Airtightness Testing
Air pressure testing for self-build homes, residential developments, commercial buildings and retrofit projects across East Anglia, with UK-wide project capability.
Been asked for an air test or airtightness certificate? We measure air leakage, explain your result and provide clear reporting for your project. Our practical housebuilding experience helps us investigate problems and guide your next steps.
What is an airtightness test?
An airtightness test measures how much air leaks through gaps in the outside walls, roof, floors and their junctions. It is also called an air pressure, air permeability or blower-door test. A calibrated fan temporarily fitted in a doorway creates a controlled pressure difference so we can measure leakage.
Your air permeability result is usually expressed as m³/(h·m²) at 50 pascals. We explain what it means against the target for your project. Airtightness controls unwanted leakage; a building still needs its designed ventilation.
Who needs testing, and when?
We test individual homes, residential developments, commercial buildings and existing properties undergoing retrofit or investigation. For new-build compliance, the requirement and target depend on the building, applicable regulations and project specification. In England, air pressure testing forms part of Part L energy-performance compliance.
Contact us early with your drawings and target from your energy assessor or project team. Final testing needs the building ready in the correct test condition. An earlier diagnostic visit can help find leakage while construction details are still accessible.
How to prepare for your test
Before the visit, agree the test boundary, required result, access and site-readiness requirements with us. As a starting point:
Complete the relevant external doors, windows, hatches and building fabric. Finish and seal construction joints and service penetrations as required. Provide safe access, agreed power, parking and any site induction. Make sure drainage traps contain water where applicable, and coordinate other trades so work does not disrupt the test.
Ventilation openings and building systems must be prepared to suit the test method. Follow our project-specific instructions rather than sealing openings indiscriminately. Tell us about incomplete work, access restrictions or occupied areas before we arrive.
What happens on the day?
We review the property and agreed test conditions, set up the fan and pressure-measurement equipment, and record the readings. We explain the result and discuss any issues identified. The time required depends on the size and complexity of the building, access, preparation and any investigation needed.
You receive the relevant test report or certificate for the agreed service. It records the measured result; it is not a guarantee of a pass or overall Building Control approval. Confirm your reporting requirements and deadlines when booking.
If the result falls short
Our team worked as carpenters, bricklayers, site managers and general builders before specialising in testing. That experience helps us relate leakage to construction details and explain practical next steps.
Depending on the agreed scope, we can investigate likely leakage paths through inspection, smoke testing and thermal imaging where conditions are suitable. We explain where remedial work or further investigation should be focused and discuss retesting after corrections. Additional diagnostic work and return visits are agreed as part of the scope.
One home or a phased development
Self-builders receive clear guidance on preparation and the meaning of the result. For developers and Tier 1 contractors, we discuss plots, phases, site readiness, access and reporting so testing can be coordinated with your programme.
Send your anticipated plot handovers and any project-specific requirements early. If you also need ventilation or sound testing, tell us at quotation stage so we can discuss suitable coordination and visit arrangements.
Common questions
How much does an airtightness test cost? The quotation depends on the building size and type, location, number of properties, access and scope. Send drawings, your site postcode and preferred dates for a project-specific quote.
What result do I need? Use the target agreed for your building and energy assessment. There is no single target suitable for every project; send us your specification or assessor’s details if you are unsure.
Is this the same as an extractor fan test? No. Airtightness testing measures leakage through the building fabric. Ventilation testing measures airflow through fans and ventilation systems. Your project may need both.
Arrange airtightness testing
We support projects across Suffolk, Essex, Norfolk and the wider East Anglia region, with UK-wide project capability. To request a quote, send your postcode, building type, drawings if available, number of properties, project stage, target result and preferred dates.
Request an airtightness testing quote →
Related services: ventilation & extractor fan testing · specialist fault finding · sound insulation testing
Regulatory guidance: Approved Document L for England. The applicable edition and transition arrangements depend on your project.