built a pair of semi-detached houses you would be required to undertake 2 airborne wall tests. If you have up to 10 flats you would require 1 x 6 pack, consisting of 2 airborne wall, 2 airborne floor & 2 Impact sound tests – known as a 6 pack)  However if you have 11 units this would rise to 12 Sound Tests or 2 x 6 pack. Also, if you have many different wall or floor types you will be required to undertake more tests to satisfy Building Regulations Part E.

There are many ways to improve the chances of passing your sound test at the first attempt, they are:

  • Ensure all penetrations are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.
  • Avoid the use of lightweight blocks in the inner envelope construction as sound will travel both vertically and horizontally from dwelling to dwelling.
  • The use of resilient suspended ceilings will help improve the performance of the floor partition.
  • Ensure all support steels/timbers are carefully boxed out where they travel from flat to flat vertically and horizontally.
  • Use a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.

Due to the overwhelming variety of material designs and combinations due to varying constructions, it is impossible to cover all problems in a short article such as this; however in our experience if the acoustic design is taken into consideration from the offset of the project, then it usually results in a successful sound testing and compliance with Building Regulations Part E.

If you have a project that requires sound testing in London then contact us now, we can propose a sound testing schedule that should comply with Part E. Please contact us at: or call us at 07775623464

Acoustic Design Advice for my Sound Insulation Test

Acoustic Design Advice for my Sound Insulation Test

We at APT Sound Testing pride ourselves on offering a comprehensive acoustic design service to help you development attain compliance with Building Regulations Part E at the first attempt. If you send through the relevant drawings such as sections and floor plans during the design stages of the project, we can check the design is adequate and if there appears to be any junctions or details where ‘noise flanking’ may occur, we can then advise if any changes are required to lower the chance of sound test failures.


There are many factors to consider when considering good acoustic design, and they are usually split up into five key factors. If used together or in various combinations they will improve sound insulation properties over a wide range of frequencies. The main factors are:

  1. Mass
  2. Isolation
  3. Absorption
  4. Resilience
  5. Stiffness


Also, noise flanking transmission may in some cases be the dominant pathway between adjoining dwellings, especially in existing buildings where you are planning to convert offices/large houses into flats. Here are just a few of the potential noise flanking areas:

  1. Structural Steels
  2. Windows built very close to Internal partitions
  3. Inner leaf of the external wall
  4. External wall cavities
  5. External façade or outer leaf
  6. Roof structure

APT Sound Testing can advise on all types of acoustic design, whether it’s during the initial design of a new build project and/or undertaking sample sound testing and design during a refurbishment/renovation project. We also undertake UKAS accredited sound insulation testing providing a ‘one stop’ solution for all your acoustic requirements.

If you would like more information on our full range of our acoustic services please contact us now at or call Darren direct on 07775 623464.

How Is Sound Insulation Testing Carried Out?

How Is Sound Insulation Testing Carried Out?

For airborne wall and floor sound tests, two individual speaker positions are used for each source room; with a total of ten individual 1/3 octave band measurements recorded for both the source and receiver rooms. Measurements are then made to monitor the levels in the receiving room of the tested partition in question. This gives a basic level difference between source and receiver rooms.


This basic level difference is then ‘corrected’ to allow for the reverberation time (the time taken, in seconds, for a noise source to decay by 60 dB) and the existing levels of background noise monitored whilst in the receiving room.

All our tests are carried out in full accordance with BS EN ISO 140-1998 parts 4 (airborne sound testing) and 7 (impact sound testing), and the calculation of all single figure results are done so in accordance with BS EN ISO 717:1.

How do I know when my site is ready for testing?

Sound testing is typically conducted when a development nears completion, and once all internal and external doors and windows have been fitted, it is worth noting that no carpets should be installed prior to the sound testing.

To be able to conduct sound insulation testing we a constant supply of 240V power; we cannot use generator power. We also require a quiet site (a noisy site can make conducting the tests extremely difficult), so no drilling, jack hammers etc. should be used whilst the testing is taking place. We also require full access to all rooms to either side of the dividing partition so if it is a requirement to access a neighbour’s property, this must be arranged prior to the test date.

If you require a sound insulation test than contact us know, we will explain what the test entails and send you our informative checklist to help you prepare for the test. It is our mission to ensure our clients pass their testing at the first attempt. We pride ourselves on providing a ‘one stop acoustic solution’ for all your acoustic requirements.

If you would like more information in regards to our acoustic services, including acoustic design reviews, sound testing and noise surveys please contact us at: or call Darren on 07775623464 or visit our website at:




How are Plots Selected for Sound Testing?

How are plots selected for sound testing?

APT usually specifies the amount of sound insulation tests that are required. Firstly we look through the floor plans to work out a testing schedule taking into account the positioning of habitable rooms, the room and partitions sizes. We always tests through ‘habitable rooms’ partitions i.e. lounges & bedrooms wherever possible – as per the details shown below). We will also try and undertake testing across walls and floors in different areas of the building and through different partition types i.e. if one wall is made of masonry and the other met-sec partitioning.  Once we have specified the sound testing schedule, the client should show building control to seek their approval before the commencement of the sound testing.

Detail A – Sound Testing through Walls


Detail B – Sound Testing through Floors


What are the minimum requirements for separating party walls and floors?

The minimum requirements of ADE can depend on a variety of factors such as if the development is new build or refurbished, whether the development is intended to be a permanent dwelling, or classified as “rooms of residential purposes” (e.g. hotels, student accommodation, etc). A brief summary of the minimum requirements can be found below:


DnTw,w+Ctr dB

Impact Standard

L’nT,w dB


Purpose built dwellings

Walls at least 45 N/A
Floors and Stairs at least 45 up to 62

Dwelling formed by material change of use

Walls at least 43 N/A
Floors and Stairs at least 43 up to 64



DnTw,w+Ctr dB

Airborne standard

L’nT,w dB


Purpose-built rooms

Walls at least 43 N/A
Floors and Stairs at least 45 up to 62

Rooms formed by material change of use

Walls at least 43 N/A
Floor and Stairs at least 43 up to 64

If you have a project that requires acoustic design advice or sound insulation testing, then please contact us at: or phone me directly on 07775623464.