Month: June 2023

Measuring the Air Tightness of Buildings

Measuring the Air Tightness of Buildings

In most cases a blower door system is used to measure the airtightness of residential and commercial buildings. The fan system can also be used to measure airflow between building zones, to test the air tightness of ductwork and plenums, and to help locate air leakage paths within the building envelope.

Air tightness testing is performed by a blower door system that measures the amount of air that escapes through gaps or air leakage paths throughout a building’s fabric. This is done by pressurising the building to 70Pa, using a blower door system, and measuring the pressure differences between the inside and outside of the building. Please see the video below that shows how an air tightness test is carried out.

It’s worth noting that an airtight building can help save energy by limiting the reliance on space heating and creating a more thermally efficient and draft free core. Airtightness is part of a fabric first approach to building designed to limit reliance on space heating and/or cooling and can save huge amounts of money over the building lifecycle.

Good Building Air Tightness Saves Money

So, we know an airtight building can help you save energy by improving thermal efficiency and reducing space heating costs; but by how much? As a rule of thumb, Improving, airtightness from 10m³/hr/m2 to 5m³/hr/m3 will reduce energy demand (and consequently cost) by approx. 22 per cent, this applies if everything else remains the same. So, an annual £2500 energy bill on a medium size dwelling could be lowered by as much as £550 per year; oh, and by the way the air tightness test costs approx. £300. Taking this into account, why wouldn’t you undertake an air tightness test when the payback is around 6 months.

When you look ay bigger building the savings could be huge. For instance, an existing Victorian school may very leaky, maybe above 15m3/hr/m2, if you are able to lower the air leakage rate to 5m3/hr/m2, then you may be able to lower your heating costs by 30%, that’s a lot for building that may use around £100K per year.

There are several ways to make your building more airtight. Some masonry, such as internal blockwork can be made airtight with the addition of a parging coat (a thin layer of mortar) or by the application of masonry paint, while monolithic systems such as insulating concrete formwork (ICF) perform well. Glazing is also airtight, so in most cases it’s the junctions between dissimilar materials that need to be focused on.


Optimising Your Building for Airtightness

The basic principle is to establish an air barrier line all the way around the building, including its walls, floors and roof. This is similar to the thermal envelope that is used to establish the boundary for insulation.

A holistic approach is required – in other words, every aspect of the house needs to be considered. The recommendation in Passive house guidelines is to draw a red line on the detailed plans to show where the barrier will lie.

This barrier line can be drawn either inside the structural members of the building or outside of it, but cannot be a mixture of both, as this introduces great complexity and is a recipe for failure.

The Most Common Air Leakage Paths in Buildings

there can be literally hundreds of possible air leakage paths in buildings; however, in our experience the most common areas are as follows:

  1. Gaps in and around suspended timber floors.
  2. Leaky ceiling lights in kitchens etc.
  3. Leaky windows or doors.
  4. Leaky pocket door (internal sliding doors)
  5. Pathways through floor/ceiling voids into cavity walls and then to/from the outside.
  6. Gaps around windows and doors.
  7. Gaps at the ceiling-to-wall joint at the eaves.
  8. Open chimneys and air bricks
  9. Gaps around loft hatches.
  10. Service penetrations through ceilings.
  11. Vents and waste stacks penetrating the ceiling/roof.
  12. Bathroom wall vent or extract fan.
  13. Kitchen wall extract fan and cooker extractor hood.
  14. Gaps around water and waste pipes.
  15. Boiler Flues.
  16. Service penetrations in air/ground source cupboards
  17. Gaps around kitchen waste pipes.
  18. Gaps behind the kitchen/utility units at the wall/floor junction – no skirting installed.
  19. Gaps around floor-to-wall joints (particularly with timber frame).
  20. Gaps in and around the tops of internal walls.
  21. Pipe penetrations in bathroom/shower rooms.

if a building fails the air tightness test, don’t panic! we use the latest smoke testing equipment to located the air leakage paths so they can be sealed by your site teams.


Our Air Tightness Testing Services Include:

  • Commercial air tightness testing to large buildings
  • Residential air tightness testing
  • Passive House testing
  • Smoke leakage surveys with defect reports
  • Air testing to raised floors
  • Air testing to plenums
  • Air testing to hospital isolation suites
  • Air testing (integrity testing) to rooms protected with fire suppressant systems
  • Air testing to clean rooms

We can undertake your air tightness test

Contact us today to learn more about our air tightness testing services and how we can help you achieve a sound test pass in compliance with Part L of Building Regulations.

For more information, please contact us at: or visit us at

Finding Building Defects with Thermal Imaging Surveys 

Finding Building Defects with Thermal Imaging Surveys 

Thermal imaging surveys are a great tool for identifying building defects in new or existing commercial building. They can pick issues within your building envelope, such as damaged or missing insulation,

Thermal imaging inspections are useful for spotting leaks in pipes, and detecting moisture damage such as dampness in floors walls, and ceilings, and is often instructed by insurance companies to determine whether there are any hidden dangers in buildings that could cause major damage such as old electrical and mechanical systems.


Common building defects found with thermal imaging surveys

There are literally hundreds of varying defects that can be found using thermal imaging inspections, here is a list of the most common issues found in residential and commercial buildings:

  • Faulty Electrical Systems – thermal imaging is good for fault diagnosis in electrical systems. Components can be checked in a live state with little danger to the user, there is no effect on the components or interruption in any processes the electrical system may be controlled, thus no downtime for server rooms and/or manufacturing plant etc.
  • Leaky Pipes – leaking pipes in walls, floors and ceilings allow you to quickly target and rectify the issue before it causes too much damage to your building
  • Building Construction Defects – thermal Imaging surveys can identify construction faults such as damaged or missing insulation in cladding and/or cavity walls.
  • Air Leakage Paths – Identifying air leak paths in your building fabric during your building survey can help you keep your building warmer and more insulated, often resulting in decreased energy costs.
  • Moisture Issues – Thermography can help identify moisture problems on the interior or exterior of the property which can affect the drying of buildings.
  • Flat Roof Leaks – Thermal Surveys can help reduce the chance of possible leakage in flat roofing before it becomes a wider issue.
  • Damp Issues – Using thermal cameras, you are able to accurately identify areas of damp, allowing you to target and rectify the issue from its root cause.
  • Building Renovations – Thermal Imaging can help identify which parts of a building need improving, saving time and money on unnecessary restoration works.
  • Leaking Pipes – thermal imaging can help you identify locations of leaking pipes in walls, floors and ceilings allowing you to quickly target and rectify the issue before it causes too much damage to your building.

We provide high-quality Thermal Imaging Inspections


Our experienced and highly qualified thermal imaging surveyors produce higher quality and more technically consistent thermography inspections. Our Level 3 engineers can troubleshoot, calibrate equipment, interpret data, and create reports that are both informative and easy to follow.

When you are employing a thermographer, you should check to see that they incorporate the high specifications possible for their inspections. Are they certified to Level 3 and do they use large format thermal imaging cameras?

If you would like further information on out thermal imaging inspection services, please contact us at 01525 303905 are or or visit our website at and download our thermal imaging checklist

Acoustic Design Service

Acoustic Design Service

APT Acoustic Design Service
The importance of good acoustic design and construction should not be underestimated. If a project fails its precompletion sound testing it may need costly remedial works to comply with Building Regulations Part E.

On new build developments we offer comprehensive acoustic design via coordination with the lead consultant. We can also visit site during the construction process to undertake a detailed site survey visit to check the onsite construction is as per the construction details – this is often good to ensure the relevant parties are fully aware of the installation detail required, which in turn may highlight possible ‘onsite’ construction problems.

Acoustic Design Service in London

On conversion projects we can visit site and undertake sample sound testing, this will evaluate the performance of the existing floor and wall partitions, which allows for targeted acoustic design as the acoustic performance of the dividing partitions may be already good – especially if the buildings floors are constructed out of cast in situ concrete.

APT Sound Testing provides a consultancy design service to Architects, Property Developers and Building Contractors. We specialise in helping small developers pass their sound testing to achieve Part E compliance for all types of project such as new build properties, blocks of flats and conversions.

Many of our clients have previously conveyed negative feedback that larger acoustic consultancies don’t understand small builder requirements and subsequently often produce complicated acoustic design detailing that are both difficult (in terms of build-ability) and very costly to undertake. We try to provide acoustic solutions that are cost effective and easy to construct, saving our clients time and money.

If you would like more information in regards to our acoustic design service and/or sound testing please contact us at 01525 303905 or visit our website at:

APT Sound Testing Services

APT Sound Testing Services

APT Sound Testing Services
Here at APT Sound Testing we undertake sound testing on all types of residential buildings and commercial buildings. We also undertake sound testing on schools and buildings containing rooms for residential purposes.

We provide provide UKAS accredited sound testing for London and the whole of the UK as required by Approved Document E of the Building Regulations.

Experienced Sound Testing Engineers

The team of experienced sound test engineers at APT Sound Testing are dedicated to giving our customers the best quality of service and offer acoustic design advice where possible, to help our clients achieve the required acoustic results to pass the sound testing and attain building completion.

We can also undertake ‘in house’ UKAS accredited air tightness testing in one seamless package, lowering costs and negating coordination issues.

Who We Work With

APT Sound Testing 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.

We have one of the highest return-client rates of any precompletion testing and consultancy services within the United Kingdom. This is due to the proactive unique service that we can provide. We do not subcontract our work – everything is undertaken in-house.

We are one of the few companies that have an office in central London, which means we can respond quickly and efficiently to our client’s survey and testing requirements. We also have the resources to undertake last minute testing have the resource capabilities to carry our last minute testing and weekend working – which we often do in the banking sector) should it be required.

Thanks to highly trained engineers, we are able to provide a quick and efficient service with the emphasis on customer satisfaction, which is why we have one of highest return-client rates of any acoustic consultancy. Using our many years’ acoustic design experience has allowed us to build a knowledge base that helps us achieve an understanding of our client and project requirements. We are also a multi UKAS accredited laboratory, working to strict ISO standards so you can sure of a quality service from start to project completion.

In is our ongoing policy to listen to our clients’ needs and present them with practical, cost-effective solutions which also takes into account buildability considerations. This means that we offer acoustic consultancy solutions, which encompasses acoustic design and precompletion testing in one easy package.

We use the latest acoustic testing and survey equipment which is UKAS calibrated to the highest standards. By investing in both our personnel and equipment it allows us to offer a more efficient service.

APT Sound Testing strive to provide our clients with a guaranteed quality service every time they decide to get in touch.

The team at APT Sound Testing would love to hear about your latest project, so please get in touch now by calling 01525 303 905 or visit our website today.

Sound Testing for Leasehold Agreements

Sound Testing for Leasehold Agreements

Sound Testing for Leasehold Agreements
One of the main reasons for neighbour disputes is down to the fact that floor modifications may have taken place without the flat owner, first consulting his/her leasehold agreement. In many cases the lease agreement contains something similar to the following conditions:

‘If the tenant wants to change the floor construction within his dwelling he shall’:

Commission an independent acoustic consultant to carry out a pre installation test, design the new acoustic installation and carry out a post installation test and provide the results to the landlord’s surveyors for approval; and invite the Landlord’s surveyor to inspect the acoustic insulation before it is concealed; and accept that the Landlord.

Whilst granting this Licence, does not accept any responsibility for the design or performance of the insulation provided and that if any issues arise the Tenant will address these immediately. In the event of reasonable complaint being upheld by the Landlord or his agent concerning noise affecting other Tenants within The Building, the Tenant will arrange for carpeting (the provision of which shall be determined by the Landlord) to be positioned and maintained at the Tenant’s sole cost;

We offer a comprehensive acoustic service to let our clients comply with their leasehold agreements.

Pre-works Sound Testing of the existing construction. This offers an accurate overview of the acoustic performance of the existing floor partition/s prior to the commencement of construction works.

It also enables us to offer a targeted acoustic design using the sound insulation performance of the existing construction.

Acoustic design review – once we have the performance figures from the sample sound testing have been established, we can forward a design that should improve the performance of the existing floor partition – even if you are changing the floor from a carpet to engineered timber floor finish!

Site Survey Visit – This allows us to check that the installation team is installing the acoustic materials as per manufacturer’s guidelines.

Final Precompletion Sound Testing in-line with Approved Document E. This provides an accurate overview of the acoustic performance of the upgraded partition/s, the results of which can be handed over to the relevant person for sign off.

Having undertaken hundreds of sound tests across London and the South East, we know the importance of getting acoustic design right from the word go, is key, and APT Sound Testing can help in all areas of sound insulation design and sound testing. Please get in touch with us today to request a quote or call us on 01525 303905 to discuss your development. Alternatively, visit our website for more information.

Please Note: Although we take every care to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgment. It is the responsibility of the duty-holder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.

BREEAM Thermography Surveys in London

BREEAM Thermography Surveys in London

Undertaking a thermographic survey can be one of the easiest and cost-effective ways to generate BREEAM credits. Thermographic surveys are now a feature of BREEAM the environmental assessment method and rating system for commercial and domestic buildings. We always work proactively with clients to ensure a successful outcome.

BREEAM Thermography Surveys in London

BREEAM New Construction and BREEAM 2012 Domestic Refurbishment award credits for thermography surveys carried out by a Level 2 certified thermography engineer. The way each scheme works with respect to awarding points for thermography is slightly different. The very latest BREEAM 2014 UK New Construction scheme provides BREEAM credits for thermographic surveys but is in a slightly different way. A quick summary is below:

BREEAM Technical Guide
This new BREEAM technical guide describes an environmental performance standard against which new, non-domestic buildings in the UK can be assessed, rated, and certified. You can gain 1 BREEAM credit for a BREEAM thermographic survey in London. Within Man 01 – Sustainable Procurement, it states the following:

This new BREEAM technical guide describes an environmental performance standard against which new, non-domestic buildings in the UK can be assessed, rated, and certified. You can gain 1 BREEAM credit for a BREEAM thermographic survey in London. Within Man 01 – Sustainable Procurement, it states the following:

>>> The main contractor accounts for a thermographic survey within the project budget and programme of work.
>>> Once construction is complete a thermographic survey of the building fabric is undertaken in accordance with the appropriate standard and by a professional holding a minimum Level 2 certificate in thermography.

The survey confirms:
Continuity of insulation in accordance with the construction drawings
Avoidance of excessive thermal bridging
Avoidance of air leakage paths through the fabric (except through intentional openings)
Any defects identified via the post-construction inspections are rectified

We use the latest high-resolution thermal imaging cameras to undertake our Thermographic Surveys throughout London and the Southeast. Thermal imaging is one the quickest and easiest ways to undertake fault diagnosis on your buildings, as thermography can quickly and accurately identify building faults and an easy to follow reports, so the defects can be quickly indented and rectified by the contractors.

When you are employing a thermographer, you should check to see that they incorporate the high specifications possible for their inspections. Are they certified to Level 3 and do they use large format FLIR thermal imaging cameras?

Their specification should include:

>>> Level 3 thermographic certification
>>> Level 3 qualified thermographers
>>> Large format FLIR cameras with 45-degree lenses

The benefits of thermographic inspections are well documented and when it’s used in conjunction with air tightness testing it can be a very power combination – especially when its used on commercial buildings.

We hope this information on thermal imaging inspections has been helpful. If you require a Thermal imaging survey our professional and certified Level 3 Thermographer’s will carry out your thermographic Inspections for BREEAM compliance in accordance with all necessary standards and current regulations.

All we need are a few details such as floor plans and elevation drawings and the building location to provide a quotation. We will also send our informative checklist to help you prepare for the thermal survey.

Please contact us for more information on our thermographic inspection services. If you would like to contact us for more information on our thermal imaging services, please contact us on 01525 303905 or by visiting our website.

How Many Sound Tests Do I Need On My Project

How Many Sound Tests Do I Need On My Project

How Many Sound Tests Do I Need On My Project?
Our clients often ask ‘how many sound tests do I need on my project’. Part E stipulated that one set of sound tests needs to be undertaken for every ten flats or houses, provided the construction system is the same.

A set means that the test should include two locations where the party element (wall or floor) is tested. This is equivalent to two individual tests when assessing the performance of a wall this means 2 airborne wall, 2 airborne floor and 2 impact sound tests as a minimum wherever possible. All tests must be undertaken between habitable spaces (e.g. bedrooms, living rooms) and not to or from common spaces such as stairwells and corridors.

sound tests

Acoustic Design Advice

Approved Document E 2003 also states that a minimum of 10% of all party walls and floors is sound tested for every type of construction or sub-group, this means where there a variations in the construction of the floors and/or walls may occur then further testing may be required. The amount of sound tests required for each type of development is:


On houses two airborne sound insulation tests on a pair of separating walls would be required.


On flats a 6 Pack would normally be required, this would usually comprise of two airborne sound insulation tests on separating walls; two airborne sound insulation tests of separating floors and two impact sound transmission tests of separating floors

Rooms for Residential Purposes:

On student accommodation, hotel rooms & care homes a set of tests would usually comprise of one airborne sound insulation test of a separating wall; one airborne sound insulation test on a separating floor and one impact sound transmission test of a separating floor.

If you are unsure of the amount of sound tests required on your development, please contact us now by visiting our website or calling our support team at 01525 303905.

Sound Testing In London

Sound Testing In London

APT Sound Testing has been helping our clients with acoustic design on their projects for almost 15 years and sound insulation testing for almost 20 years. During this time we have gained a massive amount of experience in dealing with building acoustics on all types of new build and conversion projects throughout London and the South East. That’s why so many clients use us for their acoustic design and sound testing in London.

Sound Testing In London

UKAS Accredited Sound Testing
Our combined acoustic design and sound testing package is one of our most popular packages, as it reduces the chance of clients failing their precompletion sound testing. We offer acoustic advice from the design stage of your project, right through to helping clients that have already failed their sound testing.

We can offer easy-to-implement acoustic upgrades to ensure our clients pass their sound testing at the second attempt. Unfortunately, many sound testing companies do not offer acoustic advice in the event of a failure, so it would be worth checking this with the company prior to placing an order to proceed with the work.

APT Sound Testing’s quick and professional service ensures that you won’t have to wait too long for your acoustic design report and/or the sound test certificate. As we use the latest Norsonic sound testing equipment we are able to offer verbal results immediately on-site, along with a full written report and your certificate the very next day.

APT Sound Testing has been in the industry for a long time and we know the importance of your project passing the sound testing to achieve building sign-off, as it’s usually one of the last items you need to undertake prior to building handover.

We are a UKAS Accredited Company

Our sound test engineers carry all the latest Norsonic equipment, which is class one rating, and all of our acoustic testing/sound testing, is completed to a strict quality controlled standard. We provide full UKAS Accredited sound testing.

To find out more about our acoustic design service and/or UKAS-accredited sound insulation testing in London, please visit our website at, alternatively please email us at or call us on 01525 303905 to discuss your needs with one of the team.