Decoupling of Materials

Decoupling of Materials

There are many things to consider with your acoustic design and construction, one of the first – and most important) is the decoupling of materials or also know as isolation of materials. Sound travels easily along direct construction pathways, i.e. if the construction is made up of a wooden wall frame with a layer of plasterboard fixed to either side, with this type of construction the sound has a solid mass of materials to travel across. If we “decouple the materials” it reduces the pathway for vibration and the sound levels drop accordingly.

When we design for acoustic partition construction we obviously want less sound vibration to travel from one side of the wall to the other. It is therefore hugely beneficial if we can decouple the partition framing in our walls and ceilings. Decoupling is a simple, inexpensive and highly effective way to improve the sound insulation results for Building Regulations Part E.  .

There are many types of decoupled construction that in turn offer varying degrees of separation of the drywall on one side from the drywall on the other side. For instance the image below shows a twin wall construction which is far superior to a single stud wall. if you require good sound test results, this is one of the best types of construction.

decoupled_wall_construction

By decoupling the wall studs limits by providing a cavity or break between the two walls reduces the vibration trying to conduct through the wall. although this will improves the airborne results, other improvements will still be required.  So although our decoupled framing system reduces a good deal of vibration, we need to continue to the other 3 elements, absorption, mass, and to damping to reduce the noise more effectively.

Our next blog will consider absorption and how it can make a  large difference to sound test results. If you would like more information to acoustic design and/or sound insulation testing please contact us at: info@aptsoundtesting.co.uk or call Darren on 07775623464.

The Main Sound Proofing Elements

The main Sound Proofing Elements

Coupled Wall Construction

We often get asked ‘how can we improve our soundproofing on our development. The first thing to understand is the basic of soundproofing design and construction. If you understand the basics, you’ll have a more educated view point in regards to the way sound and vibration behaves within your new dwellings. Basically, we want to stop sound and vibration through the walls and floors of your development and one of the best ways of doing this is avoiding coupled wall construction. In general, we are trying to stop vibrations from getting to “your” side of the wall or ceiling.

The plate below shows a typical wall and noise problems associated with it. With this type of construction noise transference is a big problem. If there is even moderate levels of noise on one side of the wall the chances are you will hear it.

coupled_wall_construction

If you look at the red arrows in the above diagram it clearly shows how sound is conducted from one side of the wall to the other. As the wall elements are firmly fixed against each other, i.e. the plasterboard is rigidly connected to the timber, the vibration conducts straight through the whole wall construction.

If you look at the blue waves this indicates airborne transmission. The plasterboard is vibrating back and forth which produces a sound wave in the wall cavity. This, in turn, vibrates the plasterboard on the opposite side of the wall. the whole construction acts like a  huge diaphragm or like a large speaker with both sides of the wall vibrating in unison, which is not ideal.

Our next blog will explain how we can reduce noise transmission by decoupling the wall construction. if you would like more information on our sound testing or acoustic design services please contact us now at: info@aptsoundtesting.co.uk or call Darren direct on 07775623464.

Noise Problems in Refurbished Industrial Buildings

Noise Problems in Refurbished Industrial Buildings

We often get asked to undertake a series of sound test measurements to establish the acoustic performance of the wall of floors construction in existing buildings where the dwelling owners are concerned about excess noise.

In recent years the refurbishment of old industrial buildings into residential dwellings has become a very popular. Frequently the existing finishes of existing concrete, brick or wood Noise Problems in Refurbished Industrial Buildingsare left as the interior finish, supposedly to provide the “loft” type of décor. Such designs require even more acoustic design attention if sound privacy is to be achieved. Potential noise problems in refurbished industrial buildings can be quite challenging so buyers should insist that actual on-site sound insulation testing is undertaken to check the building has complied with the sound design performance criteria of Building Regulations Part E.

sound_transmission_through_floors

If you think you have a sound problem in your dwelling and are seeking help to resolve the problem, be sure to contact us and describe the problem in as much detail as possible. Describe the nature of the sounds, when and where you can hear it. Is it impact noise or airborne noise or a combination of both? If the unit is of recent construction you may need to procure a set of architectural drawings and mark-up which partitions noisiest. The more information you can provide us, the quicker we can try to determine the nature of the problem and subsequently find an acoustic solution for the partition/s.

We can also visit site and undertake sample testing on the dividing partitions. If the partitions fail the tests we can identify the main reasons for the sound test failures so targeted remedial treatments can be undertaken.

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

 

Sound Transmission Though Windows

Sound Transmission Though Windows

One source of great annoyance is often due to sound transmission though windows, this can be down to a variety of factors. If the windows are operable types, the first thing to check is to see if the widows close properly against their seals and any weather stripping is continuous and in good order. If the window leaks air, then more often than not it will usually leak sound. If the window closes to form a tight seal and the weather-stripping seems adequate the next thing to check is the window frame.

Noise_Problems_Failed_Sound_Testing

Windows are frequently installed in to the wall opening with plastic shims to insure the unit is plumb and level. The space between the frame and the wall should be insulated and sealed before the window casings are installed. If this was not done correctly you can probably detect the sound leakage by placing your ear close to the frame and listening.

Usually double pane windows have poor noise-stopping capabilities. This may be overcome by installing a layer of lamination. Many manufacturers offer this service but it can be quite costly. Although double pane windows do stop a bit more noise than single pane windows it is still not very effective. In a noisy environment, you would hardly notice the difference.

Part of the problem is down to the construction of double pane windows; this is because the two pieces of glass are coupled within the same frame and vibrate together, similar to a tuning fork. Sound insulation, however, is increased markedly by using a double pane system and replacing air by argon between the panes.

In some cases the thickness of the glass maybe the problem in which case it may be necessary to install another layer of glass on the inside of the existing frame making sure that the additional pane of glass is well sealed into the opening.

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

Ceiling and Wall Assemblies for Part E

Ceiling and Wall Assemblies for Part E 

In our experience ceiling and wall assemblies, can be the main pathways for the two main types of sound transmission. The first type is the airborne sound –  such as loud music) and the second is impact sound, such as footfalls on the floor above.

If the ceiling and wall assemblies have been designed and constructed to provide adequate airborne isolation, impact noise can still be a problem. If the finished floor surface has been designed to accommodate carpeting, the carpeting and under pad will normally provide a good degree of impact sound isolation. On the other hand, if the finished floor is floor is constructed in hardwood, stone or ceramic tile. Achieving good impact sound isolation requires much more attention at the design stage to prevent potential sound test failures.

sound_transmission_through_floors

One of the main misconceptions is sound simply passes through materials, this is not the case. Sound waves are form of energy that energises any material that the sound waves come in contact with. Thus sound energy that impacts on a wall for floor/ceiling assembly will cause the material to vibrate like a radio speaker; the energised material then becomes the transmitter of the sound energy.

Thinner, more lightweight building materials often hold the key to effective noise control, by using materials with different acoustical characteristics that will dissipate and diffuse the sound energy. Insulation in the cavity converts some of the energy in to heat while a resilient channel will help minimise the direct connection of the gypsum board from one side of the assembly to the other. Each material and its relationship to one another, produces small increases in sound isolation that in turn reduces the transmission of sound through the whole system and subsequently improves the sound insulation characteristics of the acoustic partitions.

I hope the above article helps to explain the importance material selection within acoustic design.  If you would like more information or some acoustic design advice on your project, please don’t hesitate to contact me on info@aptsoundtesting.net or call me on 07775623464.

Reducing Noise in Residential Buildings

Reducing Noise in Residential Buildings

We often get asked how noise can be reduced in residential buildings such as apartments or terrace houses. One of the most common problems is noise transmission through the floor and ceiling assemblies in flats and through the wall partitions in houses. The usual noise problems range from airborne noise transmission from voices TVs and music to footfall impact noise caused by high heels on wooden/tiled floors.

Noise_Problems_Failed_Sound_Testing

In most cases for newer residential units many of the problems could have been prevented in the first place, if more attention had been paid to noise control during the design and construction process.   If the acoustic design has not been taken into account from the off-set of the project, then it becomes far more problematic and costly if noise problems are discovered and the partitions fail the sound insulation testing during the per-completion testing.

If you are contemplating the purchase of a unit, do not be afraid to question the contractor and the real estate agents about the sound insulation results for the unit. Ask if any of the units failed during the precompletion testing. In some cases just because a sample of the units had been tested during prior to handover doesn’t mean unit has been sound tested.

If you are not happy with the sound insulation properties of your unit then you may have a case to demand corrective action at the expense of others. If you have a noise problem that is not resolved and you go to sell your unit, you may be compelled to reveal the deficiency to a prospective buyer which may have an impact on the selling price.

If you need acoustic advice on your project, please don’t hesitate to contact us no at: info@aptsoundtesting.co.uk or call me direct on 07775623464.

Our Sound Testing Procedure

Our Sound Testing Procedure

Our sound testing procedure is quite simple and our acoustic 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.

sound testing equipment

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. Calculations are done based on these measurement and the above mentioned parameters are calculated and compared to the Building Regulations Part E sound insulation requirements for the given type of the building. It is important that the building to be sound tested is completely finished and sealed with no sound leakage through doors and windows.  Please see our check list for sound insulation testing for more information.

The airborne and impact sound insulation tests carried out 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. As per the new regulations the Spectrum Adaptation Ctr which is a correction factor calculated from the measured DnT.w and the corresponding third octave band DnT values.  It uses a set of weighting levels in third octave bands derived from a road traffic noise spectrum.  It is applied to airborne test results and is measured in dB.

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

Simple Acoustic Floor and Wall Upgrades

Simple Acoustic Floor and Wall Upgrades 

There are many quick and simple acoustic wall and floor upgrades to help you achieve compliance with Build Regulations Part E. One of the easiest wall solutions is to install a 70mm met-sec partition in front of the existing wall abutting dwellings. Firstly leave approx. 25mm gap between the back of the met-sec and the existing wall. Then install 50mm acoustic wool to the inside of the met-sec and add two layers of soundboard to the outside of the met-sec frame, ensuring all boards are properly lapped and ensure the perimeter joints are kept back from the surrounding construction and filled with acoustic mastic. Also make sure that all sockets etc. are placed in a different position to the sockets on the other side of the wall to prevent noise transference.

Acoustic_Ceiling_Upgrade

To reduce airborne and impact sound transmission through the floor, one simple solution is to add a timber baton to the bottom of the joists. Then add an acoustic resilient hanger. To the inside of the newly formed void add an AW 25 Isowool acoustic insulation. To the underside of the hangers install 2 x 12.5mm layers of soundboard. Allow for the correct laps in the plasterboard and and ensure the perimeter joints are kept back from the surrounding wall construction. Add AW100 Isowool to the centre joist void and to the top of the joists install 18mm flooring. To the top of the flooring add a 4mm resilient matt.

The above Air and Wall solutions should help your project comply with Approved Document E for Sound Testing in London. 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 and we should be able to offer you an expedient acoustic solution to help you achieve practical completion.

Noise Flanking Can Lead to Sound Test Failure

Noise Flanking Can Lead to Sound Test Failure

Noise flanking can be a huge problem and one of the main causes of excessive sound transmission. If your project fails the sound testing, more often than not noise flanking will be the culprit.

To get an understanding for why the acoustic partitions are performing poorly a detailed diagnosis and invasive investigation, such as the removal of some of the wall and floor partitions will usually need to take place. In many cases a large amount of noise flanking is due to serious design faults such as the use of lightweight blocks in the construction of the walls in an apartment development, this allows the sound to travel along the walls and floors from dwelling to dwelling. In many cases a wall and/or floor partition may have a very good acoustic design and construction; however the partition will still fail as the sound is travelling along a noise flanking path.

Sound_Insulation_Test_London

We often get asked what ate the main reasons noise flanking on new and existing dwellings, in our experience they are:

  1. Where lightweight blocks used in the inner envelope construction. This allows sound to travel along the lightweight blocks both vertically and horizontally from dwelling to dwelling.
  2. Through dividing floors if there is lack of mass or acoustic insulation has not been installed and/or or direct fixing of plasterboard and/or floorboards to joists without using a resilient ceiling construction and/or floating floor.
  3. Through Windows if they are no double glazed or have secondary glazing as a minimum
  4. Through Fixtures & fittings such as light switches, telephone outlets and TV cable ducts where they sit back to back against the adjoining property.
  5. Along structural joints along the perimeter wall and floor joint. These areas should be filled with acoustic mastic)
  6. Structural steels that run through one property to the other without material isolation, i.e. plasterboard is screwed directly to the steel offering little or no noise isolation.

There are many quick and simple solutions to improve the acoustic performance of dividing wall partitions. One of the easiest wall solutions is to install a met-sec partition in front of dividing partition.

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. We should be able to offer you an expedient acoustic solution to help you achieve practical completion.

SOUND TESTING FOR LONDON

SOUND TESTING FOR LONDON

London is a massive city containing in excess of 5 million dwellings, many sharing wall and floor partitions. In this noisy environment it is essential that good acoustic design and construction is incorporated into all new and refurbishment projects along with sound testing for London.

To try and help enforce good acoustic design principles, pre-completion sound testing was introduced in July 2003 to comply with new Approved Document E. The new building regulations required 10% of each party wall/floor construction type to be sound tested on all new build and conversion properties.

We have undertaken thousands of sound tests on converted properties in London and in our experience if the partitions haven’t received any acoustic upgrades the wall and floor partitions – as per the plate below) normally achieve approx. 30-35dB for airborne sound and 68-74dB for Impact Sound. Obviously these figures fall well short of the required 43dB & 64dB as stipulated in Approved Document E. Also, it’s worth taking into account that sound doubles every 10dB, so 30-35dB for airborne sound and 68-74dB for impact sound would be massive failures and careful acoustic design and construction upgrades would be required.

Detail 1: Existing Floor Partitions (rated at approx. 30-35dB)

Failed_sound_Testing_Due_to_existing_floor_Construction_

Using our many years’ experience in building acoustics, we are able to offer a total design and testing solutions for new and conversion projects. We help many architects and top 10 construction companies with their acoustic design requirements from the largest developments containing hundreds of units through a pair of semi-detached dwellings. We always endeavour to find the best solution, always taking build-ability and cost into consideration.

If it’s a conversion project and you are unsure of the floor/wall construction, we often recommend our ‘sample sound testing service. Firstly, we visit site and undertake sample sound testing to at least one floor and wall partition, is consists of at least one airborne and impact test to the proposed dividing floor and an airborne test to the dividing wall. Once the sound test results are established we can then offer a targeted acoustic design solution to achieve a successful sound test in London in compliance with Approve Document E.

Whatever the problem we can usually find an acoustic solution that will help you achieve Building Regulation compliance  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