Airtightness Testing

Blower door testing for Part L compliance in new builds, extensions, and conversions. On-site results with formal reports.

What is Airtightness Testing?

Airtightness testing, also known as blower door testing, measures how well a building is sealed to prevent unwanted air leakage. This measurement is critical for Part L compliance in domestic and commercial buildings.

The test involves pressurising the building using a powerful fan installed in an exterior door until the pressure reaches 50 Pascals (Pa). Air leakage is measured to determine if it meets regulatory requirements for energy efficiency.

Why It's Important

Energy Efficiency

Proper airtightness is essential to prevent unnecessary heat loss, resulting in lower energy costs and improved comfort.

Building Regulation Compliance

Part L of the Building Regulations requires buildings to meet specific airtightness targets for new construction and significant renovations.

In the 2021 revision of Part L, building owners must now achieve a specified maximum air permeability rate in m³/(h·m²) at 50 Pa pressure. For new dwellings, this is typically no more than 3 m³/(h·m²) at 50 Pa - a significant tightening from previous requirements of 7-8 m³/(h·m²).

The test helps identify gaps in sealing and can be crucial for achieving acceptable energy performance and passing Building Control inspection.

What's Included

  • Professional blower door testing with calibrated equipment
  • Accurate measurement of building airtightness at 50 Pa pressure
  • Detailed test report with results and interpretation
  • Support for Building Control officers with test data and documentation
  • Recommendations for improving airtightness if necessary

The Process

1

Get in Touch

Contact us with your project details - timing, property type, and location. We'll arrange a convenient time for testing, typically within 24-48 hours.

2

Site Preparation

We ensure all external doors and windows are properly closed and that the building has not been ventilated for at least 2 hours prior to testing.

3

Performance Testing

Blower door equipment is installed, and the test is completed in approximately 15-30 minutes.

4

Results & Report

We provide immediate results during the testing process, and a comprehensive report is delivered within 24 hours.

Part L Compliance

Airtightness testing is now a mandatory requirement for Part L compliance in:

  • New builds
  • Major extensions and conversions
  • Energy Retrofit Projects

We ensure that projects in our service area meet current Part L requirements while helping you navigate upcoming changes to these regulations, such as the proposed tightening to the 2030 MEES compliance timeframe.

Frequently Asked Questions

How long does the test take?

The actual airtightness test takes 15-30 minutes. The preparation and equipment setup typically takes around 30 minutes, making the total on-site time approximately one hour.

Do I have to be present during testing?

While not always necessary, it's recommended that someone is present to ensure access to all relevant areas and to confirm the conditions before and after the test. We can coordinate with your team at a time that suits you.

What happens if the building fails to meet requirements?

We can identify problem areas and recommend remedial actions. If the building does not meet Part L requirements, we work alongside your project team to find solutions that improve airtightness cost-effectively.

Need Airtightness Testing for your Project?

Get in touch with your project details. We typically respond within 24 hours and can arrange testing within a few days.

Get in Touch