Sound insulation testing in Bristol

We provide UKAS-accredited sound insulation testing throughout Bristol and the surrounding towns of Patchway, Portishead and Yate providing our clients with reports for your building control officer with a quick and reliable turnaround to ensure compliance with Approved Document E.

Using our local knowledge and ability to respond quickly to your project requirements across Bristol and is of the highest quality and is also price competitive. We specialise in sound insulation testing and sound insulation design advice so give us a call to discuss your project or review our sound insulation design advice pages here to get started. Our specialist knowledge of Part E of the Building Regulations and the unique needs of our local clients means that we are one of Bristol’s most popular sound testing companies.

Bristol is a port city, with many people living in converted dwellings such as flats and apartments. In this overcrowded environment it is essential that noise transference between adjoining properties in kept to a minimum for the occupant’s wellbeing. One way of ascertaining that a building is in compliance with Building Regulations Part E for the prevention of noise transference, is to undertake Sound Insulation Testing in Bristol.

We have undertaken thousands of sound insulation tests throughout Bristol and the South East on many different types of project from simple flat conversions to large apartment blocks containing hundreds of flats. We also undertake Sound Testing where lease holder disputes has arisen, i.e. where the buildings lease stipulates that wooden floors should not be used instead of carpets and as a result of the change of floor finish the noise levels have increased – especially the impact noise. We can also undertake sample sound testing to highlight the existing noise levels so a targeted acoustic design can be undertaken.

We also undertake sound testing on office partitions for rooms classed as confidential – i.e. conference /meeting rooms. We usually undertake sample sound testing to establish the sound insulation performance of the existing partitions/doors etc. we then undertake a desktop review to offer advice on how clients can upgrade the partitions to their acoustic requirements. We then undertake final sound testing to ensure that the upgraded partitions meet client requirement.

Why do I need sound insulation testing in Bristol?

Sound insulation testing is required to make sure that a residential development can demonstrate acceptable levels of noise attenuation performance. Building Regulations Part E requires you undertake two different types of sound testing including airborne noise (i.e. sound/noise transmitted through the air, such as televisions and conversations between people) and impact noise (i.e. noise resulting from an impact on the floor surface, such as footsteps on the floor). By undertaking the two types of sound testing ensures the dwelling provides a reasonable resistance to the passage of sound.

Using our extensive knowledge regarding the way different materials and construction methods can influence the results of sound testing; we can offer easy to follow acoustic advice on the most awkward developments.

Does your Bristol development need sound testing?

Pre completion sound testing for Approved Document E has been a mandatory requirement since July 2003. All new build properties and conversions which were built after this date require 10% of each party wall/floor construction type to be tested. The sound test is to be carried out between pairs of rooms separated by party walls or floors, (however a greater percentage is required if you complying with Code for Sustainable Homes) in most cases the rooms to be sound tested will be the two main habitable rooms, which are usually living rooms and bedrooms.

The sound test procedure involves setting up a noise source in a room on one side of the party wall or floor and measuring the noise on both sides of the partition. At APT Sound Testing, acoustic testing is one of the most popular parts of our business; we also undertake air testing to your projects to comply with part L as well as part E. We can offer both Sound & Air Testing in Bristol – provided in one easy package; this helps reduce the cost and improve onsite co-ordination.

Pre-completion sound testing is generally carried out at the request of the Building Control Officer. The guidance contained within Approved Document E gives detailed recommendations for the partitions to be tested and for the number of sound tests that should be carried out. We recommend that the proposed sound testing is agreed in advance with the Building Control Officer (or person requiring the sound test

Our four step acoustic plan for your Bristol project

To try and help our clients achieve compliance with Approved Document E, we offer the following 4 step acoustic design advice package:

1. Site Survey Visits – to let us view the existing site construction. This allows us to check for potential problematic construction such as inclusion of lightweight blocks in the existing construction. It also lets us check that the installation teams are installing the acoustic materials as per manufacturer’s guidelines.

2. Sample Sound Testing – of the existing construction. This offers an accurate overview of the acoustic performance of the existing partitions which enables us to offer a targeted acoustic design using the sound insulation performance of the existing construction.

3. Acoustic Design Review – a full design review of the proposed developments party walls and floors. Site Survey Visits – to let us view the existing site construction. This allows us to check for potential problematic construction such as inclusion of lightweight blocks in the existing construction. It also lets us check that the installation teams are installing the acoustic materials as per manufacturer’s guidelines.

4. Pre-completion Sound Insulation Testing to satisfy Approved Document E.

Our acoustic design review service in Bristol

The first stage of our acoustic design services is to send through the design drawings – to include sections etc. we can review the design details to check that the construction details proposed are capable of passing the sound testing in-line with Part E of Building Regulations. This usually takes place straight after planning has been approved as increased cost savings can be realised at the earliest stage.

We can then evaluate the construction methods and materials specified to ensure that they are capable of meeting the acoustic requirements of Approved document E. The typical areas we check are:

a. The walls and floors design are acoustically robust, to comply with Building Regulations Part E.
b. There are no flanking points, where isolated partitions are wrongly mechanically fixed together to caused noise bridging.
c. The acoustic treatments for Soil Pipes, Stair Cases Steel Beams etc. to ensure they are acoustically fit for purpose, as these are some of the many areas that get missed.
d. The Lighting specification to, ensure they are acoustically complaint to the overall design i.e. down lighter design etc.
e. Acoustic floor treatments are compatible with the proposed floor finishes i.e. Carpets, Laminates, Floor Tiles and under floor heating systems.

If you are unsure of your buildings acoustic design and/or you require sound testing please don’t hesitate to contact us now. Using our many years of experience we can help you achieve compliance with Approved Document E.

Sound testing on Bristol office conversions

APT Sound Testing under-take hundreds of sound tests on building conversions throughout the capital every year. Many of the sound tests we undertake are typically the conversion of existing 3 storey houses in flats, i.e. from one house into 3 flats. However, we are now seeing an increase in the amount of existing office blocks being converted into dwellings.

When existing offices are converted into dwellings we usually undertake sample sound tests to check the existing sound levels prior to the commencement of construction works, once we have established the sound tests results we can then come up with a targeted acoustic design to comply with Approved Document E.

Historically, we have found that if the floor structure is usually made up of a 200mm concrete slab, which often means that the required airborne design doesn’t require much of an upgrade to meet the requirements of Part E; however, the impact results are often poor. This is because the airborne sound is broken down by the mass of the concrete slab, therefore sounds such as speech & TV etc. are minimised.

Unfortunately, impact sound results are often poor due to the lack of isolation within the slab, therefore the sound travels straight through the slab to the area below. This often manifests itself as loud footfall noise from above if remedial acoustic upgrades, such as the installation of acoustic mats are not undertaken during the construction phase of the development.

To help reduce potential control noise issues we can undertake a design review of the floors after sample sound testing to ensure both the airborne and impact sound tests pass Part E of Building Regulations. Once we have established the sound insulation performance of the existing structure we can forward an informed remedial treatment in compliance with Part E.

We offer simple solutions to reduce the noise levels and achieve compliance with Approved Document E. We supply simple easy to follow acoustic design reviews, utilising our extensive knowledge of different materials and construction methods

Reducing noise disturbance my Bristol property

We have seen a large increase in the amount of clients contacting us because they want to improve the sound insulation in their existing dwelling/s.

In the last 15 years, domestic noise complaints have increased five-fold. This noise can result in frustration, anger and sleep disturbance. It can also act as a catalyst for other effects on health in relation to sound insulation. In addition, the noise generated within dwellings and from occupant life styles varies significantly between households.

Firstly, growth in the use of electrical appliances, such as speaker systems within the home and rapid technological advancements in entertainment systems have increased the levels of noise within today’s home.

Second, changes in work patterns and the ways in which homes are used may result in diverse neighbour lifestyles, i.e. many people now work night shifts etc.

Third, the fast pace of modern living and varied employment patterns not only limit the quantity of time spent within the home but also place more importance on this greatly restricted quality time. Thus the disruption to occupants and annoyance caused by sound from neighbouring dwellings plays a massive role in a person’s quality of life.

There are a variety of reasons why sound insulation may need to be improved. Some of the typical reasons given by occupants, property managers and developers are:

a. The original existing construction was never suitable to meet the insulation standards required of a separating wall or floor structure – in-line with Part E of Building Regulations.
b. The existing wall or floor components have deteriorated over time and are in need of replacement this may be because the wrong fixings have been used on the existing floors bridging the acoustic elements and have damaged original components.
c. Poor workmanship at the time of construction has led to poor sound insulation and noise flanking.
d. The upgrading of the existing windows to double and/or triple glazing has reduced external or background noise through the building façade, thus making it easier to hear neighbour noise through separating walls and floors.
e. A change in material of wall or floor finishes (e.g. carpet to laminate flooring), has increased the level of noise transmitted to the dwelling below – this is one of the most common reasons an increase in noise. Also cut outs in the existing wall to flush fit LCD TV’s is another popular reason for noise bridging through walls.
f. A building is converted and requires separating wall and floor sound insulation performance levels in compliance with Building Standard, which is often difficult to achieve as the building was not purpose built to be separate dwellings.

The sound insulation levels achieved by a separating wall or floor will be influenced by the following:

a. The original acoustic design
b. The materials and fixings used
c. Structural junctions with other walls and floors
d. The quality of workmanship throughout the construction phase of the acoustic elements
e. Previous work or alterations on the existing structure
f. Changes to components as a result of damage or wear and tear
g. Each type of wall and/or floor was sound tested during the precompletion phase – each different type should be tested but often isn’t.

In addition to the above the materials used and interior architecture have varied between periods of construction and architectural styles. The sound insulation performance of identical dwelling types may be similar, but often are different due to the influences outlined above.

We can visit site and undertake sound insulation testing through your property to establish the current noise levels. Once the noise levels have been established we can advise on acoustic upgrades to help you improve the sound insulation levels.

Ceiling treatments to improve sound testing in Bristol

When clients have a problem with sound transmissions through floors we generally advise the installation of secondary ceilings with a minimum of 100mm between the existing and new constructions. If the works are being undertaken to a Victorian house the ceilings are usually a minimum clearance of 2.8m which easily allows for the overall dimension of the 230mm for the remedial ceiling treatment. Generally the greater the ceiling void depth aligned with less direct connection between the new and existing ceilings the better the improvement in your sound insulation test results.

In newer buildings the ceilings to floor dimension may only be 2.5m. In these cases keeping a more shallow remedial treatment will be a priority. To get over this a fixing mechanism may compensate for the limited depth. By using composite supports such as timber battens and metal resilient bars it can improve sound insulation with ceiling voids depths of 70mm. due to the direct fixing details this acoustic treatment will not offer robust sound insulation properties of the independent ceiling treatment.

If impact noise is one of the main problems with your property there are some easy treatments to improve this. If an installing absorption layers within the ceiling void such as AW sound insulation can also increase sound insulation for airborne noise and impact noise helping you to pass the Part E sound testing. However, care should be taken the correct installation of electrical cables to prevent overheating. In all instances the installation must comply with BS 7671.

You must also consider the additional weight of fixings, boards and insulation will increase loading on the original structure. If you are removing lathe and plaster and installing a resilient layer and a single layer of sound board then this shouldn’t be a problem. However if a large amount of upgrades are required then specialist advice from structural engineers should be sought to check if the existing structure can accommodate the additional loads.

In our experience one easy way to provide adequate isolation is the through the installation of metal resilient bars. The resilient bars are typically 11–16mm thick and vary in design and resilience. Resilient bars should never be mounted directly to the underside of an existing ceiling as this creates full contact between the ceiling and the resilient bar for its full length which may result in a sound test failure.

When your existing structure has both concrete and timber floors, where the existing ceiling is not being removed and resilient bars are being used, it is always preferable to install a 50 x 50mm timber batten and then mount the resilient bar perpendicular to the brander, i.e. the resilient bars should run across the batten’s to allow for the minimal contact.

If you are utilising an existing concrete floor and you are removing the existing ceiling the timber battens should be used prior to installing the resilient bars. In the case of joist floors the resilient bars may be directly connected to the joists provided they are perpendicular (at right angles) to the direction of the joist.

Using absorption layers, such as mineral wool within the ceiling voids can improve sound insulation for speech, TV and general living noise. However, the primary pathways for sound may not always be through the floor or ceiling cavities but via the floor joists and perimeter walls. In such cases, placing quilts or absorbent layers within the floor voids may only a limited effect. Mounting additional ceiling boards directly to the existing ceiling, where the ceiling is directly fixed to joists, will marginally increase the mass and ceiling however it doesn’t always make much difference to the overall sound insulation performance. In this instance you may also need to install a resilient layer to the walls or build an independent wall in front of the existing walls to pass the Part E sound testing.

Another common source of complaint of poor noise levels in flats can be related to drainage runs, drainage stacks or soil and vent pipes (SVPs). The most common method to reduce noise transmission from services is to enclose pipe runs or stacks in a generic lining or proprietary lining system.

In our experience generic solutions are normally less expensive than proprietary systems but may be more time consuming to fit. In both cases the wrapped insulation should completely surround the pipe and the boxing and gypsum board should not come into direct contact with the pipe or pipe fixings. It’s often prudent to use two layers of lapped gypsum board for the outer lining.

Where there are horizontal pipe runs through separating floors either in the ceiling void or in floor cavities between timber joists these may require to be wrapped and boxed with two layers of lapped gypsum-based board. In some cases it is difficult to box these services and so heavy proprietary pipe wrap systems involving multi-layered materials may be required.

We believe in working with our clients whether they are existing home owners needing minor acoustic upgrades or large developers requiring a more expansive service to achieve sound testing compliance. We believe that by being involved at the beginning of a project we can often save our clients expensive and difficult remedial works at the completion stage of a project.

Remedial wall treatment in Bristol

If you have failed you party wall sound insulation test, remedial treatments can be applied to party walls between residential spaces in order to improve airborne sound insulation and achieve a pass. These are many treatments that can be applied to the wall which include cavity infill insulation, wet and dry lining as well as independent linings.

On existing masonry and blockwork walls may present poor airborne sound insulation performance due to various anomalies in the dry lining finishes (open mortar joints, uneven blockwork façade etc.).

The application of a parge coat

The application of a parge, or render coating to the wall’s face before dry-lining contributes significantly towards a successful sound insulation test. This is due to the fact that this procedure seals any open joints and increases the mass of the wall. The wet treatments are usually composed of a cement-sand mix. Gypsum-based coatings are also available off the shelf. A parge coated wall is often finished with a plasterboard layer on dabs. The parge coat should be scratch finished or applied unevenly in order to create a better bonding surface for the drylining dab. The parge coat should never be stronger than the blockwork on which it is applied, since mortar joints may crack during the drying.

Mineral wool boards

Boards with mineral wool backing layer Walls can also be lined with boards which employ a compressed mineral wool backing layer. These are best used with 8mm render or parge coat when combined with a blockwork wall and vary in thickness (usually between 32mm and 50mm). This type of treatment performs well when installed on the residential side of a separating wall to a communal area (hallway, corridor, stairwell).

Composite boards

Composite boards are usually constructed using a mixture of acoustic grade plasterboard along with an acoustic resilient layer. They can usually be applied to either masonry or stud walls and in some instances reduce flanking noise up and down walls. This type of construction is often favoured where a small improvement is required to the walls and/or the client has minimal site tolerance

Independent wall treatments

Independent wall constructions provide a combination of isolation, resilience and absorption, offering an excellent approach to improving the sound insulation of a wall. The independent lining is usually a metal or timber frame set off from the existing wall. The size of the metal or timber studs depends on a number of factors such as floor to ceiling height and structural loads on the wall.

The independent wall must not come in direct contact with the existing wall. This is why a minimum separation of 20mm is always advised. However, it is always connected to the floor and ceiling by a set of channels. In order to further improve the sound insulation performance, a layer of mineral wool (minimum 25mm) should be installed between the frames, while the finish should incorporate one or two layers of dense plasterboard. In terms of sound insulation improvements this is usually the best option.

Sound intrusion through windows on your Bristol property

Sound intrusion though windows can also be a source of great annoyance if the sound is excessive. Window glass is one of the least efficient sound-blocking substances in any home. A single pane of glass will almost allow as much noise to come through as if there wasn’t any glass there in the first place. Since windows are a feature on every type of home, noise intrusion through windows is always taken as a given.

To reduce the amount of sound/noise that comes through windows, you must improve the sound properties of the window itself. This can be done in four ways:-

a. Add mass to the glass – make it thicker
b. Add a larger gap between the window panes – double and/or triple glazed
c. Use a laminate soundproof glass to increase the sound insulation rating of a window
d. Add heavy duty curtains or shutters to windows.

Double glazing can improve sound insulation, especially if it’s replacing old single glazed windows. Generally a larger the gap between the panes will result in better sound insulation. This can be further enhanced where the glass is a different thickness; i.e. 6mm glass one side and 4mm the other. This will usually improve the sound test results over a normal sealed unit, because the different thickness of glass changes the sound wave as it travels through the unit.

The second option is to use 6.4mm laminate glass to the outside of your glazing to offer additional sound proofing. This is also much more secure from a security viewpoint as laminated glass is much more difficult to penetrate as it houses 0.4mm perspex between the two 3.0mm panes of glass. This type of glass is often used in car windscreens.

It is also worth noting that the use of trickle ventilators within a window can greatly reduce the acoustic performance of new windows. When noise is a major problem – such as windows being adjacent to a busy road) acoustic ventilators may be necessary, however, the downside of this is they are often large and unsightly.

If you add an extra pane of glass with triple glazing, it may only provide a small increase in sound insulation, if all three panes are of the same thickness. Specifying one different pane thickness will increase sound insulation.  One of the best ways to improve sound insulation is to introduce secondary glazing as the gap between both panels is far greater than conventional double glazing. Many houses around airports are fitted with secondary glazing to help with the noise reduction of air traffic noise.

Also, if you live next to a main road with high amounts of traffic noise, secondary glazing is a great way to reduce further noise as you can also benefit from the different thickness of glass from that of the primary window. The optimum gap to reduce heat loss and keeping external noise to a minimum is between 100mm-150mm between the secondary glazed unit and your existing window (glass to glass).

Changing the thickness of the glass between your existing window and your new secondary glazing will also improve noise by changing the frequencies of the sound wave length i.e. if the existing window glass is 4mm – install a secondary glass pane of 6mm.

One of the best ways to reduce the sound through your windows would be to introduce a combination of the above by replacing both the outer window with good quality, tight fitting double or triple glazing and then add secondary glazing as well. This method is obviously more costly but will give you the best results acoustically.
We offer simple solutions to reduce the noise levels and achieve compliance with Approved Document E. We supply simple easy to follow acoustic design reviews, utilising our extensive knowledge of different materials and construction methods

Designing your building to pass Part E sound testing in Bristol.

We often get asked what architectural features or plan arrangements can reduce the level of sound insulation or introduce additional sources that may cause us to fail our sound testing. Here is a quick list of the most common problems:

a. Internal stairs directly beside a separating wall – this can lead to footsteps being heard inside the adjacent dwelling, especially in bedrooms.

b. Using lightweight blocks on flats – lightweight blocks are often used in the construction of internal walls despite the block manufacturer’s warnings that they should not be used for the inner envelope or dividing wall construction. The walls are so lightweight they vibrate (almost like a snare drum) so sound can travel up or across the partition.

c. Chimney stacks, flues and fireplaces built within a separating wall – this can lead to sound traveling up the flue and being heard in flats above and/or below.

d. Recessed cupboards (presses) within a separating wall – this usually means that the width of the sound insulation is compromised which directly leads to a reduction in sound insulation levels.

e. A flat spanning over several flats below, for instance a penthouse;

f. Communal stairs beside a separating wall – as this is a heavy trafficked area it can lead to footsteps being heard inside the adjacent dwelling, especially in bedrooms.

g. Communal vertical soil vent pipes and horizontal service pipes within a separating floor – if the services are not properly boxed out this can lead to general noise going straight through the floor as well as the noise of flushing water as it runs down the SVP pipes etc.

h. Lifts beside separating walls – this is often a bad scenario due to the higher start up current that’s needed to start a lift, this can cause a loud whine when the lift first starts and if there is insufficient sound insulation within the lift wall this will usually be heard by the adjacent resident/s.

i. Water pumps used to raise water pressure – this can be problematic especially where a bedroom is located on the opposite side of the partition.

j. Chimney stacks, flues and fireplaces built within a separating wall – this is often a major cause of noise problems as they are often built quite close to each other thus reducing the mass of the separating wall/partition.

k. Recessed cupboards (presses) within a separating wall – again this reduces the sound insulation levels as it reduces the mass of the wall partition.

It is worth noting that with careful consideration during the design phase most potential sound transference problems can be negated.

It is worth noting that general exposure to noise from adjacent dwellings may act as a catalyst affecting the occupant’s health and well-being. Noise that is unavoidable, unimportant or emotive is often the most annoying. Disrupted sleep and listening to television/radio are the most common noise-disrupted activities. Noise transmission between dwellings causes increased tension between neighbours and leads to disputes, which may result in physical assaults.

If you are unsure of your buildings acoustic design and/or you require sound testing please don’t hesitate to contact us now. Using our many years of experience we can help you achieve compliance with Approved Document E.

Quantifying sound testing

We often get asked ‘what are the parameters behind sound testing under Approved Document E’. To try and clarify this in more detail we have written a brief explanation.

What is sound or noise?

Noise is often defined as unwanted sound. Sound is defined as any pressure variation heard by the human ear. The sound pressure level (SPL) is a measure of the air vibrations that make up sound. Because the human ear is sensitive to a wide range of pressure levels, the SPL is measured on a logarithmic scale with units of decibels (dB).

How do we humans perceive noise or sound?

Healthy human ears perceive pressure variations over a wide range of frequencies — from low as low as 20 Hz to frequencies as high as 20,000 Hz. The human ear’s range starts at the threshold of hearing (0 dB) and ends at the threshold of pain (around 140dB) which would be the same as standing next to a large jet engine.

The human ear is less sensitive to sounds in the low frequencies compared to the higher frequencies. For example, a 50 Hz tone must be at a level of 85 dB in order to be perceived by the human ear as being the same loudness as the higher frequency 1000-Hz tone at a level of 70dB.

How do you quantify sound?

As mentioned above, sound levels are usually measured and expressed in decibels (dB). Most environmental noise does not consist of a single frequency, but rather a broad band of frequencies differing in sound level. The intensities of each frequency add to generate sound. The method commonly used to quantify environmental sounds involves evaluating all of the frequencies of a sound according to a weighting system which reflects that human hearing is less sensitive at low frequencies and extremely high frequencies than at the mid-range frequencies. This is called “A” weighting, and the decibel level measured is called the A-weighted sound level (dBA).

Quantifying sound testing failures

As a rule of thumb, a doubling in the loudness of the sound occurs with every increase of 10 dB in sound pressure. In other words, for most individuals a 60 dBA noise would sound twice as loud as a 50 dBA noise.

If a sound testing fails, the client often asks by how much. When we confirm it has failed by 5dB they usually say ‘if that’s the case I only need to improve the partition by 10%’, unfortunately that isn’t the case – the partition has actually failed by 50% subsequently the partition will need major upgrades to pass the sound testing under Part E of Building Regulations.

We can advise on all types of acoustic design, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We have the technical experience to help identify and rectify your soundproofing or noise control problem.

How many sound tests does my Bristol project require?

Approved Document E for England and Wales, 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 and the amount of different types of wall or floor constructions. On a typical small to medium development consisting of up to 10 dwellings with the same partition construction should require 1 x 6 pack, which consists of 2 airborne wall tests, 2 airborne floor tests and 2 impact floor tests.

In most cases the rooms to be sound tested will be the two main habitable rooms which would be living rooms and bedrooms. The sound test procedure involves setting up a noise source in a room on one side of the party wall or floor and measuring the noise on both sides of the partition.

If you are unsure of the amount of tests required on your project, the guidance contained within Approved Document E can be very helpful as it gives detailed recommendations for the partitions to be tested and for the number of sound tests that should be carried out. We recommend that the proposed sound testing is agreed in advance with the Building Control Officer and/or persons requiring the sound test.

It is worth noting that when we carry out a quotation for clients it usually contains a full schedule of sound tests to comply with Building Regulation Part E; you can then table the schedule to your approved inspector to check that its acceptable prior to the testing. We also send out an informative checklist to help you prepare for your sound testing. Our sound test schedule will usually look similar to this:

Airborne Wall

• Plot 1 Lounge to Plot 2 Lounge
• Plot 1 Bedroom to Plot 2 Bedroom

Airborne Floor

• Plot 1 Lounge to Plot 3 Lounge
• Plot 1 Bedroom to Plot 3 Bedroom

Impact Floor

• Plot 3 Lounge to Plot 1 Lounge
• Plot 3 Bedroom to Plot 1 Bedroom

If you are unsure how many sound tests you require on your project, please don’t hesitate to contact us now. Using our extensive knowledge of different types of developments we can forward a concise testing schedule in compliance with Building Regulation Part E.

Preparing your site for sound testing in Bristol

Our clients require accurate sound test results; however to allow us to achieve this certain guidelines must be followed by the client site team and operatives, such as keeping site noise levels to be kept to a minimum etc. Any site operatives working in the testing area will have to leave temporarily and any noisy works in the vicinity of the test areas such as groundworks, drilling and banging will need to be suspended.

We always provide a full sound testing checklist within our quotation which identifies what actions need to be undertaken to prepare for the sound insulation testing.

The preparation of the buildings/dwelling is very important, as they can influence the results of the test. The following stages for sound testing will help preparation and also assess the point at which completed buildings can be tested. Generally before the test the parts of the building/rooms either side of the separating wall or separating floor should be complete. Particular attention should be paid to the following:

1. All separating floors and walls and all flanking walls and floors should be complete.
2. All wall and floor junctions should be complete – to include flanking strips etc.
3. All wall finishes should be complete, this should include skirting’s being in place. This does not include decorative finishes such as paint.
4. Floors must be bare and no carpets should be laid – where a concrete floor with bonded resilient cover is to be fitted with wood based flooring. In this case, the test sample resilient floor cover should be tested with a wood based floor covering laid over the test sample area.
5. Windows should be installed with all glass fitted.
6. Trickle vents should be in place and closed.
7. All doors should be fully fitted and closed. This includes internal doors and external doors fully fitted with doors seals.
8. Services should be complete and any voids around ducts finished.
9. Electrical sockets should be fitted.
10. A 240V electricity supply should be available to all the test plots.
11. There should be no noise during the test other than from the testing equipment.
12. The test plots and adjacent areas within the building should be quiet for the duration of the test.
13. No work should be carried out or noise made in the building at the time of the test.
14. Site workers should not enter the building or be in the parts of the building undergoing a test.

What’s the duration of the sound testing on my Bristol Project?

The duration of the sound testing depends on a number of factors such as the amount of tests required on the project. For instance sound testing on a pair of semi-detached houses, would require two airborne walls tests, which would take one to two hours. A standard six pack of tests for a block of up to 10 flats would usually require six sound tests, which would consist of two airborne walls, two airborne floor and two impact tests – this would take two to three hours. For every 6 tests thereafter will be another 2-3 hours would need to be applied. If the site conditions are agreeable we can undertake up to 18 sound tests in one day; however, to allow this to happen we will require full free uninterrupted access to the units/rooms in all test areas.

If you need to more information in regards to our precompletion sound testing service then please contact us now. We supply a simple four step solution for all your acoustic design and preconstruction sound testing for your Bristol projects.

Why have I failed my sound insulation test in Bristol?

If our clients fail their sound testing this is usually the first question they ask. One of the main reasons for acoustic partitions failing an Approved Document E sound test is often down to poor isolation of material/s, which can lead to excessive noise flanking.

Noise Flanking is a term used by acoustic engineers to describe where sound passes through an acoustic partition due to the abutment of materials. The noise simply hits the one side of the wall and then travels through the construction via a noise bridge. This can be areas such as the incorrect use of masonry wall ties i.e. solid fishtail ties, used in place of specified acoustic wall ties.

Unwanted noise travelling along flanking paths can make the building structure vibrate, which can cause sound to radiate into your room. One simple cost effective solution is to build another wall or ceiling in front of the original, to offer extra isolation. For this upgrade to work you need to make sure that the independent wall or ceiling is not directly connected to the existing failed partition; so it provides isolation between materials.

Another reason for excessive noise flanking is often down to the use of down to the use of lightweight blocks in the construction of the building envelope. Due to the lightweight mas of the inner wall it allows sound to transmit from dwelling to another, both vertically and horizontally. If a building has failed its sound testing, it is essential to establish if the problem is due to direct transmission, flanking transmission or a combination of both so that the most cost and time effective remedial treatment can be designed and applied to the failed partitions.

One of the easiest ways to reduce the chance of sound testing failures due to excessive noise flanking transmission is through a careful consideration to the acoustic design at the start of the project. Unfortunately, by simply specifying high performance wall and floor partitions, it is no guarantee to adequate sound isolation and successful sound testing.

We offer preconstruction design advice to help you achieve successful sound testing in-line with Building Regulations Part E. We also offer onsite inspection services to ensure that the sound insulation elements are being installed as per manufactures guild-lines, as it’s no use having good acoustic design if it not being installed properly on site.

During early design and construction process, we visit site to conduct a comprehensive acoustic design survey and review, we also take this opportunity to meet; where possible, the site/project manager, architects etc. The first stage of the acoustic design is to send through the design drawings – to include sections etc. We then review the design to check that the construction details proposed are capable of passing the sound tests. This usually takes place straight after planning has been approved as increased cost savings can be realised at the earliest stage, we will evaluate the construction methods and materials specified to ensure that they are capable of meeting the acoustic requirements of Approved document E. The typical areas we check are:

a. There are no flanking points, where isolated partitions are wrongly mechanically fixed together to caused noise bridging.
b. The walls and floors design are acoustically robust, to comply with Building Regulations Part E.
c. The acoustic treatments for Soil Pipes, Stair Cases Steel Beams etc. to ensure they are acoustically fit for purpose, as these are some of the areas that get usually missed.
d. Acoustic floor treatments are compatible with the proposed floor finishes i.e. Carpets, Laminates, Floor Tiles and under floor heating systems.

We also provide on-going design support service, so you will have direct contact with the allocated acoustician from the start of the process through to the successful completion of the project. One of the most important services is the going site survey visits which allow our clients 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.

If you require sound testing and don’t know how to proceed with the acoustic design and/or sound insulation testing your project, please don’t hesitate to contact us. Using our many years of experience we can help you achieve compliance with Approved Document E.

What is airborne sound testing in Bristol?

One explanation of airborne sound is as follows; when a sound wave is incidental upon a partition between two dwellings, part of it is reflected and part of it is transmitted through the wall of floor partition.

For single leaf structures, such as dense masonry brickwork, the transmission follows the mass law, i.e. the more massive the structure, the smaller the quantity of transmitted sound.

For lightweight structures consisting of multiple layers, such as a twin met-sec gypsum wall, the spring-mass law is applicable. If highly absorbent material such as acoustic insulation is used within the construction of a double leaf wall, the sound insulation improves. The wider the cavity, the greater the benefit from stone wool will be. If a cavity has been filled with acoustic wool your sound test result should typically improve by 5 – 10 dB.

Airborne sound testing is undertaken to walls & floors. Firstly a controlled noise is generated by an amplifier and loudspeaker across a broad range of frequencies. The generated noise is very loud and is often in excess of 100dB. Initial measurements are taken using a class 1 sound level meter within the ‘source room’ followed by further measurements in the ‘receiver room’ on the other side of the wall or floor under investigation. The source room speaker position is then changed and the measurements repeated either side of the partition under test.

Thereafter background noise measurements are made using a class 1 sound level meter in the receiving room and are used to apply appropriate corrections for external sound such as traffic noise. Similarly the reverberation time (the time taken for sound to decay by 60dB) is measured within the receiving room using the sound source and a sound level meter to determine the corrections that must be applied to account for the characteristics and absorptiveness of the room.

The difference in the two airborne noise levels (for walls and floors), corrected for background and reverberation characteristics determines the airborne sound insulation performance of the wall, or floor. A greater airborne noise difference between the source room and the receiver room determines a higher airborne sound insulation performance.

If you need to more information in regards to our airborne sound testing service then please contact us now. We supply a simple precompletion testing solution for all your acoustic requirements.

What is impact sound testing in Bristol?

An impact sound source sets up vibrations directly in the element it strikes whereas 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 partitions.

The impact vibrations spread out over the whole partition/s and into elements connected to it, such as internal walls and floors as well as the inner leaves of external walls. The vibrations in the wall/floor elements force the air beside them to vibrate and it is these new airborne vibrations that are heard.

In most cases a floor depends on its mass to reduce airborne sound and on the soft covering to reduce impact sound at source – this often confuses people.

Using an acoustic membrane such as a Regupol multi will largely isolates the walking surface from the base and should improve the impact and to a lesser extend the airborne sound insulation results.

Impact sound transmission testing is undertaken to floors only. This actual methodology behind the test is different to airborne as a calibrated Norsonic ‘tapping machine’ is used for the test, which comprises of five ‘hammers’ driven up and down by a cam and electric motor is used to “tap” the floor surface by applying a known force on the floor structure. The machine is placed in several pre-determined positions. The resulting noise is measured in the dwelling below, using a sound level meter.

Thereafter, background noise measurements are made using a class 1 sound level meter in the receiving room and are used to apply appropriate corrections for external sound such as traffic noise. Similarly the reverberation time (the time taken for sound to decay by 60dB) is measured within the receiving room using the sound source and a sound level meter to determine the corrections that must be applied to allow for the characteristics and absorptiveness of the room.

The measured noise levels in the receiving room are corrected for background and reverberation characteristics determine the impact sound insulation performance of the floor. For the impact noise the lower the measured level, the better the performance as less sound is being transmitted into the dwelling below.

If you need to more information in regards to our impact sound testing service then please contact us now. We supply a simple precompletion testing solution for all your acoustic requirements.

What is noise flanking in Bristol?

Noise flanking (or flanking sound) is sound that transmits between spaces indirectly, i.e. it travels around the edge of materials rather than passing directly through the main separating wall and/or floor partitions.

Unfortunately this may result in a sound test failure even if the main separating element itself is robust and provides good acoustic insulation. Noise flanking can result from both impact sounds and airborne sounds. Any building element that penetrates or circumnavigates a separating element can result in flanking.

To help consultants and contractors we have comprised a list of the most common noise flanking paths:

a. Dividing 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)

b. Dividing Ceiling Partitions – Above and Through the Ceiling Space (where an adequate acoustic break has not been carried on through the ceiling void)

c. Shared Structural Building Components – Floor Boards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.

d. 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)

e. 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 areas.

f. Through Windows (if they are no double glazed or have secondary glazing as a minimum)

g. Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)

h. Ductwork and pipework – this often runs through the acoustic partition from dwelling to dwelling, especially in new apartment construction.

i. Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic.

j. Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)

k. Poor workmanship – can cause noise flanking as operatives are often in a rush to construct the acoustic partitions etc. which often means the incorrect fixings are during the construction process.

Within building regulations Approved Document E: Resistance to the passage of sound, it clearly 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’.

Noise flanking should be considered during the design stage of new projects and good acoustic detailing should eliminate or minimise the inadvertent downgrading of sound insulation. in many cases, junctions between elements can offer a potential flanking route if they are not carefully detailed and constructed. Good briefing and ongoing supervision during the construction phase can help to ensure that the quality of workmanship remains high so that details are constructed as designed.

If you need to more information in regards to potential noise flanking issues on your project then please contact us now. We supply a simple precompletion testing solution for all your acoustic requirements.

Sound intrusion through windows on your Bristol property

Sound intrusion though windows can also be a source of great annoyance if the sound is excessive. Window glass is one of the least efficient sound-blocking substances in any home. A single pane of glass will almost allow as much noise to come through as if there wasn’t any glass there in the first place. Since windows are a feature on every type of home, noise intrusion through windows is always taken as a given.

To reduce the amount of sound/noise that comes through windows, you must improve the sound properties of the window itself. This can be done in four ways:-

a. Add mass to the glass – make it thicker
b. Add a larger gap between the window panes – double and/or triple glazed
c. Use a laminate soundproof glass to increase the sound insulation rating of a window
d. Add heavy duty curtains or shutters to windows

Double glazing can improve sound insulation, especially if it’s replacing old single glazed windows. Generally a larger the gap between the panes will result in better sound insulation. This can be further enhanced where the glass is a different thickness; i.e. 6mm glass one side and 4mm the other. This will usually improve the sound test results over a normal sealed unit, because the different thickness of glass changes the sound wave as it travels through the unit.

The second option is to use 6.4mm laminate glass to the outside of your glazing to offer additional sound proofing. This is also much more secure from a security viewpoint as laminated glass is much more difficult to penetrate as it houses 0.4mm perspex between the two 3.0mm panes of glass. This type of glass is often used in car windscreens.

It is also worth noting that the use of trickle ventilators within a window can greatly reduce the acoustic performance of new windows. When noise is a major problem – such as windows being adjacent to a busy road) acoustic ventilators may be necessary, however, the downside of this is they are often large and unsightly

If you add an extra pane of glass with triple glazing, it may only provide a small increase in sound insulation, if all three panes are of the same thickness. Specifying one different pane thickness will increase sound insulation.  One of the best ways to improve sound insulation is to introduce secondary glazing as the gap between both panels is far greater than conventional double glazing. Many houses around airports are fitted with secondary glazing to help with the noise reduction of air traffic noise.

Also, if you live next to a main road with high amounts of traffic noise, secondary glazing is a great way to reduce further noise as you can also benefit from the different thickness of glass from that of the primary window. The optimum gap to reduce heat loss and keeping external noise to a minimum is between 100mm-150mm between the secondary glazed unit and your existing window (glass to glass).

Changing the thickness of the glass between your existing window and your new secondary glazing will also improve noise by changing the frequencies of the sound wave length i.e. if the existing window glass is 4mm – install a secondary glass pane of 6mm.

One of the best ways to reduce the sound through your windows would be to introduce a combination of the above by replacing both the outer window with good quality, tight fitting double or triple glazing and then add secondary glazing as well. This method is obviously more costly but will give you the best results acoustically.

We offer simple solutions to reduce the noise levels and achieve compliance with Approved Document E. We supply simple easy to follow acoustic design reviews, utilising our extensive knowledge of different materials and construction methods

The difference between Rw (Laboratory) and DnTw? (Field) Sound Testing

One of the most common points of confusion in sound testing terminology is the difference between Rw and DnT,w. getting these two types of sound testing mixed up can lead to under sound test failure performance or overspending on an over specified acoustic solutions. Here is a quick explanation for both.

The term DnT,w is used in reference to on-site sound insulation and it describes the in-situ or onsite airborne sound insulating power of a building element. Because it’s on-site, DnT,w accounts for all physical channels of sound transmission, including through a partition separating two spaces and any flanking paths around it, for example, ventilation, external walls and ceiling voids.

The term Rw, is the weighted sound reduction index in dB (decibels) and it describes the airborne sound insulating power of a building element. It is a laboratory-measured value as defined in ISO717 Part 1. It can apply to walls, ceiling/ floors, ceiling/roofs, doors, or windows. The higher the number, the greater the sound insulating power of the building element. It is measured over the frequency range 100 to 3150Hz Walls carrying this kind of value have been tested in isolation, without the on-site channels of sound transmission mentioned above which usually has a negative impact on the sound test results.

Using both DnT,w and Rw measurements, provides construction designers and contractors a more accurate idea of how different walls or floors will perform. The same wall measured in laboratory conditions will produce the same result every time, but when measured on-site, results will vary from one space to another. When you convert laboratory-rated performance (Rw) to on-site (DnT,w) testing, there is many more factors to take into account, including the reverberation time and volume of the ‘receiving’ room, the size of the separating partition and the potential surrounding transmission on-site from the aforementioned channels. This last factor, which is often the most important, is closely aligned with the construction quality of the site, and attention to construction detailing.

Unfortunately, because of the DnT,w’s potential to vary between partitions, there’s no simple formula for conversion. There are a number of assumptions that can be made and generally the difference between Rw and DnT,w can range between 5 – 10 dB. We have found that with masonry or concrete constructed party walls and floors that the difference will be closer to 3-5dB, however with lightweight timber and steel constructions the difference will be closer to 8-10dB.

Ensuring you consult us at the beginning of your project can save you costly errors in specifying the incorrect partition walls and floors for your project. APT Sound Testing can run through a large range of wall and floor acoustic upgrades achieve Part E of the building regulations.

Frequently asked questions for Sound Testing in Bristol

1. Why am I required to undertake sound insulation testing?

Sound insulation and speech privacy are critical for a variety of reasons. Inadequate sound insulation can be extremely distressing to those affected by it and may lead no major noise disputes and legal actions. For example, in an apartment block, your upstairs neighbour may like playing loud music. However, the downstairs occupant may be working nights and sleeping throughout the day, thus any inadequate sound insulation between these two flats would cause great disturbance and distress to the downstairs occupants.

2. What is pre-completion sound insulation testing?

Pre-completion sound testing is a building regulation requirement for all new build and dwellings formed by ‘material change of use”, i.e. conversion projects. It has been a requirement that you undertake sound testing on dwellings since 2003. Sound testing should be undertaken to 10% of properties in each development to ensure that the separating walls & floors between habitable rooms of neighbouring properties meet the minimum requirements as defined by Approved Document E, commonly referred to as Approved Document E; for instance:

• For a pair of semi-detached Houses – a set of tests would usually comprise two airborne sound insulation tests of a separating wall.
• For Flats (up to 10 units) – a six pack would normally be required, this comprises of: two airborne wall tests, two airborne floor tests and two impact floor sound tests. The easiest way to work out the number of tests required is to multiply 1 x 6 packs for every 10 flats, i.e. if you have 22 flats you will require 3 x 6 packs which equals 18 sound tests in total.
• For Rooms for Residential Purposes (up to 10 rooms) (student accommodation, hotel rooms, care homes etc.) – a set of tests would usually comprise: one airborne sound insulation tests of a separating wall; one airborne sound insulation test of a separating floor; one impact sound transmission test of a separating floor.

3.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. 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.

4. What are the minimum acoustic 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 – all results should be shown as: DnTw,w+Ctr dB & L’nT,w dB

• Purpose Build Dwellings – Airborne 45dB & Impact 62dB
• Conversion Projects – Airborne 43dB & Impact 64dB
• Purpose Built Rooms for Residential Purposes – Airborne wall 43dB, Airborne floor 45dB & Impact 62dB
• Conversion Projects Rooms for Residential Purposes – Airborne 43dB & Impact 64dB

5. 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.

6. 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.

7. Do you offer acoustic advice to help me pass my sound insulation test?

Yes, we can offer an acoustic design service to help you design your buildings partitions to pass Part E sound testing. 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..

8. Why am I required to undertake sound insulation testing in Bristol?

Sound insulation and speech privacy are critical for a variety of reasons. Inadequate sound insulation can be extremely distressing to those affected by it and may lead no major noise disputes and legal actions. For example, in an apartment block, your upstairs neighbour may like playing loud music. However, the downstairs occupant may be working nights and sleeping throughout the day, thus any inadequate sound insulation between these two flats would cause great disturbance and distress to the downstairs occupants.

If you need to more information in regards to our precompletion sound testing service then please contact us now. We supply a simple four step solution for all your acoustic design and preconstruction sound testing.

Acoustic Terminology Associated with Approved Document E.

We often find that confusion can arise from the large amount of ‘acoustic terms’ used in conjunction with acoustic design and sound insulation testing. To help with this we have made a list of the following terms for clarity:

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

2. Absorbent Material – This is a material that absorbs sound energy, such as acoustic mineral wool.

3. 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.

4. 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.

5. 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.

6. 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.

7. Cavity stop – This is a proprietary product or material such as mineral wool (fibre) used to close the gap in a cavity wall.

8. Composite Resilient Batten – This is composed of a timber batten with a pre-bonded resilient material to provide isolation between the flooring surface layers and floor base.

9. Cradle/Saddle -This is an intermediate support system (with a resilient layer base, either pre-bonded or already integral) using levelling packer pieces to support a timber batten, isolating it from the floor base.

10. Decibel (dB) – This is the unit used for different acoustic quantities to indicate the level with respect to a reference level.

11. Density (kg/m3) – This is the mass per unit volume, expressed in kilograms per cubic metre (kg/m3). Blockwork is commonly referred to by industry in terms of strength (in Newtons). However, it is the density that has the important role in terms of sound insulation.

12.Direct transmission – refers to the path of either airborne or impact sound through elements of construction.

13.DnT,w – This is the weighted standardized level difference. A single-number quantity (weighted) which characterises the airborne sound insulation between two rooms, in accordance with BS EN ISO 717-1:1997

14. Façade Testing – This Standard – ISO 140-5:1998) specifies the testing methods to evaluate the sound insulation in buildings and building elements for facades. Three rounds of a proficiency testing scheme for airborne sound insulation measurements have been performed according to the methods specified in the standard for a whole facade by using an external loudspeaker as the noise source.

15. Flanking element (flanking wall) – This is any building element that contributes to the airborne sound or impact transmission between rooms in a building which is not the direct separating element (i.e. not the separating wall or separating floor).

16. 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.

17. 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.

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

19. 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.

20. 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.

21. 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.

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

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

24. L’nT,w – 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.

25. Mass – This is a physical quantity that expresses the amount of matter in a body. Walls and floors may be described in terms of the surface density (mass per unit area, kg/m2) of the wall face or the floor surface, which is the sum of the surface densities of each component of the construction. The density of materials is expressed as mass per unit volume, kg/m3, which can be provided via the core structure and linings such as in-situ concrete or solid dense block walls.

26. Mass per unit area (or surface density) – This is is expressed in terms of kilograms per square metre (kg/m2). This is often used to describe boards, panels, flooring and dry linings (see gypsum based board).

27. Resilience – This can reduce structural vibration transmission and still maintain material performance and overall dimensions, examples include floating floor treatments such as resilient battens or cradles, or resilient ceiling bars.

28. Resilient ceiling bars – This acoustic solution is generally metal based and vary in thickness from 11 mm to 30 mm. They are mounted perpendicular to the joist span direction and can increase both airborne and impact sound insulation. Care should be taken to ensure that the ceiling board fixings into the resilient bar do not come into contact with the joists and reduce the potential performance.

29. Resilient noggin – This is a small section of resilient ceiling bar which is used to assist in bracing non load bearing partitions.

30. Rw – This is a single-number quantity (weighted) which characterises the airborne sound insulation of a building element from measurements undertaken in a laboratory, in accordance with BS EN ISO 717-1: 1997

31. Sound Insulation Testing – Sound Insulation Testing is required near the end of a development to show that the performance of the party wall and floor partitions meet the standards as stipulated in Building Regulations Approved Document E. The testing methods for airborne and impact sound insulation is in full accordance with the suggested methods presented in BS EN ISO 140-parts 4 & 7: 1998.

32. Stiffness – This is can improve low frequency sound insulation, for example in floors, by reducing the potential for deflection or movement of the primary structure, therefore the correct spacing and depth of joists is important.

If you require sound testing, please don’t hesitate to contact us. Using our many years of experience we can help you achieve compliance with Approved Document E.