Air Pressure Testing and Part L Compliance
Air Tightness Testing Liverpool
Professional air pressure testing for new-build homes, apartment schemes and commercial developments throughout Liverpool and the surrounding Merseyside area.
Air Tightness Testing and Part L Compliance in Liverpool
One Stop Consult provides professional air tightness testing for homeowners, builders, architects and developers throughout Liverpool and nearby Merseyside locations.
Air tightness testing, also known as air pressure testing, measures the amount of uncontrolled air leakage through the external envelope of a building.
Testing is commonly required for new-build residential and commercial developments before Building Control completion. The measured result is compared with the target used within the approved SAP or SBEM assessment.
Air Tightness Testing Across Liverpool and Merseyside
We support projects throughout Liverpool City Centre, Anfield, Aigburth, Allerton, Childwall, Wavertree, Woolton, Mossley Hill, Everton, Toxteth, Kensington and West Derby.
Nearby coverage also includes Bootle, Crosby, Formby, Kirkby, Prescot, Huyton, St Helens, Wirral and surrounding Merseyside areas.
Air Pressure Testing Services
Our Air Tightness Testing Services in Liverpool
Testing and certification support is available for residential and commercial buildings requiring Part L compliance.
01
Residential Air Tightness Testing
Testing for new-build houses, self-build homes, apartment blocks and housing developments.
02
Commercial Air Tightness Testing
Air permeability testing for offices, industrial units, warehouses, retail premises and mixed-use buildings.
03
Part L Compliance Testing
Final testing against the target used within the approved SAP or SBEM assessment.
04
Building Control Reports
Clear test reports prepared for submission to Building Control and the project energy assessor.
05
Air Leakage Investigations
Practical assistance identifying likely leakage paths where the building does not initially achieve its target.
06
Retesting
Follow-up testing can be arranged after suitable remedial sealing works have been completed.
What Does an Air Tightness Test Measure?
A calibrated fan is temporarily installed within an external doorway and used to create a pressure difference between the inside and outside of the building.
The airflow required to maintain this pressure difference is measured and used to calculate the building's air permeability.
The final result is compared with the design target stated within the relevant SAP or SBEM assessment.
External walls and construction joints
Window and external-door perimeters
Roof and ceiling junctions
Ground-floor perimeters
Service penetrations
Loft hatches and access panels
Dry-lining and skirting junctions
Mechanical and electrical openings
Your Required Air Test Target
There is not one universal pass figure for every building. The required result normally comes from the design-stage SAP or SBEM assessment.
The target forms part of the energy strategy used to demonstrate compliance with Part L of the Building Regulations.
The confirmed target should therefore be provided to the technician before the test takes place.
Preparing for the Test
When Is the Building Ready for Testing?
The external envelope and relevant internal finishes should be sufficiently complete to represent the finished building.
External Envelope Complete
Walls, roofs, windows and external doors should be installed and weather-tight.
Internal Finishes Advanced
Dry lining, skirtings, service boxes and airtightness details should be complete.
Services Permanently Sealed
Gaps around pipes, cables, ducts and other service penetrations should be sealed.
Ventilation Installed
Trickle vents, extract terminals and designed ventilation openings should be complete.
Temporary Openings Closed
Missing hatches, incomplete flues and unfinished service holes can prevent a valid test.
Power and Safe Access Available
The technician requires electrical power, safe access and a suitable external doorway.
Common Air Leakage Paths
Why Buildings Sometimes Fail the Air Test
Leakage is often concentrated around junctions, openings and penetrations rather than through the main areas of wall or roof.
Window and Door Perimeters
Incomplete sealing between frames, reveals and surrounding finishes can allow significant leakage.
Service Penetrations
Unsealed gaps around pipework, cables and ducts are common sources of uncontrolled airflow.
Loft Hatches
Poorly fitted or inadequately sealed loft hatches can affect the overall result.
Dry-Lining Voids
Air can move behind plasterboard where perimeter seals are incomplete.
Wall and Floor Junctions
Gaps around floor edges, skirtings and structural interfaces can form continuous leakage paths.
Electrical and Service Boxes
Consumer units, sockets and service cupboards may connect with hidden cavities.
Our Air Tightness Testing Process
We aim to make the testing and certification process clear from the initial booking through to issue of the report.
Provide the site address and project information.
Confirm the SAP or SBEM air permeability target.
Agree a suitable testing date.
Confirm the building is ready for attendance.
Complete the air pressure test.
Compare the result with the design target.
Issue the report or advise on remedial work.
1
Book the Test
Confirm the address, building type, target and preferred attendance date.
2
Site Readiness Review
Check that the building envelope and internal airtightness details are complete.
3
Air Pressure Test
Specialist equipment measures the building's air permeability.
4
Result Review
The result is compared with the approved SAP or SBEM design target.
5
Report and Certification
The completed report is issued for Building Control and the energy assessor.
Typical Liverpool Projects
Projects We Commonly Assist With
Why Choose One Stop Consult?
Accurate testing and proper site preparation can help prevent delays during the final Building Control stages.
We coordinate experienced technicians and provide clear guidance throughout the booking, testing and certification process.
Experienced air tightness technicians
Residential and commercial testing
Fast turnaround times
Competitive quotations
Part L compliant reporting
Building Control certification
Retesting support
Liverpool and Merseyside coverage
Information Required for a Quotation
Provide the full project address, building type, approximate floor area, number of dwellings or units and preferred testing date.
Please also provide the design-stage SAP or SBEM target, floor plans and contact details for the site representative.
Photographs showing the current stage of completion are useful where there is uncertainty about whether the building is ready.
Related Liverpool Services
Other Services Your Project May Require
Important Air Tightness Testing Information
The required air permeability target normally comes from the approved design-stage SAP or SBEM assessment and is not the same for every building. A successful result cannot be guaranteed before testing because performance depends on the quality and completeness of the building envelope.
The site must be sufficiently complete and safe for testing. Where the target is not achieved, remedial sealing and retesting may be required. One Stop Consult provides consultancy and coordination support through experienced air tightness testing specialists.
Frequently Asked Questions
Air Tightness Testing Liverpool FAQs
What is air tightness testing?
It measures uncontrolled air leakage through the external envelope and produces an air permeability result.
When is air pressure testing required?
Testing is commonly required for new-build residential and commercial developments before Building Control completion.
What result does my building need?
The required result normally comes from the approved design-stage SAP or SBEM assessment.
What happens if the building fails?
Likely leakage paths can be investigated, suitable remedial sealing completed and a retest arranged.
Do you test commercial buildings?
Yes. Testing is available for residential and commercial projects, including offices, warehouses and industrial units.
When is the building ready for testing?
The external envelope, windows, doors, finishes and service penetrations should be substantially complete.
How long does an air test take?
The time required depends on the building size, complexity and level of site readiness.
Do you cover all of Liverpool?
Yes. We provide air tightness testing throughout Liverpool and the surrounding Merseyside area.
What information is needed for a quotation?
Provide the address, building type, floor area, unit numbers, preferred date and SAP or SBEM target.
Request Your Free Air Tightness Testing Quote
Complete the form below with the Liverpool project address, building type, number of units and preferred testing date. Upload the relevant plans and SAP or SBEM target so our team can review the requirement and provide an appropriate quotation.