BUILDING REGULATIONS PART L

Air Tightness Testing

Accredited air pressure testing for new-build and converted homes and commercial properties across London, Essex and Kent, plus nationwide coverage.

At KM Sealants, air tightness testing is an essential part of delivering energy-efficient, Building Regulations compliant buildings. Whether you are working on a new build or a conversion, our fully qualified testers measure how much uncontrolled air escapes your property and provide the certified results you need to sign off the project.

With over 30 years in the sealing and construction trade, we deliver accurate, reliable testing and clear reporting, on time, every time.

Call us on 07388 200323 or 07799 450024, Monday to Friday, 9:00 to 17:00. We will book your test at a time that suits you and turn your report around quickly.

Fully qualified testers

Accredited, experienced engineers on every test.

Nationwide coverage

London, Essex, Kent and across the UK.

Accurate, compliant reporting

Certificates that satisfy Part L sign off.

Reliable and cost-effective

Dependable work at a fair, competitive price.

Free, no-obligation quotes

A fast, honest quote at no cost to you.

WHAT IS AIR PRESSURE TESTING?

Air pressure testing for residential and commercial buildings

Air tightness testing, also known as air pressure or air leakage testing, is a precise method of measuring the uncontrolled flow of air in and out of a building. Too much air leakage means avoidable heat loss, higher energy bills and a property that may fail to meet environmental standards.

Since April 2006, Part L of the Building Regulations has required air pressure testing on the majority of new builds and conversions, making sure properties meet minimum standards of energy efficiency and do not lose an excessive amount of air through the building envelope.

By pinpointing exactly where a building leaks, we help you reduce heat loss and cut CO₂ emissions. Depending on the type and number of properties in a development, testing can be carried out on a representative sample. If those units pass, no further testing is required.

HOW IT WORKS

Our air pressure testing process

01

Set up

We temporarily fit a calibrated blower door fan into an external doorway of the property.

02

Pressurise

The fan pressurises and depressurises the building so we can measure the pressure difference across the envelope, typically from 25 to 70 Pascals.

03

Measure

Using 50 Pa as the standard reference, we calculate the air leakage rate, expressed as m³/(h·m²) at 50 Pa.

04

Report

We leave the building exactly as we found it and send your certified report promptly, so your project can progress without delay.

THE KM SEALANTS DIFFERENCE

Why choose KM Sealants for air tightness testing?

Lower CO₂ emissions

Reduce your building’s carbon footprint and help meet modern environmental standards.

Lower energy bills

A well-sealed building loses less heat, cutting running costs for years to come.

Building Regs compliance

Certified results that satisfy Part L and keep your project firmly on track.

Our testers are fully qualified and experienced in carrying out rigorous, accurate air pressure testing. We work closely with builders, contractors and architects from the earliest stage of a project, because getting involved early gives you the best possible chance of passing first time. Reliable, cost-effective and available nationwide: that is air testing done properly.

Book your air tightness test today

For a free, no-obligation quote, or simply to discuss your project, call us on 07388 200323 or 07799 450024, or email info@kmsealants.co.uk. A member of the KM Sealants team will be happy to help.