IMPROVING SOUND INSULATION ON LONDON REFURBISHMENT PROJECTS

IMPROVING SOUND INSULATION ON  LONDON REFURBISHMENT PROJECTS

Many of our new clients ask ‘ how can we improve our sound insulation on our London Refurbishment projects’. One of the main problems is that a large number of the dwellings in London, consist of flats converted from large Victorian houses. Unfortunately at the time of the building conversion, designing for sound insulation was not a high priority and so many of the dwellings suffer from adverse noise transference between the floor and wall partitions. This can be extremely stressful to the occupant’s well being is a major cause for concern.

There are ways to improve the airborne and impact performance by improving the wall/floor partitions ability to reduce the amount of sound transmission from one side of a construction element to the other. By isolating the different materials may not be enough its own and you may need to improve the mass of the partition as well.

Video Showing Main Noise Transference Points Through Existing Partitions.

Improving Existing Floor Partitions

In our experience of undertaking hundreds of sound insulation tests in London, refurbishment projects usually achieve 30-35dB for airborne sound and 70dB for Impact Sound, if the existing construction has not been acoustically upgraded. These figures do not meet the required 43dB & 64dB as stipulated in Part E of Building Regulations. As sound double every 10dB this is a massive failure and acoustic improvements must be made. Many existing construction consist of a similar construction as shown in as detail 1 below.

Detail 1: Existing Floor Partitions Rated At Approx. 30dB

 Failed_sound_Testing_Due_to_existing_floor_Construction_

Acoustic Improvements to Existing Floor Partitions

To reduce airborne and impact sound transmission this usually means adding density and isolation to the floor construction. This can be as simple as adding a drop ceiling consisting of 125mm timber frame. The top of the frame must be a minimum of 25mm below the existing ceiling finish – such as lathe and plaster. Then, to the inside of the timber frame add 100mm of Acoustic Wool and two layers of sound-board tacked to the bottom of the timber frame – all boards to be lapped. This should improve your sound test results by approx. 10-15dB depending on the existing site conditions and quality of the installation. Detail 2 shows this in more detail.

Detail 2: Acoustic Flooring Partition Upgrade

Simple_floor_upgrade_to_Pass_Sound_Testing

If you would like advice on your acoustic design or require sound insulation testing in London, please contact us now on 07775623464 or contact us at info@aptsoundtesting.co.uk.

The Method for Sound Insulation Testing

The Method for Sound Insulation Testing

The method for testing for airborne and impact sound insulation testing methods is clearly presented in BS EN ISO 140-parts 4 & 7: 1998. The sound insulation rating methods that follow are defined in:

 DnTw

The single figure rating method that gives the airborne sound insulation performance between two adjacent rooms within a building as measured within site conditions. The result achieved is affected not only by the separating element also by the surrounding structure and junction details.

 Rating Method – Ctr

The Ctr adaptation term is a correction that can be added to either the RW (laboratory) or DnTw (site) airborne rating. The Ctr term is used because it targets the low frequency performance of a building element and in particular the performance achieved in the 100 – 315 Hz frequency range. This term was originally developed to describe how a building element would perform if subject to excessive low frequency sound sources, such as traffic and railway noise. This rating is expressed as RW + Ctr and allows the acoustic designer to critically compare performances. The rating method has not been universally welcomed.

 RW

This single figure rating method is the rating used for laboratory airborne sound insulation tests. The figure indicates the amount of sound energy being stopped by a separating building element when tested in isolation in the absence of any flanking paths.

Rating Method – Lnw

This single figure rating method is the rating used forclaboratory impact sound insulation tests on separating floors. The figure indicates the amount of sound energy being transmitted through the floor tested in isolation, in the absence of any flanking paths. With impact sound insulation, the lower the figure the better the performance.

Rating Method – LnTw

The single figure rating method that is used for impact sound insulation tests for floors. The figure indicates the sound insulation performance between two adjacent rooms within a building as measured on site. The result achieved is affected not only by the separating floor but also by the surrounding structure, e.g. flanking walls and associated junction details.

 Rating Method – Dncw

The single figure laboratory rating method, which is used for evaluating the airborne sound insulation performance of suspended ceilings. Laboratory tests simulate the room-to-room performance of the suspended ceiling when a partition is built up to the underside of the ceiling with sound transmitted via the plenum.

sound testing equipment

APT Sound Testing is UKAS accredited to undertake both Sound Insulation Testing and is also accredited to ISO 17025:2005 ‘General requirements for the competence of testing and calibration laboratories’. If you would like more information in regards to sound insulation testing and/or acoustic design, please contact us now at: info@aptsoundtesting.co.uk or call us on 07775623464

Dealing With Noise Flanking Issues

Dealing With Noise Flanking Issues 

One of the easiest ways of dealing with noise flanking issues is to use isolation strips around the perimeter of the partitions at the edges of floors and walls. Acoustic sealant should also be incorporated wherever possible. One of the main reasons for flanking sound test failures is when the inner leaf of the perimeter wall is built with light weight blocks. This acts like a large snare drum and the sound simple travels straight up the wall from one flat to the flat above and/or below. Even if you have used a acoustically robust wall and/or floor partition the sound insulation testing may still fail. If you have used lightweight blocks in your onsite construction and the building fails the sound testing you may need to construction independent internal plasterboard lining throughout the inner perimeter wall, this should isolate the lightweight blocks and ensure the flanking path is minimized.

This video shows noise flanking through a window reveal.

https://www.youtube.com/watch?v=edhLno7LFzY

To reduce the chance of sound insulation test failures, it is imperative that flanking transmission is considered at the design stage and any construction detailing is specified to minimise any potential of noise flanking which will downgrade the acoustic performance. Good detailing at the design stage will minimise this effect and optimise the overall levels of acoustic privacy achieved. If designing for residential units, design advice on flanking details must be followed to maximise the possibility of achieving the specified acoustic performance. It is imperative that the design advice is followed, otherwise the site sound insulation values may not meet the performance criteria required and subsequent expensive remedial treatment may be required.

 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.

 If you would like more information in regards to sound insulation testing and or acoustic design advice, then please call us now at info@aptsoundtesting.co.uk or call us on 07775623464.

Sound Insulation & Noise Flanking

Sound Insulation & Noise Flanking

Sound insulation & noise flanking describes the reduction of sound that passes between two spaces separated by a dividing element, such as a wall or floor partition. The sound energy passes through the dividing element (direct transmission) and through the surrounding structure (indirect or flanking transmission). The  noise reduction attributed to the sound insulation is realised via sound insulation testing.

 When the building’s acoustic design is taken into consideration, it is important to consider both methods of transmission. The dividing walls or floors, which flank/abut the dividing element/s, usually constitute the main paths for flanking transmission, but this can also occur at ventilation ducts, doorways, windows etc. If windows are positioned very close to the dividing partition then noise flanking will usually occur around the main building envelope, thus rendering your ‘high spec’ acoustic solution useless.

sound testing equipment

It is extremely unlikely that figures quoted from ‘laboratory sample’ sound test conditions will be achieved on site, as the laboratory installation is described in detail and followed to the letter. However, due to time constraints etc. it is not always possible to replicate the same conditions on a construction site, which is the reason why a 5dB point difference is allowed between the laboratory and construction site sound insulation performance.

Noise Flanking Paths

Flanking sound is defined as sound from a source room that is not transmitted via the separating building element e.g. the wall or floor partition. The sound is transmitted indirectly via paths such as external walls, windows, doors and internal corridors.

NoiseFlankingWall

If you would like more information on sound insulation testing and/or acoustic design service, please contact us at info@aptsoundtesting.co.uk or call us on 07775623464

Excess Noise Between Dwellings

The Reasons for Excess Noise Between Dwellings

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:

  • Poor workmanship at the time of construction has led to poor sound insulation and noise flanking due to bridging the acoustic elements via incorrect fixings etc. and its damaged the original components.
  • 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 and increase in noise.
  • Changes have been made to the existing construction which has had a negative impact on the sound insulation
  • 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.
  • 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.
  • The upgrading of the existing windows to double and/or triple glazing has reduced external or background noise through the building façade, thus making neighbour noise more noticeable through separating walls and floors.
  • New cut outs in the existing wall to hide new cable for the wall mounted LCD TV’s is another popular reason for noise bridging through walls.

Other factors may have an impact on the overall noise levels, such as when new neighbours move in. Occupants may be more aware of sound insulation issues due to different living patterns between neighbours.

Upgrades or changes to the buildings structure, i.e. previous service works for water pipes, drainage and heating systems may have removed acoustic materials or interfered with acoustic isolation. This can lead to a wide disparity in performance between damaged and undamaged floors or walls.

In our experience, one of the most common triggers for noise complaints is the change of a room surface e.g. from carpet to wooden laminate flooring or floor tiles.  This can typically lead to a 10-20dB reduction in insulation performance. This can lead to neighbours below the apartment changing their assessment of impact noise from “acceptable” to “intolerable”. This can often lead to protracted and expensive legal issues especially if your lease doesn’t allow for hard surface upgrades.

Noise_Problems_Failed_Sound_Testing

People who live in detached houses or well-insulated attached houses may never have experienced hearing noise from neighbours, so when they move into a flat or attached dwelling they may feel that the level of sound insulation is poor, when infact it complies with Building Regulations Part E.

If you suspect that your noise levels are too high and you would like us to undertake sample sound insulation testing, or you would like us to investigate your noise complaints, please contact us now at: info@aptsountesting.co.uk  or phone us on 07775623464

Sound Testing In House Conversions

Sound Testing Results in House Conversions.

 Due to the housing shortage many houses are being converted into flats, which has resulted in a massive spike in noise complains amongst neighbours in such developments. Much of this rise in complaints are due to insufficient acoustic design at the start of the project, this means the dividing partitions are not being designed or constructed to comply with Part E of Building Regulations for Conversions.

 In our experience many of the sound insulation tests we undertake on refurbishment projects achieve 30-35dB for airborne sound, which is well below the required 43dB as stipulated in Part E. For impact sound testing, the figures are usually around 70dB which is well above the required 64dB, which is also a massive failure.

 Taking the above into account is it essential that the acoustic design is addressed right from the start of the refurbishment project.  The usual existing construction is 175mm joists with floorboards attached to the top and a single layer of plasterboard – as per the below detail:

Failed_sound_Testing_Due_to_existing_floor_Construction_

Upgrades or changes to the buildings structure, i.e. previous service works for water pipes, drainage and heating systems may have removed acoustic materials or interfered with acoustic isolation. This can lead to a wide disparity in performance between damaged and undamaged floors or walls.

 To overcome many of these issues we can visit site and undertake sample 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. it may be as simple as the installation of an acoustic resilient layer on the floor, or a minor wall upgrade.

Precompletion Sound Testing Throughout London

Precompletion Sound Testing Throughout London 

To help enforce good acoustic design principles pre-completion sound testing was introduced July 2003, this resulted in all new build properties and conversions which were built after this date are require 10% of each party wall/floor construction type to be tested. APT Sound Testing undertake precompletion sound testing throughout London.

Precompletion Sound Insulation Testing is carried out between pairs of rooms separated by party walls or floors. The two ‘habitable’ areas that usually require sound testing are living rooms and bedrooms, although other rooms can be tested if this is not possible, i.e. kitchen to bedroom. Here is a quick description of the tests:

sound testing

Airborne Sound Tests

Airborne Sound Tests may be required between horizontally and vertically separated pairs of rooms. The sound tests are undertaken by using a sound source, amplifier and loudspeaker to generate a high noise level in one room (the source room). Noise measurements are then taken in both the source and receiver rooms using a prescribed number of source and microphone positions.

Impact Sound Tests

For vertically separated rooms, an Impact sound testing may also be required. This sound test is undertaken using a “tapping machine”, (as above) which drops a series of weights onto the floor of the upper room. The noise level in the lower (receiver) room is measured for a prescribed number of source and microphone locations. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured.

Required Sound Test Levels

The Building Regulation Part E set minimum performance requirements for sound insulation requirements between spaces. To help you better understand the sound level requirements of Part E, we have collated an easy to follow table – shown below.

Table 1a: Dwelling-houses and flats – performance standards for separating walls, separating floors, and stairs that have a separating function.

Airborne sound insulation
DnT,w+Ctr dB
(Minimum Values)

Impact sound insulation
L’nT,w dB
(Maximum Values)

Purpose built
Walls
Floors and Stairs

45
45

N/A
62

Material change of use
Walls
Floors and Stairs


43
43


N/A
64

Whatever the problem APT Sound Testing can usually find an acoustic solution that will satisfy Part E of Building Regulations. If you have a project that’s needs acoustic design advice or needs sound insulation testing then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 0203 669 2650 and we should be able to offer you an expedient acoustic solution to help you achieve practical completion.

 

Pathway To Successful Sound Testing

Pathway to Successful Sound Testing 

We have undertaken hundreds of sound throughout London and the South East and have managed to streamline our pathway to successful sound testing. We also offer robust and cost effective acoustic design advice to ensure your compliance with Part E of Regulations. Our usual pathway for successful sound testing is:

1. Our Acoustic Design Service

2. Acoustic Site Audits

3. Precompletion Sound Testing

 

Acoustic Design Service

On our experience some of the most common mistakes during the construction are as follows:

  • Using lightweight blocks in the inner envelope construction as sound will travel along light block-work both vertically and horizontally from dwelling to dwelling.
  • The use of resilient suspended ceilings will help improve the performance of the floor partition.
  • Not incorporating a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.
  • Ensuring all penetration’s are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.

sound testing equipment 

Acoustic Site Audits

We can undertake acoustic site audits, to let us view the existing site construction. This allows us to check for potential problematic areas such as the inclusion of lightweight blocks within the existing wall construction. It also lets us check that the installation teams are installing the acoustic materials as per manufacturer’s guidelines, thus avoiding crucial onsite mistakes. In our experience a sound test failure is often due to the poor workmanship rather than the actual design. The site survey visits negate the risk of sound test failure.

We can also undertake 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 which takes into account the performance of the existing construction.

 

Defect Diagnosis & Remedial Advice

With many years’ experience in building acoustics, we are able to diagnose the reasons for the sound test failure and recommend a cost-effective solution. Often, the reasons for the partition failure are obvious to the test engineer in which case the advice will be minimal and subsequently the cost for acoustic design advice will be minimal. Sometimes, there are more technical issues which require more detailed diagnosis and invasive investigation, such as large amounts of noise flanking due to serious design faults, e.g. poor material isolation.

 

Precompletion Sound Testing

To help enforce good acoustic design principles pre-completion sound testing was introduced July 2003, this resulted in all new build properties and conversions which were built after this date are require 10% of each party wall/floor construction type to be tested.

Whatever the problem we can usually find an acoustic solution that will satisfy Part E of Building Regulations. If you have a project that’s needs acoustic design advice or needs sound insulation testing then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 0203 669 2650 and we should be able to offer you an expedient acoustic solution to help you achieve practical completion.

 

Failed a Sound Test?

Failed a Sound Test?

If a client has failed a sound test, they often ask us for the reason why. It is almost certainly the result of a combination, of the following items:

  • Poor acoustic advice
  • Poor onsite installation
  • Flanking noise which comprises the sound insulating element.

Unfortunately, if you fail the sound testing its not easily rectified, as it usually means a major upgrade to the failed partition and thereafter another sound insulation test, which is both costly and time consuming.

If you do find yourself in this unfortunate situation, the first thing to do is contact APT Sound Testing your ‘friendly acoustic consultant’. We will be able to advise you on how to undertake minor acoustic upgrades, once we have obtained a copy of the failed sound test report. We can then ascertain the potential weak acoustic elements from the graphical results, and advise on a robust acoustic solution to building regulations Part E.

We will also be happy to liaise with your architect to ensure that all areas have been covered in the initial/remedial acoustic design. For a small fee we can visit site and undertake an ‘onsite design review’; or, do a an office based design review which cuts costs even further – to do this we would need all plans and sections relating to the project.

NoiseFlankingWall

Problems with airborne and structure borne sound are often associated with direct flanking transmissions through floors, supporting walls and other associated structures. You need to establish if your problem is due to direct transmission, flanking transmission or a combination of both so that the most effective remedial treatment can be chosen to suit.

First you need to understand how the sound is travelling into your home. It may be coming directly through the separating partition, i.e. wall or floor or it may be coming along another indirect route – called a noise flanking path. The most common such flanking path is the inner leaf of an external cavity wall.

If you have suffered a sound test failure and/or you require acoustic design advice then please email us in info@aptsoundtesting.co.ukor phone our design manager Darren on 07775623464. We have the experience, professionalism and acoustic know how to ensure that your project can achieve Part E of Building Regulations.

SOUND TESTING ON LONDON DEVELOPMENTS

 SOUND TESTING ON LONDON DEVELOPMENTS

London is a massive city containing over 8 million people. In this overcrowded environment it is essential that noise transference between adjoining properties in kept to a minimum for the occupant’s well being.

When there are problems with noise transference between dwellings, and the building’s design is called into question, we can offer advice on how to upgrade the wall and/or wall partition to improve the sound insulation values.

We have extensive knowledge regarding the way different materials and construction methods can influence the results of a sound test and subsequent noise transference, this helps to ensure your company achieves compliance with the Sound Testing for Part E of Building Regulations at pre completion stage.

Pre completion sound testing in London 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. Sound insulation testing is to be carried out between pairs of rooms separated by party walls and/or floors. In is usual to test 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 study’s, kitchens and dining rooms.

Also, we are also experiencing a rise in the amount of sound testing that’s required to existing London buildings which isn’t surprising as the amounts of noise complaints to councils has doubled in the last 10 years, as a result we have carried out a large amount of sound tests in council/housing association blocks, where the residents are experiencing excess noise between the dividing wall and floor partitions.

We also undertake sound testing to existing flats where the lease stipulates that wooden floors should not be used instead of carpets and as a result of the change of floor finishes the noise levels have increased through the floors – especially the impact noise.  In all these instances we can undertake sound testing to highlight the existing noise levels so acoustic upgrades – if required) can be targeted and implemented, i.e. it may be as simple as installing an acoustic membrane on the floors below the timber floor.

sound testing equipment

The airborne sound testing is undertaken by using a sound source, amplifier and loudspeaker to generate a high noise level in one room (the source room). Noise measurements are then taken in both the source and receiver rooms using a prescribed number of source and microphone positions. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured. From the results the airborne sound insulation (DnT,w + Ctr) is calculated and compared to the requirements of Approved Document E.

For vertically separated rooms, another type of sound test called Impact sound testing may also be required. This sound test is undertaken using a tapping machine which drops a series of weights onto the floor of the upper room. The noise level in the lower (receiver) room is measured for a prescribed number of source and microphone locations. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured. From the results, the impact sound insulation results (LnT,w) is calculated and compared to the requirements of Approved Document E of Building Regulations.

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

If you would like advice on your acoustic design or sound testing in London, please contact us now at info@aptsoundtesting.co.uk or call us on 07775623464.