Month: March 2022

Thermal Imaging Surveys

Thermal Imaging Surveys

APT Sound Testing provide UKAS accredited sound testing & Thermal Imaging Surveys for London and the whole of the UK as required by Approved Document E of the Building Regulations. We undertake projects on all types of residential buildings and commercial buildings. We also undertake sound testing on schools and buildings containing rooms for residential purposes.

Thermal Imaging Surveys in London

A thermal Imaging survey is a completely non-invasive method of investigating many aspects of a building that are virtually impossible by any other method.

Thermal Imaging Process

A thermal Imaging survey is an extraordinary method of investigating many aspects of a building that is completely non-invasive.

Thermal Imaging Inspections use IR Thermography to identify a wide range of issues such as:

• Incorrectly applied or inadequate insulation within the building envelope

• Locating air leakage paths into/out of your building

• Moisture infiltration

• Poor moisture barriers

There is no other low impact and accurate way to assess the unseen performance of insulation or the building fabric.

A thermal Imaging Survey can is also ideal for identifying water penetration through roofs or other parts of a building structure, alleviating the need for time consuming water dye tests which are not always accurate.

APT Sound Testing uses the latest Flir Thermal Imaging Cameras for our thermography report generation and as well as utilising the latest software for accurate reportage and trend analysis.

This means or thermal imaging reports can be issued within hours of the survey being completed with recommendations to help our clients deal with every eventuality.

How we Prepare for a Thermographic Survey

What is also important is that there must be no direct or residual solar loading from the sun in the building.

Many companies have their thermal imaging surveys undertaken an hour or so after sunset and this is usually flawed and may lead to inaccurate results. Whilst there may be rate exceptions to this, as a rule, there will be solar load in the building for many hours after sunset.

Therefore, we have learnt to undertake more accurate reportage the thermal imaging surveys should generally be conducted in the early hours of a cold morning, approx.

Two hours before the sun can fall on the building. It is more difficult to undertake conduct these types of heat loss survey during summer months when the ground temperatures and surrounding buildings are at high temperatures for months on end; however, this can be overcome by ramping up internal temperatures within the building and using the latest and more advanced thermal imaging cameras.

In all cases APT Sound Testing will check each project in isolation to ensure the correct site conditions are in place prior to undertaking the thermal imaging survey in compliance with the requirements with BS EN 13187. Building Regulations Part L and this link both offer lots of useful information in regards to Thermography Surveys.

We have years of experience working with a wide range of clients that span both the public and private sectors. We have clients ranging from self-builders through to the largest housing developers. We also work with the health authority and the banking sector on their cleanroom testing. Our clients have benefited from our wealth of knowledge and friendly, proactive service that we provide.

If you need more information on how to prepare your building for a Thermal Imaging Survey please download our air tightness testing checklist. If you would like more information in regards to our, please visit our website or call us Direct on 01525 303 905

Improving Acoustics in Dwellings

Improving Acoustics in Dwellings

When designing a new project containing multiple dwellings, why go further than just meeting the basic regulations. For instance, if you only manage to achieve the minimum requirements for compliance with Building Regulations Part E for sound testing, then the chance of noise complaints will usually be higher than if you better it by 5-7dB.  

Improving Acoustics in Dwellings

Improving Acoustics in Dwellings

The World Health Organisation defines noise as ‘unwanted sound’ and such noise in buildings can have significant effects on the people (residents) who occupy them. If a person is subjected to excess noise for long periods, it can result in physical discomfort or mental distress and in many cases noise complaints. The WHO estimates that around 50% of the population of the European Union live in areas are exposed to noise levels that do not ensure acoustic comfort to their inhabitants and more than 30% are exposed to noise levels at night which is at a level disturbing to sleep this is simply not good enough.

Within homes, a noisy neighbour can be one of the main problems experienced in attached housing. It’s estimated that up to 4 million people in Britain have had their lives disturbed by noisy neighbours.

The best way to combat excess noise is to ensure that proper precautions are taken at the design stage of the project and thereafter during construction of the building. Noise transmission levels should be compatible with the building’s usage with the correct acoustic climate provided in each space.

The UK has the building regulations and a number of sector specific guidance documents covering noise, these are:

  • Approved Document E
  • Building Bulletin 93
  • Health Technical Memorandum 08-01
  • BS8233
  • BS4142

There are strong arguments for considering solutions which go above and beyond just meeting the minimum requirements in the above regulations. For instance using acoustic ceiling products and partition systems it is possible to create environments that offer greater acoustic comfort for occupants go above and beyond the standard Building Regulations requirements, which should have a positive impact on health, well-being and productivity.

Firstly, get advice on acoustic design before starting construction. The most effective way to ensure you improve the acoustics on your project and pass your sound test at the first attempt is to plan your project with sound insulation in mind. This does not need to be costly, and can save considerable time and cost at the end of the project, by reducing the chance of needing to undertake remedial works and re-testing.

The two main areas to take into consideration are usually the dividing wall and floor partitions. If you are unsure of how to build the separating wall and floor partitions and associated junctions across your project don’t panic, we can offer an acoustic design service. The degree of guidance you require can vary from site to site; however, we can cater for every eventuality by offering sample sound testing to establish the sound insulation performance of your existing wall and floors. Thereafter we can undertake more targeted design review using the information at hand.

When your project is underway, we can visit site and check the construction is being constructed as designed. Even minor alterations can have a significant impact on the effectiveness of your sound insulation measures.

If you have a new project and you need help with your acoustic design and/or sound testing then please email us at:  or call us on 01525 303 905. If you want more information on our full range of services please visit our website at:

If you would like to download more information on Improving Acoustics in Dwellings and how to prepare for your sound testing, please click download our sound testing checklist.

Improving your Air Test with Good Construction

Improving your Air Test with Good Construction

Improving your Air Test with Good Construction Detailing

Since April 2006, air testing has been required to be tested for Air Permeability, in order to comply with Part L1 & L2 of the Building Regulations.  Since 2011 the air leakage target has reduced from 10m3/hr/m2 to 5m3/hr/m2. In the next 2 years it is expected that the target may be reduced to 3m3/hr/m2.

We provide a personal, helpful, efficient and cost effective air test service to our clients. Using the latest high power, portable door fans systems, we offer air testing to all building types, ranging from small rooms, flats & houses to office blocks & large distribution warehouses in accordance with the Building Regulations Part L1 & L2

What is an Air Tightness Test?

Our air test fan systems are compact, discreet and fit simply into a personnel door. The system can easily be transported through areas of limited access or up to high level areas. Many contractors use us to undertake the testing in busy city centres or other tight access areas as we eliminate the site disruption caused by the larger trailer type air testing equipment.

In the event of a building failing an air test we then offer smoke testing – both hand-puffer for dwellings and large scale smoke testing for commercial buildings. This highlights the areas of air leakage through the building fabric. We can then undertake a full written and photographic survey as reference for your site management and relevant subcontractors. We will also offer FREE advice on the best method to seal any leaking areas. The main benefits of this are:

•             Air leakage paths are quickly identified in the event of a test failure

•             A full written air leakage report is forwarded so remedial works can start straight away

•             Building handover/practical completion and handover can be achieved more quickly

Construction Phase Consultancy

Air Pressure Testing has a practical ‘hands on’ approach during building construction and prefers to be involved as practically possible during this stage. We undertake periodic site visits to inspect the building envelope assembly as it is constructed and provide both written and photographic reports to enable any further works / remedial works deemed necessary to be accurately targeted. Site visits are generally to allow us to identify:

•             Insulation placement, continuity and effectiveness at thermal bridge junctions

•             Air barrier continuity within elements and at interfaces (particularly at sub-contract  package interfaces) 

Foundation/ground floor Initial works (Air Test risk factor 8)

a.            Ensure that any penetrations through the air barrier (e.g. service pipes) have been dressed. Pre- formed collars, sometimes referred to as ‘top hats’, which seal to the membrane and around the throat of the pipes are effective means of achieving a good airtightness seal.

b.            Ensure that the wall and floor damp-proof course/membrane forms an adequate airtight layer.

c.             With using timber frame construction, check that the sole plate is sealed to the foundation/floor-slab.

Internal Floors (Air Test risk factor 9)

a.            Using joist hangers can limit penetrations through the air barrier.

b.            If joists are to be supported by the wall, check that there is no air leakage into the cavity and the wall between the joists is fully filled/completed.

c.             Ensure timber floor sheets/boards are well fitted and sealed at their edges as well as at junctions with perimeter walls with mastic.

d.            Ensure the ceiling-to-wall joint has been sealed with mastic.

Eaves Level (Air Test risk factor 8)

a.            Ensure the airtightness layer between the wall and ceiling/roof is continuous ceiling below the roof space.

b.            Ensure there is a continuous air barrier over the whole ceiling area.

c.             Ensure all service penetrations (ventilation ducts from extract fans and light fittings) have been properly sealed where they penetrate the air barrier as this is a major air leakage path.

d.            Ensure all loft hatches are airtight and surrounds are sealed where they penetrate the air barrier.

External Doors & Windows (Air Test risk factor 7)

a.            Ensure you always specify good quality windows and doors.

b.            Always check that the wall-to-frame junction is properly sealed and continuous with mastic against the wall’s airtightness layer

c.             Ensure all windows and doors have an appropriate weather-seal between the opening unit and the frame – check for missing weather seals.

d.            All external doors should be fitted with draught excluders.

e.            Ensure the letterbox is fitted with a draught excluder.

Envelope Service penetrations (Air Test risk factor 10)

a.            Check for seals at service entry points (pipe and cable routes), e.g. around incoming water pipes,  gas pipes, electrical cabling, as well as waste water pipes for sinks, baths, washing machines,  dishwashers, etc. Seals should be provided internally and externally.

b.            Where multiple services penetrate at the same point, there should be sufficient space to fully seal round each of them.

Brick/block masonry construction (Air Test risk factor 7)

a.            Ensure the quality of construction as the work proceeds. Good mortar joints are required (i.e. no gaps around the blocks or bricks) on both internal and external faces – this also reduces sound transmission.

b.            Ensure all block-work is paint grade and painted were possible.

c.             The application of wet plastering, parging or the addition of fully-sealed dry lining will create a good air seal.

d.            Parging is an effective method of sealing around joists that penetrate the inner leaf of an external wall.

e.            Check that there is a good seal around all services that penetrate the masonry.

Plasterboard Dry lining (Air Test risk factor 10)

a.            Check the plasterboard is continuous (e.g. there are no large holes behind the kitchen units/bath). 

b.            Ensure that airtightness measures have been incorporated at all edges, particularly at the floor/ceiling junctions and around openings.

c.             Check the plasterboard is correctly detailed at joints, corners, reveals and window sills. Plasterboard should be mounted on ribbons of plaster or adhesive around all the edges (rather than dabs) to  prevent air leaking through the porous block-work behind.

Sealed Membranes & Vapour barriers (Air Test risk factor 9)

a.            Where the vapour barriers have been used as the air tight barrier, check that it is complete, that all joints have been sealed and it’s not damaged.

 Timber frame construction (Air Test risk factor 8)

a.            It’s usually easier to make timber frame dwelling airtight than other forms of construction. This is partly due to pre-fabricated construction and the use of the impermeable vapour barrier as the air barrier. The plasterboard layer can also become an air tight layer.

b.            Where vapour barriers have been used special care will be needed to avoid it being torn. Any damage to the vapour barrier must be carefully repaired.

Remedial Air Sealing Solution

1.            Smoke Investigation with Air Testing Fans:

APT’s Air Sealing Team utilise smoke investigation to identify the air leakage paths and prioritise which can be sealed first to attain an air test pass.

2.            Remedial Air Sealing Works:

APT can carry out the air sealing works. Typically allow for a 2-4 man Remedial Air Sealing Team. Adequate access must be provided for all sealing works. We provide all air sealing Materials – Rates provided on Request.

3.            On-going Air Tightness Assessments:

Enables the APT Sealing Team to seal the building until the fans indicate that the air

test would pass – thereby minimising the remedial works and time on site.

4.            Final Air Test:

APT’s Air Test Technician carries out a final independent test for compliance.

Whether you need a full on-going air tightness design/consultancy service, or just a simple air test, Air Pressure Testing have the knowledge and experience to ensure your building passes first time.

If you are unsure of the air tightness services you require, please visit our website, or call us on 01525 303905 and one of our Air Tightness Consultants will guide you through the process, ensuring that you receive the right level of advice at the right time.

Air Tightness Testing & Smoke Surveys

Air Tightness Testing & Smoke Surveys

Air Tightness Testing & Smoke Surveys to Fix Leaky Buildings

This article explains the use of combined air tightness testing and smoke surveys to evaluate and fix air leakage paths in houses and commercial buildings. On past projects where we have encountered very ‘leaky’ buildings, we have managed to lower air leakage rates from 40m3/hr/m2, down to a respectable 5m3/hr/m2. All this was accomplished using our combined air tightness and smoke testing survey service to identify the air leakage paths for our client’s air sealing teams.

Energy specialists have known for many years that that excess air leakage can accounts for between a third and half of a typical home’s heat loss. Yet it’s often quite difficult to pinpoint air leakage and heat loss in both new building and conversion projects.

Air Tightness Testing

The beauty of combined air tightness and smoke testing is it provides an accurate and visual approach to identifying and controlling air leakage in in buildings. Blower doors equipment can be set up quite quickly and the test and smoke survey can be carried out in a matter of minutes, meaning that you can quickly and ascertain the buildings air leakage rate as well as receiving a comprehensive air leakage survey report, highlighting the air leakage paths within the building, so targeting sealing works can be undertaken by the contractor/builder at a later date.

Also, its worth noting that different types of buildings require different levels of air tightness. Air-conditioned buildings should be tighter than naturally ventilated ones with air leakage targets less than 3m3/hr/m2. Cold storage, laboratories, isolation suites and archives facilities can be between 0.2 to 2.0m3/hr/m2, so are designed to be much more air-tight to ensure humidity, heat loss and the ingress of pollutants help to a minimum and within specification.

What is blower door smoke survey?

Our blower door fan mounts into a door-sized housing, that can be adjusted to suit the size of the door frame.

We then set up the blower door equipment as follows.

  1. We’ll temporarily install a blower door fan system (depending on building size) in a suitably placed doorway.
  2. We then take a series of environmental measurements such as internal and external temperatures as well as barometric pressures.
  3. We then turn on the fan equipment and take measurements between 25-70Pa in 5Pa increments, recording the pressure differential at each step.
  4. Finally, our technicians will calculate the total air flow required to achieve a pressure differential of 50 Pa, divided by the total building envelope area – this calculation will show leakage rate in m³/h.m² @ 50 Pa.
  5. Once the building air leakage rate has been established, we then pressurise the building (blows air into) to around 50 pascals of pressure. This forces air to flow through cracks or air leakage paths throughout the building envelope.
  6. We then turn on the smoke machine and walk around the house highlighting and recording all the air leakage paths through the building envelope.

We usually allow two to three hours to complete each air tightness smoke test; however, we can attend site all day if instructed. This allows your operatives to seal all the necessary air leakage paths on the day of the test. If you are planning on undertaking remedial sealing works on the day of the test, your operatives will need to have mastic, expanding foam, draught excluders, plasterboard, grip fill and suitable safe access to undertake the sealing works.

If some of the areas are difficult to reach such as very tall commercial buildings, we can also undertake a Thermography survey. This is performed using an infra-red camera to identify hot and cold spots on the surface of the building; this requires a temperature variation and is often done at night.

What is Equivalent Leakage Area (ELA) when trying to understand air leakage in buildings

Our equipment and software compare the air blown through the fan to the pressure drop across the blower door equipment. This gives then produces the relative tightness result for the house. Our computer software then converts the pressure drop to an equivalent leakage area (ELA), which is the overall size of a single hole in the building fabric that would equate to the same amount of air leakage.

The equivalent leakage area (ELA) is very useful for our engineers and clients to understand the cumulative effect of the many small leaks – such as leakage along a skirting board – that are present within a typical building as they may add up to the equivalent of an open door or window on the building.

What types of Smoke machine do you use?  

When it comes to smoke test surveys, we use 3 different types of smoke machines.  We have a smaller handheld smoke machine for standard houses. We then have our middle size smoke machine which uses pressurised smoke canisters, which is extremely useful for large houses and smaller commercial buildings and smoke shafts etc. we then have our large smoke machines that fill a large commercial building in minutes.

So, to recap, we use the different size smoke machines on the following buildings:

  • Small smoke machine – houses, flats, and laboratories
  • Mid-size smoke machine – small commercial buildings and smoke shafts
  • Large smoke machine – large commercial buildings

In all instances, we always use our smoke machines with our blower door systems to accurately identify the air leakage paths in buildings. Without the inclusion of a blower door system to pressurise the entire building, you will only see small amounts of ‘wispy’ smoke drift, which makes it very difficult to identify and record the exact air leakage areas.  

Air Tightness Testing & Smoke Surveys

Air Leakage Paths found During Previous Smoke Test Surveys

  1. Poorly installed windows and doors which do not close tightly
  2. Windows and doors with missing seals
  3. The gap at the wall/skirting board junction.
  4. Perimeter and internal wall/floor junctions.
  5. Gaps around service penetrations (such as water and electrical) through floor and walls
  6. Pathways through ceiling voids into masonry cavity walls
  7. Pathways through eaves in cavities
  8. Gaps around windowsills and door reveals
  9. Gaps around bathroom and WC services
  10. Gaps around kitchen and utility services.
  11. Gaps between dry lining and ceilings
  12. Unsealed chimneys
  13. Gaps around electrical and IT fittings
  14. Gaps around ceiling loft hatches
  15. Ventilation penetrations through the walls, ceiling, and roof
  16. Poorly installed extractor fans to kitchens, utility, and bathrooms


How We Can Help

At APT Sound Testing we have large amount of experience in understanding the requirements of Approved Document L, along with extensive experience of carrying out thousands of successful air tightness tests on a wide range of developments across London and the UK.

In order to achieve the required air tightness target (which is getting lower all the time) and to avoid the risk of a failed air tightness test, we strongly recommend that early consideration is given to the design of the air leakage line within your project.

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 attain compliance for the air tightness test. Please download our air tightness checklist to help you prepare for your 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 on 01525 303905 or email us at