Improve Building Performance with Professional Air Tightness Testing.
We specialise in identifying air leaks and assessing the overall airtightness of your property, helping you comply with building regulations, improve energy efficiency, and reduce heating costs. Serving London, Manchester, and nationwide.
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Air pressure testing, also known as air tightness testing or permeability testing, is a crucial diagnostic procedure used to quantify the rate of air leakage in a building. This process, often utilizing a blower door system, is essential for understanding a building’s true energy efficiency.
During the test, a large fan is installed in an external doorway. By depressurizing the building, outside air is drawn in through hidden gaps, cracks, or poorly sealed areas. By measuring the volume of air needed to maintain a specific pressure difference, our engineers calculate your exact air permeability rate.
Testing ensures your property is energy-efficient, fully compliant, and comfortable for occupants. Here is why it matters:
It’s a mandatory legal requirement under Part L in the UK to meet energy efficiency standards. Failing to comply results in certification delays and potential fines.
Uncontrolled air leaks lead to wasted energy and higher heating costs. Testing pinpoints weak spots so they can be sealed, drastically improving thermal efficiency.
A well-sealed building maintains consistent internal temperatures, eliminates cold drafts, and effectively blocks outdoor noise pollution.
Reducing air leakage significantly lowers carbon emissions and supports green building certifications like BREEAM, enhancing property marketability.
Sealing uncontrolled leaks prevents external moisture ingress, protecting the building from interstitial condensation, mold growth, and HVAC strain.
A comfortable, efficient, and draft-free property leads to happier tenants, far fewer maintenance complaints, and much better retention rates.
Testing is typically carried out when a building is structurally complete but before handover. Here are the key professionals who rely on our services:
Essential for new homes or commercial builds to meet energy efficiency rules, avoid fines, and secure Building Control sign-off for occupancy.
Used to verify that as-built details match the design intent, ensuring their buildings are functional, sustainable, and hit specific SAP targets.
Owners use testing to upgrade existing buildings, lowering utility overheads and making the space vastly more attractive to eco-conscious tenants.
Crucial when undertaking large extensions or renovations to ensure the updated building meets modern efficiency standards and reduces running costs.
Testing is performed when the envelope is sealed—windows and doors fitted—but ideally before cosmetic finishes are applied, allowing for easy remedial fixes.
Achieving a highly airtight building envelope is the cornerstone of modern sustainable construction. Under the strict requirements of Part L of the Building Regulations (2021 update), uncontrolled air leakage must be drastically minimized to curb carbon emissions and heat loss.
It is not uncommon for a building to fail its initial air tightness test due to unforeseen construction variables. This is why Diagnostic Air Leakage Testing is so valuable. When a building fails to hit its target design rate, our engineers don't just walk away. We keep the building depressurized and deploy diagnostic smoke tracing and thermal imaging to visualize exactly where the air is infiltrating.
Common failure points include poorly sealed skirting boards, unsealed pipe penetrations behind kitchen cabinets, gaps around window frames, and unsealed loft hatches. By identifying these issues while our fan is still running, your site team can apply targeted sealants and tapes immediately, allowing us to perform a re-test on the very same day.
We highly recommend conducting a diagnostic "Part-Built" test before plasterboard and final finishes are applied. Discovering a major leak in the primary air barrier after the building is decorated requires expensive, destructive remedial work. Finding it early costs almost nothing to fix.
The mechanics of the blower door test are straightforward but require precision calibration. The fan system is temporarily sealed into a primary external doorway. It pushes air in (pressurizing) or pulls it out (depressurizing), creating an artificial pressure difference—usually 50 Pascals—between the inside and outside.
Our advanced software then measures the exact volume of air passing through the fan required to maintain that 50 Pa pressure difference. This figure is calculated against the total internal surface area of the building envelope to generate the final air permeability metric (m³/h/m²@50Pa). The lower the number, the more airtight and efficient the building.
We understand construction delays cost money. Call us directly to find out our earliest availability for London, Manchester, and nationwide site visits.
We are a true one-stop-shop for building compliance. Click to learn more about our other testing and design calculation services.