Professional Air Tightness Testing in the UK

Professional Air Tightness Testing Across the UK

At APT Sound Testing, we specialise in professional Air Tightness Testing services across the United Kingdom, supporting projects of all sizes—from single residential homes to large commercial developments. Our experienced team works closely with developers, contractors, and property owners to ensure buildings meet performance standards and comply fully with UK Building Regulations.

What sets us apart is our UKAS accreditation, allowing us to carry out both Air and Sound Testing to the highest industry standards. Because our engineers are multi-skilled and fully accredited, we can also perform Air, Sound, and Ventilation Testing during a single visit. This integrated approach saves time, reduces costs, and streamlines on-site coordination. Unlike many providers, all our testing is carried out in-house by our own engineers—we never subcontract.

Why Air Tightness Testing Is Essential

Air tightness testing became a legal requirement in 2006 in England and Wales under Building Regulations Part L, which focuses on the conservation of fuel and power. Its purpose is to create energy-efficient buildings by reducing uncontrolled air leakage—something most people recognise as draughts.

Benefits of Reducing Air Leakage

Sealing gaps, cracks, and joints in a building’s fabric helps to:

• Improve energy efficiency

• Reduce carbon emissions

• Lower heating and cooling costs

• Enhance indoor comfort

Energy lost through air leakage contributes to the Building Emission Rate (BER). To comply with regulations, new developments must meet specific air leakage targets:

• Standard dwellings: ~5.0 m³/hr/m²

• Commercial buildings: 3.0 m³/hr/m² or lower

The Consequences of Poor Air Tightness

Air infiltration and exfiltration happen simultaneously. If air enters in one spot, it must exit elsewhere. Poor air tightness can cause:

1. Increased Energy Loss
   Escaping air is replaced by conditioned air, increasing energy use and costs.

2. Condensation and Moisture Problems
   Warm air escaping into colder wall cavities can cause:

   • Mould growth

   • Rot

   • Structural damage

   • Poor indoor air quality

3. Discomfort for Occupants
   Draughts can make spaces uncomfortable, or even unusable. For instance, we once tested an office building with a leakage rate of 25 m³/hr/m², causing staff to refuse to work. After sealing the leaks, the building achieved below 5 m³/hr/m², restoring comfort.

4. Pollution Ingress
   Excessive leaks can pull polluted air from nearby roads, fuel stations, restaurants, or waste areas into the building. A well-sealed building improves indoor air quality and safety.

Our Air Tightness Testing Process

At APT Sound Testing, we use professional blower door equipment to measure air leakage precisely.

Step 1: Install the Blower Door System
The fan system is fitted securely into a standard door opening (approx. 900mm x 2000mm).

Step 2: Record Environmental Conditions
We measure internal and external temperatures, barometric pressure, and ambient conditions before testing.

Step 3: Pressure Testing
The fan is activated, and pressure readings are taken between 25 Pa and 70 Pa in 5 Pa increments, measuring airflow through the building envelope.

Step 4: Final Calculations
Technicians calculate the air leakage rate at 50 Pascals (m³/h·m² @ 50Pa) based on airflow measurements.

Step 5: Smoke Testing (Leak Detection)
The building is pressurised to around 50 Pa, forcing air through leaks. Smoke testing highlights the exact locations, allowing contractors to seal problem areas efficiently.

Duration: A typical test and smoke investigation takes 2–3 hours, but we can stay on-site for a full day if remedial work is planned. Suggested materials for on-site fixes include mastic sealant, expanding foam, draught excluders, plasterboard, and grip fill adhesive.

Air Tightness Consultancy and Design Support

Achieving regulatory air tightness targets is increasingly challenging. Our consultancy services help at every stage of a project, including:

• Design reviews for air tightness

• Construction stage advice

• Pre-completion testing support

• Leakage investigation and reporting

By addressing air leakage early in the design and construction process, we reduce the risk of failing the final test.

Combined Air, Sound, and Ventilation Testing

Many clients now opt for our combined pre-completion testing packages, which include:

• Air Tightness Testing

• Sound Insulation Testing

• Ventilation Testing

Since our engineers are UKAS-accredited across multiple disciplines, all tests can be completed during the same visit, saving time and simplifying scheduling. Benefits include:

• Lower testing costs

• Faster project completion

• Better on-site coordination

We also offer out-of-hours testing, including weekends, to minimise disruption.

Nationwide Air Tightness Testing You Can Trust

With extensive experience conducting thousands of successful air tightness tests across London and the UK, APT Sound Testing provides practical advice and reliable testing services to help your project meet regulatory requirements efficiently.

We also offer a helpful air tightness checklist to ensure your building is fully prepared before testing.

✅ Need expert air tightness testing? Call us on 01525 303905 or email info@aptsoundtesting.co.uk to discuss your project and receive professional guidance from our experienced consultants.