At Stroma Built Environment, we provide comprehensive air permeability testing services for domestic and commercial projects of all sizes. Whether you're building a single home or managing a significant commercial development, our experienced team ensures your project achieves Building Regulations Part L compliance and meets all performance targets.
Our Air Tightness Test Services
Using calibrated blower-door equipment, Stroma engineers conduct thorough air permeability tests in accordance with the ATTMA methodology. We explain the process as we go, provide immediate feedback on results, and deliver comprehensive reports within 48 hours.
If a test fails, we use advanced smoke diagnostics to quickly and effectively identify air leakage paths. Our engineers provide clear, actionable feedback, and our specialist remedial sealing team can coordinate repairs to get your project back on track.
Our 20+ years of expertise and comprehensive diagnostic capabilities can help you navigate this more demanding regulatory environment successfully. We support projects across residential (new build and retrofit), commercial, healthcare, education, industrial, and mixed-use developments.
Domestic Air Tightness Testing
Air permeability testing is mandatory under Building Regulations Part L for all new homes and large extensions. We provide comprehensive testing in compliance with ATTMA TSL1 and CIBSE TM23 standards, making the process straightforward and stress-free for homebuilders and developers.
Our domestic service includes:
- Pre-test guidance on temporary and permanent sealing strategies
- Rapid on-site testing (typically 1-2 hours per dwelling)
- Smoke diagnostics to identify air leakage paths if tests fail
- Detailed reports suitable for SAP calculations and Building Control
Commercial Air Tightness Test Services
For commercial projects, we deliver professional air permeability testing services for buildings of all scales and complexities. Testing to ATTMA TSL2 and CIBSE TM23 standards, we support projects from design through to completion and handover.
Design stage support:
- Air tightness strategy development and review
- Specification guidance for contractors and subcontractors
- Target setting for Part L and BREEAM compliance
Testing services:
- Multi-zone testing for large, complex buildings
- Phased testing programs aligned with construction schedules
- Calibrated blower door systems and trailer fans for buildings of all sizes
- Advanced smoke diagnostics to pinpoint air leakage paths
Post-test support:
- Detailed reporting within 48 hours, suitable for SBEM calculations and Building Control
- Comprehensive feedback identifying specific problem areas
- Remedial sealing coordination if required
Not sure if you need an air tightness test? Our experienced team can help you understand your responsibilities throughout the whole development process.
Contact us today to request a quote and discuss your requirements. Our team is ready to help!
Comprehensive Testing Capabilities
Expert Testing and Consultancy with Stroma
Alongside accredited testing, our experienced consultants provide practical guidance to support regulatory compliance, certification, and better-performing buildings from design through to completion.
Building Regulations Part L Compliance
Our accredited air tightness testing provides the evidence required to demonstrate compliance with Building Regulations Part L: (8 m³/(h·m²) at 50Pa for both domestic and commercial buildings. We also offer practical guidance on air tightness strategies, helping identify potential issues early and reduce the risk of delays or remedial works.
BREEAM Compliance
For BREEAM credits, buildings must achieve an air permeability of 10/8m³/(h·m²) or better at 50Pa. Better air tightness directly improves your ENE 01 (energy) credit rating. Our testing contributes to the overall building performance assessment and can be combined with thermographic surveys to earn MAN 04 (fabric performance) credits.
Passivhaus Certification
For projects targeting Passivhaus certification, we provide specialist air tightness testing alongside expert consultancy to help you achieve strict air permeability and energy performance requirements with confidence. Our certified consultants will deliver specialist guidance and assurance from end to end.
Why Partner with Stroma for Air Leakage Testing?
With over 20 years' experience and a nationwide team of ATTMA-certified engineers, we're one of the UK's largest and most trusted air tightness testing providers. We've tested thousands of buildings across all sectors, bringing unparalleled expertise to every project.
What sets us apart:
- 20+ Years' Experience: Engineers with extensive field expertise who can solve problems on site.
- Expert Diagnostics: Efficient identification and resolution of air leakage issues without unnecessary remediation.
- Full Smoke Diagnostics Included: Comprehensive leakage identification included in test fee.
- Complete, Detailed Reporting: Thorough documentation with actionable feedback delivered within 48 hours.
- Design Stage Consultancy: Early engagement to develop effective air-tightness strategies.
- UKAS Accredited Testing (Laboratory No. 2731): Meeting all regulatory and BREEAM requirements.
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Frequently Asked Questions
Can Stroma provide air permeability test services for commercial premises?
Yes. Our highly skilled and certified consultants provide air leakage testing for a wide range of commercial premises, from retail units and offices to schools, hospitals, and large-scale industrial warehouses. We also specialise in climate-sensitive environments such as museums, galleries, and data centres.
Beyond the test itself, we can identify:
- Gaps between walls, ceilings, or floors
- Inadequate sealing around doors, windows, or architraves
- Hidden leakage paths via advanced smoke testing methods
We also offer remedial sealing and fire stopping services. These are essential for reducing air leakage risks in the event of a fire or ensuring a building passes after an initial air permeability failure.
Can Stroma help with complex commercial sites?
Yes, our engineers have extensive experience testing:
- High-rise office and residential towers
- Retail and leisure developments
- Healthcare facilities (hospitals, care homes)
- Educational buildings (schools, universities)
- Industrial and warehouse facilities
- Mixed-use developments
What are the current air tightness requirements under Part L Building Regs?
In June 2022, the maximum permitted air permeability was reduced from 10 m³/(h·m²) to 8 m³/(h·m²) at 50Pa for both domestic and commercial buildings – a 20% improvement requirement that demands higher construction standards and more careful attention to air tightness.
- Absolute maximum: 8 m³/(h·m²) at 50Pa (for both domestic and commercial)
- Notional building baseline: 5 m³/(h·m²) at 50Pa (SAP/SBEM calculations use this as the comparison)
- BREEAM target: 10 m³/(h·m²) at 50Pa for credits (though better performance improves energy ratings)
This means achieving closer to 5 m³/(h·m²) will make it significantly easier to meet overall energy performance and carbon-emission requirements, particularly with the new Primary Energy Rate (TPER) metric introduced in 2022.
What is a good air tightness test result?
A "good" result is relative to your project’s specific design target. Under Building Regulations Part L, the maximum acceptable air permeability score is 8 m³/(h·m²) at 50Pa for both domestic and commercial buildings. A high-performance building may score 1-3.
How long does an air leakage test take?
In most cases, our assessors can complete a standard air permeability test in 1 to 2 hours. For larger, more complex commercial projects or multi-zone buildings, the process – including setup and preparation – typically takes between 2 and 4 hours. We can usually provide immediate feedback on-site as soon as the test is concluded.
What standards and accreditations does Stroma work to?
Stroma Built Environment is a UKAS-accredited laboratory (No. 2731), and our engineers are certified to the highest industry standards. We work in strict accordance with:
- ATTMA TSL1 (Domestic) & TSL2 (Commercial)
- CIBSE TM23 (Chartered Institution of Building Services Engineers)
- Building Regulations Part L 2021
- BREEAM (approved testing provider for ENE 01 credits)
What is your test calculation methodology?
For full details on our air tightness test methodology, please view our testing methodology document.
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