Improving Sound Insulation on Conversion Projects

Improving Sound Insulation on Conversion Projects

In cities throughout the UK there are a huge amount of conversion projects where large Victorian or Georgian houses – or more recently office blocks) have been converted into flats or rooms for residential purposes. Unfortunately designing for sound insulation is not always shown the highest priority on these types of projects, so many converted 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.

architect drafting a house blueprint

architect drafting a house blueprint

We have helped many of our clients achieve compliance with Part E, by undertaking some simple steps. We can undertake an initial sample sound test of the existing wall and floor construction to ascertain the existing sound insulation levels. Once we have established the sound levels for the existing construction, we can then look at extent of the acoustic upgrades to attain Part E Compliance. This is much more effective than just forwarding an acoustic design that may be to excessive and expensive, especially if the existing floor and/or wall only needs to improve by a minimal amount such as 1-3dB. By having the existing sound levels of the partitions we can recommend targeted, acoustic upgrades to comply with Building Regulations Part E.

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=The sound insulation levels required to pass Part E for refurbishment projects are less stringent than new build projects. Instead of 45dB for airborne its 43dB (2 dB less), and for instead of 62dB for Impact Sound Testing its 64dB on new build (2 dB more).

Taking the above into account is it essential that good acoustic design is addressed right from the start of the refurbishment project, so it prevents delays in handover, i.e. to prevent the dwelling failing the sound testing at building control sign off stage.– a common problem.

We have offered design advice on hundreds of conversion projects, so we have the experience to help you comply with Building Regulation Part E and achive a sucsessful sound test. 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.

 

Noise Flanking Paths

Noise Flanking Paths

To reduce the chance of sound testing failure, it is imperative that flanking transmission is considered at the design stage to reduce potential noise flanking paths. 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.

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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. One of the easiest ways of dealing with sound flanking issues is to use isolation strips around the perimeter of the partitions at the edges of floors and walls, this should be finished with acoustic sealant

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 test 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.

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@airpressuretesting.net or call me (Darren) direct on 07775623464.

Sound Testing Rating Methods

Sound Testing Rating Methods

Sound tests are broken down into various sound testing rating methods. The sound insulation definition and terms are as follows:

Rating Method – 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.

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Rating Method – 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. Some acoustician believe that the method is too crude as it only considers the low frequency performance, and because site measurements at low frequencies are prone to difficulties, which can lead to a lack of confidence in the results achieved.

Rating Method – Lnw

This single figure rating method is the rating used for laboratory 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

This is a 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.

If you have a project that’s needs acoustic design advice or sound insulation testing, then please contact us at: info@aptsoundtesting.co.uk or phone me (Darren) directly on 07775623464.

Sound Test Procedure

Sound Test Procedure 

The Sound Testing procedure is fairly simple and our engineer will be happy to explain this on site. Essentially, for party walls there is one type of sound insulation test which is airborne sound test and for compartment floors there are two types of sound insulation tests which are airborne and impact sound insulation tests. The airborne sound insulation test is carried out by means of a loudspeaker emitting a steady source of noise on one side of the partition (wall or floor) to be measured. The corresponding sound level is measured on the other side of the partition. Impact sound insulation tests are carried out by means of a tapping machine placed on the floor sample to be measured and the noise measured in the room or space below.

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All our engineers carry out the sound test measurements in full accordance with the measurement procedures of BS EN ISO 140-4:1998[3] for field measurements with a single figure DnTw and LnTw in accordance with BS EN ISO 717.

Ongoing problems with airborne and structure borne sound are often associated with direct noise flanking transmission through floors and supporting walls and other associated structures. One common cause of noise flanking is often associated with the inclusion of lightweight blocks within the construction of the building envelope and/or blocked cavities. It all cases it is essential to establish if your problem is due to direct transmission, flanking transmission or a combination of both so that the most cost effective remedial treatment can be chosen.

We offer both pre-construction acoustic design advice and  we can also help if your building has failed the Part E sound test. We also offer onsite inspection services to ensure that the sound insulation elements are being installed as per manufactures guild-lines.

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

Sound Insulation Testing in London

Sound Insulation Testing in London

London is a massive city containing over 9 million people density and high rise apartments. With many living in this overcrowded environment it is essential that noise transference between adjoining properties in kept to a minimum for the occupant’s well-being. 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 London.

Sound_Testing_Flats

We have undertaken thousands of sound insulation tests throughout London and the South East on all types of projects from simple flat conversions to large developments containing hundreds of flats. We also undertake Sound Insulation Testing where a lease holder dispute 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.

Plate A – Tapping Machine for Impact Sound Testing

Impact Sound Testing

Currently we are also experiencing a rise in the amount of sound testing required to existing blocks of flats, such as existing council stock. This is hardly surprising as the amounts of noise complaints have more than doubled within the last 10 years due to residents experiencing excess noise between the dividing wall and floor partitions.  By utilising our extensive knowledge of different materials and construction we can forward a simple, explanative cost effective solution for wall and/or floor upgrade. Where our clients have followed our advice they have achieved a 100% success sound test pass rate ensuring compliance with Part E of Building Regulations.

APT Sound Insulation Testing offer both preconstruction and post construction design solutions if a project has failed the sound testing. We also offer onsite inspection services to ensure that the sound insulation elements are being installed as per manufactures guild-lines.

If your require pre-completion sound testing and/or you would like acoustic design advice on your project, please contact us now at info@aptsoundtesting.co.uk.

The Two Types of Sound Insulation Test

The Two Types of Sound Insulation Test

There are two types of sound insulation testing, Airborne and Impact.

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.

Sound_Insulation_Testing_Equipment

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 absorptive characteristics 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.

The time taken to undertake sound testing varies from project to project as no site is exactly the same. Taking into account standard site conditions a set of tests on houses -two airborne walls will take one to two hours. A six pack of tests on flats – 2 airborne wall tests will usually take between one and two hours, although this is dependent on our engineers having full free uninterrupted access between all the units/rooms under investigation.

If you require sound insulation testing, or acoustic design advice then please contact us now at info@aptsoundtesting.co.uk  or phone me (Darren) directly on 07775623464.

Why do my Floors Squeak?

Why do my Floors Squeak?

We often receive complaints from clients in regards to their floors creaking. This is often because the Joists are often spaced too far apart, which can result in a reduction in floor stiffness. Over-notching of joists can also lead to a reduction in floor stiffness and also potential squeaking. Although the floors may pass the airborne and impact sound testing, however it won’t stop the squeaking of the floors under the extra load imposed by people walking above.

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Other problems may be down to the contractor using 12mm floor boarding instead of 18mm to the top of the joists, again this may allow the boards to move and squeak. It may also be down to the chipboard not sitting level across the joists, this may down to the  joists being installed at slightly the wrong level or a joist hanger may have been hit or come loose during the build. If the joist has been built into the wall the bearing could be unsatisfactory. it may be as simple as a missing joist, or cut edge unsupported or an over span on the joists.

  • Incorrect bridging of resilient layer by over-long screws/nails
  • Fixings connecting ceiling boards to resilient bars should not bridge to joists
  • Extra wide joist spacing that reduces floor stiffness
  • Platform floor resilient layers damaged by inserting pipes and services within the layers
  • Reduction in stiffness due to use of joist hangers
  • Ceiling boards not staggered
  • Over-notching of joists for services reduces floor stiffness
  • Incorrect omission of flanking strips at floor edge perimeters.

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

If you have a project that requires acoustic design advice and/or sound insulation testing, then please contact us at: info@aptsoundtesting.co.uk or phone me (Darren) on 07775623464.

A Successful Sound Insulation Test

A Successful Sound Insulation Test

There are many considerations to achieving a successful sound test on your development. The main areas that need to be addressed are the dividing wall and floor construction.

When dealing with walls you normally just need to worry about airborne sound; however with walls it’s both airborne and impact sound which can be far more difficult to deal with.

sound_transmission_through_floors

The usual noise problems associated with airborne sound transmission is TV noise, music and speech. This can be dealt with by applying ceiling treatments as well as mass and isolation to the building components. Impact sound (footfall) performance is increased by the used of resilience layers and isolation of components to prevent noise flanking through the partition.

Airborne Sound Testing

For airborne sound insulation testing Building Regulation Part E requires you achieve at least 45dB for new build properties and 43dB for conversion developments, this applies both to party walls and floors between properties. This level is the difference between the source level and the receiver level during sound testing. Impact Sound TestingThe measurement is corrected for several factors such as background noise, room characteristics and frequency weighting, giving the final sound insulation performance value of the tested partition. In this case the higher the number the better the sound insulation performance. The measurement is done by using a Class 1 Analyser and the associated equipment.

Impact Sound Insulation Testing

For impact sound insulation testing Building Regulation Part E requires you achieve at least 62dB for new build properties and 64dB for conversion developments. Impact insulation performance only applies to party floors and related to the effectiveness of the floor construction in absorbing shock such as footfall noise.Sound_Insulation_Testing_Equipment

Good Acoustic Design

To try and ensure you meet the standards stipulated within Building Regulations Part E, careful consideration should be shown to the acoustic design detailing from the start of the project. Tackling the acoustic design for both new build and conversion project requires two different construction techniques and acoustic design detailing. With new build properties you have a blank canvas in terms of the overall design whereas with conversions you usually need to work with the existing’ onsite’ construction which can be quite difficult.

We offer an acoustic design package, which contains the following elements:

  1. 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.
  2. Acoustic Design Review – a full design review of the proposed developments party walls and floors.
  3. 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. Final Precompletion Sound Testing in compliance with Building Regulations Part E.

If you have a project that’s needs acoustic design advice or sound insulation testing, then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 07775623464.

We have also started our new facebook page at: https://www.facebook.com/APT-Sound-Testing-1705040043131199/

Careful Acoustic Installation leads to Successful Sound Testing

Careful  Acoustic Installation leads to Successful Sound Testing

It is very important that acoustic installation details are closely followed to ensure that the onsite results are as close as possible to the laboratory target. It is pointless having good acoustic design detailing if this is not carefully followed on site.

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The following list explains what should during the onsite construction process to achieve a successful onsite sound tests and Part E compliance:

  1. Ensure that the construction team is fully briefed of the acoustic details.
  2. Ensure that the manufactures installation booklet is on site at all times.
  3. Ensure that the Acoustic floor is fitted with staggered joints.
  4. If you are installing floating screed ensure all isolation layer joints are overlapped and taped.
  5. Ensure all the Acoustic floor is sealed watertight even around heating pipes.
  6. Do not nail or screw through an Acoustic Floor.
  7. Do not screws plaster board into joists, when using a Resilient Bar system.
  8. Ensure the insulation fills the whole width of void
  9. Pack around pipe work and double board with staggered joints.
  10. Ensure that the plasterboard on any walls is complete right down to within 5-10mm of the subfloor and seal all gaps.
  11. Ensure you use the isolation tape around the wall of each room.
  12. Ensure plasterboard is fitted with staggered layers and all joints sealed.
  13. If using Resilient Bars ensure that they are fitted as per manufacturer’s recommendations.
  14. Ensure all Fireplaces are blocked up with brick or a twin lined plasterboard system and filled with acoustic insulation.
  15. Ensure that any RSJ’s or supporting steel work is insulated and isolated from plasterboard.
  16. Ensure all waste pipe service runs are boxed in with insulation and plasterboard.
  17. Ensure all doors and windows are installed before the test is carried out, to stop noise transference.

We offer an acoustic design service which includes site visits to make sure the acoustic elements are being installed as per the manufacturer’s guidelines. If you are worried about passing your sound testing at the first attempt please don’t hesitate to contact us now at: info@aptsoundtesting.co.uk or call Darren Direct on 07775623464.

The Difference Between Laboratory and Site Sound Testing

The Difference Between Laboratory and Site Sound Testing

Many suppliers of acoustic insulation products quote laboratory sound test results  to demonstrate the performance of their systems. This often causes considerable confusion regarding how well products will perform as there are usually large differences between the laboratory and site conditions. For instance laboratory sound tests do not take account of flanking sound and therefore produce sound insulation figures that would be very difficult to achieve on site.

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Despite site contractor’s best endeavours, it is extremely difficult to build to the stringent exacting standards of the test laboratory. When the construction assembly is undertaken in the lab, it has gone through an exacting installation technique prior to the sound test, which is also a contributing factor why better sound testing levels are achieved.

Throughout the acoustic installation the manufacturer’s guidance is followed to the letter by the lab technicians. Although, this should be replicated on site, it seldom is due to time constraints etc. and so a design which can be easily in excess of the requirements of approved document E, can often lose approx. 8-10dB compared to the laboratory results. Unfortunately there may be many reasons for poor sound test results such as poor quality site installation as well as other on-site issues where cost, time and programming constraints may come into play.

architect drafting a house blueprint

architect drafting a house blueprint

One important thing to consider is that most building structures will be subject to varying amount of flanking sound, so field sound test data should show the real performance of a system in a building. Laboratory sound insulation tests simply measure sound and do not account for flanking sound transmission.

If you are worried about your projects acoustic design and/or have questions about the precompletion sound testing, please don’t hesitate to contact us now at: info@aptsoundtesting.co.uk or Darren direct on 07775623464.