Build Comply

Air Tightness Testing

Retrofit, Domestic, Residential, Commercial, Plenums, Smoke Shafts.

Are you looking for Air Tightness Testing?

To comply with Approved Document Part L1 and L2 of the Building Regulations, ensuring your building is air tight is essential.

Likewise, this too is paramount in a retrofit project.

Air Tightness Testing, also known as air infiltration, air permeability, air pressure or air leakage testing is required.

Air Testing assesses the level of conditioned (heated or cooled) air leakage. Basically this is known as infiltration, evidently felt as uncontrolled ventilation. By ensuring that the building meets or exceeds the air permeability rating specified in a design stage SAP or SBEM Calculation, Air Testing guarantees energy efficiency and performance.

Our testing is routinely carried out using a blower door. Following the methodology to ATTMA standards in line with CIBSE TM23 or ISO 9972:2015.

Are you ready for your Air Tightness Test?

Click here to find our Air Permeability Site Status Checklist covering common leakage area preparation and recommended sealing

Along with your Air Testing we can provide a full suite of diagnostics. Thermal imagery and smoke testing coupled with a depressurisation test can help massively identify problem areas.

Learn more about Air Tightness in the below sections, where we answer to most frequently asked questions.

If your project requires Air Testing to meet a design air permeability for SAP Compliance, Building Control request, New-Build or Retrofit, feel free to reach out to us at 01621 493594 or visiting our contact page. Building Compliance Testing commits to providing a quote within 24 hours. Upon acceptance we can dispatch a tester to your site within 48 hours for Air Testing in London and Home Counties. Secure Expert Professional Air Testing services today by booking with us.

Testing and ATTMA Certificate for as little as £145+VAT

Have a project in mind? Let’s get to work.

What is Air Tightness

Air tightness tests have a variety of names. Air permeability, air infiltration and air leakage tests are all exactly the same as an air tightness test.

Air tightness is a measure of how much air leaks out of a dwelling per hour, per metre cubed of building envelope – m³.hr/m²

What is a Building Envelope?

A ‘building envelope’ is the floor area, walls area and roof area all added together – as if the building were wrapped in an envelope.

These are all the areas where air could potentially leak out of a building.

Why do I need an Air Tightness Test?

To check for air leakage out of the building
To make sure you’re not too air tight
To comply with building regulations

How is a Air Test Conducted?

We put a large fan in an expandable door frame, which goes into an external door in the house, normally the front door. All other external doors and windows will be closed and all internal doors kept open.

The fan will then typically depressurise the house to a pressure of at least -50Pa. An anemometer reads the internal pressure, external pressure, and the strength that the fan is having to work at to create that pressure difference.

10 readings are taken at different pressures, and along with other factors such as barometric pressure and temperature, fed into a software which calculates the air leakage.

More recently there is another method called Pulse Testing.

What is a Design Air Permeability (DAP)?

DAP stands for Design Air Permeability. It is the target score for the air test, determined in the SAP Calculations

It is the amount of air leakage allowed for a particular property in order to gain building control sign-off. The building regulations state that a score of 10m³.hr/m²is sufficient for a pass, but increasingly target scores determined in SAPs are far lower than that, around 5m³.hr/m²

At what stage do I need an Air Tightness Test?

Testing is typically performed post second fix. All major penetration to walls and floors must have already been made. On top of this, you’ll need:

All service penetrations sealed
Trickle vents installed
Loft access hatch in place
Plumbing complete with water in the traps
Seals fitted on external doors
Electrical outlets fitted

Are you ready for your Air Tightness Test?

Click here to find our Air Permeability Site Status Checklist covering common leakage area preparation and recommended sealing

Does every plot need an Air Test?

Under Part L Building Regulations 2021 all new-build dwellings must have an air leakage test carried out.

Under old regulations not always. Sample testing is only allowed if the plots you do test beat their target score by 2m³.hr/m². This means, if your DAP is 10, but you can score 8 on the plots you do test, you may not need to test every plot – however this is still at the discretion of building control.

With more and more low target scores, the likelihood of beating it by 2 is less and less likely.

How do I make sure I Pass?

While we will never guarantee a pass, we will do as much as we can to help you.

Before we come, take a look at our site status checklist. It highlights common air leakage areas in a property. If you address all of these, you give yourself a good chance.

If a test is not passing first time, we will help you out as much as we can within a fair time frame. If you ensure you have tubes of mastic and expanding foam with you on the day, our engineers can point out air leakage areas during the testing. If they are small enough to fix at the time, we’ll wait and re-test the property, doing our best to get you a pass first time.

Is it only New Builds that need an Air Test?

Short answer… yes.

However, we would argue that it is a good idea to get any house that has not already got an air test certificate tested for air tightness. It’s a great way to locate air leakage areas, plug them up and save yourself money on heating. It’s also far more cost effective than other methods, such as thermographic surveys.

Learn more about retrofit services over at our sister company’s website – BEE Homes, Building Energy Efficient Homes.