Air Tightness Testing
Residential | Commercial | Passiv Haus | Room Integrity
  • On site ATTMA certificates
  • Immediate on-site diagnostics & re-testing
  • Flexible appointments to suit you
  • Pre-test site assessments available
  • Low cost for multiple plots

We deliver efficient ATTMA Certified, price match guaranteed Residential Air Tightness Testing services to meet all Part L1A & L2A Building Regulations compliance requirements.


Whether it be a single self-build, small projects or large scale development sites with national construction companies we offer the same comprehensive service including full diagnostic reports and remedial advice from our team of skilled & fully ATTMA accredited engineers where necessary to ensure success is achieved. 

BREW Compliance - Air tightness testing, air pressure testing, air permeability testing, air tightness, air permeability, blower door testing, Air Test, L1A Air Test, m3/h/m2@50Pa

Single Test

Available From

Nationwide Air Tightness / Pressure Testing to a single plot including full remedial advice and diagnostics. We will even carry out same day re-testing if the remedial works can be completed within a time limit. This is above and beyond our competitors. Giving you some peace of mind and confidence in BREW Compliance Ltd.

BREW Compliance - Air tightness testing, air pressure testing, air permeability testing, air tightness, air permeability, blower door testing, Air Test, L1A Air Test, m3/h/m2@50Pa

Multiple Plot

Available From

Air Tightness Tests carried out to additional plots within the same site visit. This can help you achieve those last final CLM sign offs for the end of the month. As always, our knowledgeable technicians are here to help & work with you to achieve the required outcome.

BREW Compliance - Commercial Air tightness testing, commercial air pressure testing, commercial air permeability testing, commercial air tightness, commercial air permeability, commercial blower door testing, Air Test, L1A Air Test, m3/h/m2@50Pa



Commercial buildings are just as important to achieve the design air permeability stated on the design SBEM/BRUKL report. Warehouses, offices, Centers and other industrial related properties all must able to withstand air pressure/permeability testing.

Air Tightness Testing Explained

An air tightness test pretty much does what it says on the tin, and is a test of a buildings air seal to ensure no heat is instantly lost or draughts and cold spots affecting the occupants, and that ventilation is only occurring via the designed routes not poor building fabric in a bid contributing the reduction of Co2 emissions as part of government plans. 

Part L Building regulations outline that the minimum air tightness of a new building must achieve no worse than 10 m3/(h.m2) at 50 Pa. However it has become common practice to see a target of 5 m3/(h.m2) at 50 Pa as an easy and cost effective way to help improve the DFEE (Dwelling Fabric Energy Efficiency) over the target generated in SAP as explained in more detail here

The test must be conducted by an accredited engineer operating under a body such as ATTMA (Air Tightness Testing Members Association) which is what we offer here at BREW Compliance. 

Passiv Haus Testing Explained

BREW Compliance are also fully qualified to carry out Air Tightness Testing for Passives Haus requirements (n50). Conducted using calibrated equipment and testing in accordance with

BS EN 13829.

The concept of Passiv Haus (translating to passive house) buildings was founded by a German physicist by the name of Wolfgang Feist. He started the revolution of more efficient and environmentally friendly buildings. The standard of passiv haus testing (n50) is more strict that than a usual air tightness test (q50). Strict measures are put in place in order to ensure a near completely air tight building. Saving fuel and money on heating and cooling passiv haus builds. 

Areas & volumes are calculated differently when our technicians carry out the size calculations. 

q50- Using Envelope Area m2

n50 - Using Volume m3

Passiv Haus has a set minimum target of 0.61. Written n50 ≤ 0.6 h-1 @ 50Pa. The result of any air test must be less than the set target to comply. Air tightness targets for traditional builds will be determined by the design stage SAP report.

As passiv requires the air leakage to be minimal it is recommended for an air permeability test to take place at several stages of the development.

Initial Test 

The initial test of the passiv haus regime is required to be carried out once the initial air barrier has been completed and before services are installed, a test is conducted to underline any leakage areas early on in the project. This makes it easier and more effiecnt to stamp out any leakage points at this stage.

Once the building services have been installed. The next step of testing can take place. At this stage it is important to test for any new leakage areas that may formed as the services were installed. If any are found these can now be fixed before the final finishes are installed on the property.


Once the building has been completed the final stage test can be performed. This is now in use for the building control sign off. While the initial testing is to outline and detect any underlying problems, the final completion 

test is to confirm the result is in compliance with the Passiv Haus standard.


Pre - Completion Test

Completion Test

How is a Passiv Haus Test Carried Out?


How its done - Our technicians will visually inspect the property before the equipment is set up. They will then tape and seal any necessary service pipes that may penetrate the air tight barrier. Air tight membrane is used in the fabric make-up of a passiv haus so in order to stress the membrane, the test is performed in two ways. First, the building is tested under positive pressure, pulling air into the building. Then the test is repeated under negative pressure, drawing the air out of the building. The final result of the passiv haus test is then an average score of both of the tests conducted.

ATTMA Air Tightness Testing, Residential
ATTMA Air Tightness Testing, Residential