Extension Calculations (Airtightness Pulse Testing)

What Are Extension Calculations?

Extension calculations in airtightness pulse testing are used to estimate and verify the air leakage rate of home extensions or modified sections of a building. They ensure that any new or extended part of a property maintains airtightness standards consistent with the rest of the structure and complies with Building Regulations (Approved Document Part L).

These calculations are particularly valuable when a full air test is not required or feasible, allowing a compliant and cost-effective assessment of the extension’s airtightness performance.

Why Extension Calculations Matter:

Building Regulation compliance – Essential for demonstrating that new extensions meet airtightness and energy efficiency standards under Part L.

Accurate performance prediction – Understand how extensions impact overall building airtightness and energy performance.

Cost-effective and non-intrusive – Avoid unnecessary full-building tests while ensuring your project remains compliant and efficient.

What We Provide:

• A detailed airtightness extension calculation tailored to your specific project.

• Integration with existing test data or design specifications.

• A comprehensive report suitable for submission to Building Control.

• Practical recommendations to help you achieve compliance and optimise energy performance.

Why Work with AirMetric?

• Specialists in Airtightness & Building Performance Testing – extensive experience across all project types.

• Reliable and compliant results – all calculations and tests meet current UK standards and regulations.

• End-to-end support – from initial design advice to final sign-off, ensuring your extension meets airtightness and energy performance goals first time.