Air Tightness Testing Services

Who Is Air Tightness Testing For?

Air tightness testing may be required or useful for new-build projects, major refurbishments, retrofit projects, landlords, homeowners, developers, architects, contractors, property managers and commercial building owners. It helps identify uncontrolled air leakage and can provide evidence for compliance, design review, remedial planning or retrofit decision-making where applicable.

For existing properties, the test can help identify draughts and leakage paths that may affect comfort and energy performance. For new-build or major works, testing may be needed to support Building Regulations Part L requirements, depending on the project type and applicable route. Outcomes depend on the building condition, test conditions, remedial work and final design requirements.

What's Included in Our Service?

The service scope depends on the property, project stage, testing requirement and agreed instruction. Air tightness testing normally involves preparing the building, setting up testing equipment, measuring air leakage and providing results or a report for the agreed purpose.

Depending on the agreed service, this may include:

Common Issues and Failures in Air Tightness Testing

Common leakage areas can include gaps around windows and doors, service penetrations, loft hatches, pipework, ductwork, electrical penetrations, floor junctions, wall junctions, skirting lines, ceiling voids and poorly sealed construction joints.

Test failures or poor results may be caused by incomplete sealing, unsealed penetrations, unsuitable preparation, construction defects, poor workmanship, weather conditions or unrealistic design targets. Findings should be reviewed before remedial work is agreed.

Air leakage should be considered alongside ventilation. Over-sealing a building without adequate ventilation can create indoor air quality, condensation or moisture risks.

How Air Tightness Testing Can Support Landlords and Homeowners

For landlords and homeowners, air tightness testing can help identify uncontrolled air leakage that may affect heating demand, draughts, comfort or retrofit planning. The test can provide useful evidence before remedial work, insulation improvements, ventilation review or wider energy performance upgrades.

Testing may support discussions around EPC improvement or property performance, but it does not guarantee lower bills, legal compliance, reduced vacancies, property value increases or tenant demand. Outcomes depend on the property, test result, remedial work, energy tariffs, occupancy and usage.

Air tightness testing frequency depends on the project type and purpose. New-build projects may require testing at completion or at key stages depending on the Building Regulations route. Existing buildings may be tested before retrofit, after remedial sealing, or when building performance issues need investigation.

Air tightness testing may require access to rooms, external doors, ventilation openings and building services. Disruption depends on building size, occupancy, preparation requirements and test method. For commercial premises, testing can often be planned around operational needs, but this should be confirmed before booking.

The required air tightness score depends on the building type, design target, Building Regulations route, energy model and project specification. Lower air permeability generally indicates a more airtight building, but airtightness must be balanced with suitable ventilation. GOV.UK publishes Approved Document L guidance for the conservation of fuel and power in buildings.

Weather conditions can affect air tightness testing. High winds, extreme temperatures or unsuitable site conditions may affect test accuracy or whether testing can proceed. The testing provider should confirm preparation requirements and any weather limitations before the visit.

Result timescales depend on building size, test complexity, reporting requirements and assessor availability. Basic results may be available sooner, while a full report or remedial recommendations may take longer. The expected reporting timeframe should be confirmed when booking.

No. Air tightness testing measures air leakage and may help identify leakage paths. Draught reduction depends on suitable remedial work being completed after the test.

No. Air tightness testing measures uncontrolled air leakage through the building fabric. Ventilation testing or ventilation commissioning checks whether intended ventilation systems are working correctly. Both may need to be considered together.

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