Air Tightness Testing — Domestic & Commercial

Air Tightness Testing, also known as Pressure Testing, is a legal requirement for all newly constructed residential and commercial buildings under Part L of the Building Regulations. The test precisely measures air leakage — the uncontrolled movement of air through gaps and imperfections in the building fabric. This is distinct from ventilation, which is the deliberate, controlled flow of air through purpose-designed ventilators.

Every new development must demonstrate compliance with Part L energy performance standards. We carry out certified air testing across the full UK, with particular coverage in London, Sussex, Hampshire, Dorset and throughout the South of England.

Why Choose Us?

• UKAS-accredited engineers on every project — fully qualified and experienced
• A pre-test preparation checklist is issued on booking, covering common leakage areas
• On failure: engineer locates leakage at no charge — and if remediated on-site, a FREE re-test is conducted
• Test results delivered on-site immediately upon completion
• Professional, reliable service aligned to your project schedule
• Price match guarantee — we will match any like-for-like quotation

How Our Testing Process Works

Our engineers deploy a calibrated door blower fan at the main entrance. All deliberate ventilation openings are sealed per the pre-test checklist. The fan de-pressurises the building to determine its air permeability — expressed as m³/hour per m² of internal envelope area at 50 Pascals. A successful result must meet or be below the Design Air Permeability stated in the SAP Calculations.