Month: April 2022

What can APT Sound Testing do for you?

What can APT Sound Testing do for you?

At APT Sound Testing, we offer Airborne and Impact Sound Insulation Testing in accordance with Part E of the Building Regulations and, where required sound testing on Schools BB93 & BREEAM. Under Part E of Building Regulations, this is a requirement for new and converted dwellings where there is a separating partition wall or floor. The sound insulation testing of existing buildings is carried out to assess current levels of sound insulation and to allow for the design of remedial measures, where the performance needs to be increased.

The buildings that currently require sound testing are:

  1. Dwelling-houses, flats or rooms for residential purposes created by conversion of existing buildings or new build rooms for residential purposes will need to be tested if work starts after 1 July 2004.
  2. New build dwelling-houses and flats will need to be tested if work starts after 1 July 2004.

Sound insulation testing is carried out to ensure that minimum standards of sound resistance have been met to ensure the well-being of new tenants is not compromised by adverse sound transmission. The testing checks that the dividing partitions have not been compromised by poor workmanship and poor design. We use the latest sound testing equipment as shown below:

What can APT Sound Testing do for you?

You are normally required to undertake sound testing to each type of construction, i.e. if you have a mixture of brick, blockwork, timber and metal studwork walls all four types would need to be tested, followed by a 10% sample of that type. For instance, if you have a project with 25 flats you would be required to do 3 x 6 pack of tests – 18 tests in total. Each 6 pack contains 2 airborne wall, 2 airborne floor and 2 impact sound tests; however if any test failures occur, then the number of sound tests may need to increase on the development.

We are also able to provide an acoustic design service, consisting of consisting of a new-build or conversion design reviews and site inspections, to ensure that proposed acoustic constructions and detailing of a new building will comply with the acoustic targets of the development.

What can APT Sound Testing do for you?

In our experience the usual areas of concern are:

  1. Dividing Wall Partitions – Through the wall partition if the insulation has not been installed correctly or isolation strips have not been used within the wall construction.
  2. Dividing Ceiling Partitions – Above and Through the Ceiling Space (where an adequate acoustic break has not been carried on through the ceiling void)
  3. 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)
  4. Shared Structural Building Components – Floor Boards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
  5. 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)
  6. Plumbing Chases – Junctures Between the Walls & Floor Slab Above or at the Exterior Wall Juncture (this should be filed with mortar etc. to add mass to this weakened area)
  7. Through Windows (if they are not double glazed or have secondary glazing as a minimum)
  8. Minimal dimensions between windows – if windows are built very tight to the dividing wall/floor partition this can be a weak point.
  9. Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)
  10. Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic)
  11. Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)

We can also undertake reverberation time assessments – and testing where required) for communal areas, as required by Document E of the Building Regulations. Excessive reverberance is a common problem in large spaces such as community halls etc. leading to poor audibility or speech intelligibility negating the room’s effectiveness for meetings etc.  

If you are unsure whether the Regulations apply to your development or if your site needs sound insulation testing, please call your local office or email us at where our team will be happy to discuss all aspects of acoustics or sound insulation within buildings, and explain the testing procedure.

All APT’s test engineers carry the latest sound testing equipment, and our sound testing is completed to a strict quality controlled standard. We provide full ISO & UKAS complaint sound testing. If you would like more information in regards to sound testing please contact us 01525 303905 or visit the APT Sound Testing website today.

How Many Air Tightness Tests do I need?

How Many Air Tightness Tests do I need?

How Many Air Tightness Tests do I need?

The air tightness test can be carried out on a selection of dwellings/ building types – three units of each type or 50% of that type, whichever is fewer. It many cases it is necessary to test all plots, otherwise a 2m3/hr/m2 penalty must be applied to all the plots on the site, this means that you will need to 3m3/hr/m2 if your SAP report stipulated a designed air permeability rate of 5m3/hr/m2. So to summarise the following testing will usually be required:

  • All new dwellings (based on a sampling rate)
  • All commercial new buildings other than dwellings
  • ‘Large’ extensions to buildings other than dwellings (if the footprint of the building extension is 25% of the original buildings floor area)
Air Tightness Tests

The dwelling(s) to be tested should be taken from the first completed batch of units of each dwelling type. For a dwelling to class as the same’ type’ as another it should consist of the following:

  • The same generic form, i.e. detached house, end of terraced, mid-terraced, semi-detached, ground floor flat, mid-floor flat, top floor flat, bungalow etc.
  • Have the same principle construction details
  • Have an envelope area that does not differ by more than 10%
  • Include the same number of storeys
  • Have the same Design Air Permeability (Air Pressure Test Target)
  • Have a similar adjacency to unheated spaces such as garages, unheated stairwells etc.
  • Have a similar number of apertures and penetrations, for example doors, windows etc.

To help builders and developers, there are two building standards that provide in depth information in regards to air tightness testing, they are Building Regulation Part L and ATTMA TS1 & ATTMA TS2

What is my Designed Air Permeability Target?  

Building Regulations Part L1A and L2A are specially aimed at new buildings and most are now required to have an air-tightness test. Part L1B and L2B cover work to existing buildings and do not generally have a requirement for air-tightness testing.

All new dwellings are required to have a SAP (Standard Assessment Procedure) calculation prior to building control approval. It is ultimately the SAP calculation that determines the air permeability target needed to be achieved and whether it is a requirement.

All new non-dwellings are required to have a SBEM (Simplified Building Energy Model) calculation prior to building control permeability targets and will require testing.

The design stage SAP and/or SBEM assessments provide the required ‘air permeability rate’ you need to achieve on the project. Clients often mistake the maximum permissible air permeability rate of 10m3/hr/m2 as their target; however it’s the ‘designed air permeability rate’ which you need to adhere to, which is usually much lower than this at around 3m3/hr/m2 to 5m3/hr/m2. If your project is in London, the requirements are often more stringent. Most air tightness tests in London need to achieve 3m3/hr/m2.

We are here to help you with your

If you are unsure how many air tightness tests you require, please contact our friendly expert team for advice on helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

APT Sound Testing can assist you through the process and help you determine the specific air tightness testing requirements for your project. If you require more information please visit our website at

How to Pass an Air Tightness Test for Building Control Signoff

How to Pass an Air Tightness Test for Building Control Signoff

With the tightening of Building Regulations Part L later this year, it is now mandatory that air tightness testing is carried out to all new flats, houses and commercial buildings. Previously, it was possible to undertake testing to a just a sample of the units; however, this wasn’t deemed accurate and so the new regulations have been enforced. Another change to the building regulations Part L is the lowering of the maximum air leakage rate from 10m3/h. to 8m3/h, although it likely that you will need to achieve a much lower figure than this to comply with your deign state SAP Assessment.

Air Tightness Test

So accounting for the more stringent air tightness testing requirements, it is imperative that careful quality control is maintained at all times during the construction process, as this is the only way to ensure success of creating an airtight building and passing the air tightness testing at the first attempt avoiding costly remedial works and delays to the project handover.  

It’s worth remembering that with prefabricated buildings, an element of quality control is done in the factory by people who do know and build to an exacting standard within controlled factory conditions; however, on building sites there can be huge variables in regard to the quality of build, due to the quality of design, the fixing operatives and materials.

For Air tightness Consideration must be given to the following areas

There are literally hundreds of areas that need to be considered when creating an airtight building; however, the main are:

  1. The building fabric: the building fabric accounts for the walls, floor and roof. The type of build will dictate the amount of extra ‘onsite’ sealing works that may be required. For instance, it’s usually easier building with timber frame, than with masonry.
  2. Wall/floor/ceiling junctions: It is usually the wall/floor junction around skirting boards, and the wall/roof junctions by the eaves where the problems are usually worst.
  3. Doors and windows: doors and windows are often some of the worst areas of air leakage within a building fabric. Where the frame meets the wall reveal, is usually down to site detailing, but how the window or door closes against the frame is down to the window/door manufacturer and their installers. Sash windows or sliding patio doors can be susceptible to air leakage even if they are working properly. Twisted frames, missing seals and poorly (loosely) adjusted latches, are just a few issues that we find during smoke testing.
  4. M&E Service penetrations: service penetrations through the building envelope to allow for cables, pipes and ductwork are also a main area of air leakage. They’re not difficult to deal with if tackled at the right juncture i.e., before kitchen units are installed, and it is largely a matter of site supervision that they found and dealt with by a dedicated sealing team of an air tightness champion.
  5. Internal pocket doors – internal pocket doors, such as the type installed between living/dining rooms and bathrooms, can be a massive area of air leakage, so it’s really important that the builder builds an airtight pocket (sleeve) for the door prior to installing the running gear for the doors, and finally boxing out.
  6. Recessed ceiling lights – recessed ceiling lights in kitchens/living rooms etc. can also be large area of air leakage. In some large living areas, we have counted over 100 ceiling lights, with each light leaking the accumulated air loss can be huge. Many manufacturers provide airtight (fireproof) socks that go over the light housing (within the ceiling void) which can be an effective solution.
  7. Ceiling hatches – ceiling hatches, can also leak large amounts of air. Some manufactures offer proprietary door and frame systems, which are easier to install and will further reduce air leakage.
  8. Loft cupboards – the areas behind loft cupboards doors are often unsealed, sometimes there isn’t even flooring installed. it is essential that the walls ceiling and floors are completely finished, and the cupboard door are fully sealed with good quality seals.
Air Tightness Test

Can I lower my energy bills with an air tight home?  

Yes, it’s known that airtightness improves thermal efficiency and reduces heating costs in buildings. As a rule of thumb, if you lower your airtightness from 10m³/hr to 5m³/hr it will reduce your energy demand and heating costs cost by approx. 30-40%. With heating bills expected to hit around £2000 per year, that’s around a £700 annually, which is a huge saving, especially when you consider a dwelling air test is only £250!

At the start of your design and build process, your architect should be specifying what needs to be done in regard to air tightness, and the importance of having an air tightness champion on site to reduce the chance of an air tightness test failure.

We have put together our informative air tightness checklist – which should provide builders with helpful information on how to prepare dwellings for the air tightness test. often the best step is to ensure the contractor uses a project manager that has built at least one airtight house or building to a robust air tightness standard, and therefore has the knowledge and experience to manage and provide an air-tight building to achieve a precompletion air tightness test at the end of the project.

We can help you pass your air tightness test

By working with our customers throughout their design and construction stages, we can provide advice and guidance on the most feasible ways to avoid air leakage and pass your air tightness test.

At APT Sound Testing, we are happy to provide you with general air leakage design advice for your building envelope and onsite guidance. Upon completion of your project, we provide Nationwide UKAS Accredited Tightness Testing for domestic and commercial buildings to help you demonstrate Building Regulation Part L Compliance.

To find out more about our air tightness testing service or if you wish to discuss your project, please contact us by email at or visit our website.

Air Tightness Testing on all New Dwellings

Air Tightness Testing on all New Dwellings

Is Air Tightness Testing Mandatory on all New Dwellings?

Yes! From June 2022 all new builds need to demonstrate a minimum level of air permeability of 8m³/h.m²; however, this figure is often lower to align with the design stage SAP assessment. There won’t be an option to undertake ‘sample testing’ with the new Building Regulations Part L, it will be mandatory to undertake air testing to all dwellings on your project.

The final air permeability is done through an onsite, pre-completion air tightness test. The design air permeability for a particular building may need to be lower to achieve the overall carbon emission rate for the building via and/or within an employer’s requirements/specification.

Air Tightness Testing

Should I undertake sample air testing on a show home?

Its good practice to undertake an air test on a sample unit, such as show home/s – to check that they can pass the air test, as any problems identified during the test can be highlighted and addressed on future units. As show homes are often the first building to be completely finished it’s a good place to start. We often visit sites at the end of the project, where no thought has been given to air tightness which leads to unts failing the air testing, which leads to costly and disruptive remedial work.

Avoid Leaky Buildings

The quality of a buildings construction and design will have a major effect on the amount of air leakage through a building’s fabric. If a building is leaky, it can create a drawing effect, pulling air in through gaps in the ground floor and walls especially if the buildings is turned up high. This may result in cold untreated air being drawn into the home through gaps on the ground floor, walls and ceiling resulting in cold draughts. Treated ‘warm’ air leaking out through gaps in the dwelling’s fabric is one of the main causes of heat loss and wasted energy.

The main disadvantages of leaky dwellings are:

Damage to Building Fabric – Excessive air leakage can allow damp air to penetrate the building fabric, causing mould and the effectiveness of the insulation. It can also lead to an increase in dust and pollen.

Raised CO2 emissions – A leaky dwelling will result in higher emissions, if a house has an air leakage rate of 10m³/h.m², as opposed to 5m³/h.m² you may be losing over 1/3 of your heating into thin air.

Inadequate heating – The increased heat loss will mean that the correctly designed/sized heating system may not be able to attain the required temperatures. it also means that extra load will be placed on the heating system thus shortening the lifespan of the system.  

Discomfort – Excess draughts and localised cold spots can cause major discomfort. In extreme cases, excessive infiltration may make rooms uncomfortably cold during the winter months and too hot during the summer months, which often leads to complaints from residents.

Air Tightness Testing

The benefits of an airtight buildings

There are many benefits for lowering the air tightness rate in new and existing buildings, they are:

  • Lower energy costs for the lifetime of the building.
  • Less chance of ongoing damage due to the reduced risk of interstitial condensation within the building fabric.
  • Lower initial capital costs due to downsizing of plant and equipment required for heating/cooling.
  • A longer life cycle for the plant and equipment as it doesn’t need to work as hard to maintain target termperatures.
  • A safer building as fire compartments as well as external envelopes should be more robust.
  • The building environment should be less drafty and potentially warmer and/or cooler as required.
  • A raise in staff productivity – a happier worker is a usually  a more productive worker.

The most common air leakage paths

There can be literally hundreds of air leakage paths within the home which can lead to air test failures. however, in our experience (having undertaken thousands of air leakage tests) these are the most common problem Areas:

  • Floors – Unsealed wall/floor junctions can be a major area of air leakage. Also, services such as water pipes, gas pipes and electric cables that pass through external floor can also leak air.
  • External Walls – Air can escape through the external walls, around areas such as joists that are built into the wall, unfinished mortar joints, service pipes, water pipes, gas pipes, boiler flues and electric cables that pass through external walls. They are often hidden behind kitchen cupboards, bath panels, sink pedestals, toilet basins. Also, draughts in bathrooms are much more noticeable and are particularly uncomfortable for occupants.
  • Roof Spaces – Leakage into ceiling voids and the roof space. Air can leak past a poorly fitting loft hatch from the unheated roof void. Light fittings and gaps around them can offer a path into the roof void and also into the void between the ceiling and the next floor. Also, eaves cupboards can be a major area of air leakage as well as waste stacks and other service penetrations.
Air Tightness Testing

Where do I find more information on Air Tightness Testing?

There are many places to find information in regard to Air tightness testing. Basically the testing is carried out in accordance with the procedures detailed in ATTMA TSL1 (Please use the website   for a free download) and BS EN:13829 (2001). ATTMA TS1 describes how to carry out the air test and the analysis required to determine the air permeability of the building under test. Air permeability is expressed as volume flow per hour (m3/hr/m2) of air supplied to the space per square metre (m2) of envelope area for an internal to external pressure difference of 50 Pa.

Also, Building Regulations Part L also offers lots of useful information in regards  to Air Tightness Testing, such as which plots should be selected and what parts of the building can be temporally sealed etc.   If you would like more information on how to prepare your building to pass an air tightness test then please download our air tightness checklist.

A summary of our air tightness test procedure

Our air tightness testing procedure involves connecting a fan, or a number of fans, to a suitable aperture such as a standard external doorway in the building envelope. a number of environmental readings are taken (temperature and barometric pressure) and then the fan is turned on to pressurise the building over a range of pressure differences – usually between 25-70Pa, in 5Pa increments. Air volume flow rate through the fan (equal to the air leaking through the building envelope) and the pressure difference across the building envelope are recorded at each fan speed. In calculating air permeability rate, corrections are made for temperature and barometric pressure.

Please Contact us for your Air Tightness Testing now

It’s our ongoing aim to help all customers throughout their design, construction and final precompletion air tightness stages. We are happy to provide you with general air leakage design advice for your building envelope and onsite guidance. Upon completion of your project, we provide Nationwide UKAS Accredited Tightness Testing for domestic and commercial buildings to help you demonstrate Building Regulation Part L Compliance.

If you would like more information on our air tightness testing service, then please visit our website at or contact us at: To have a chat about your project please call:  01525 303905