Air Tightness Testing for Building Regulations — UK
Air Tightness Test Failing? We Fix It.
Don't let a failed test delay your completion certificate. Our ATTMA-certified engineers provide expert testing plus remedial advice to get you over the line.
💰 From £350 • ⏱️ 2-4 hours on site • 🔧 Remedial advice included
When Air Tightness Testing Is Required
Air tightness testing is mandatory for most new buildings and extensions under Approved Document Part L of the Building Regulations. The test measures how much uncontrolled air leakage occurs through the building fabric.
- New dwellings and residential buildings
- Non-domestic buildings over 500m²
- Extensions and conversions where SAP calculations are required
- Buildings following certain compliance routes under Part L
Standards & Methods — ATTMA & Part L Requirements
Testing follows ATTMA Technical Standards and Building Regulations requirements:
- ATTMA TSL1 for domestic buildings
- ATTMA TSL2 for non-domestic buildings
- BS EN ISO 9972 international standard
- Part L1A/L1B and L2A/L2B compliance paths
Test Process & Equipment
Pre-Test Preparation
- Building readiness inspection
- Sealing of intentional openings
- Photography of test setup
- Weather condition assessment
Testing Procedure
- Blower door fan installation
- Pressurisation and depressurisation tests
- Multiple pressure measurements
- Leakage rate calculations
Results & Certification
- Air permeability calculation
- Compliance assessment
- ATTMA certificate issued
- Remedial advice if required
Pass/Fail Criteria & Results
Target Performance Rates
Test Outcomes
Timeline & Coordination
Testing must be coordinated with construction programme and Building Control inspections:
- Book test 2-3 weeks in advance
- Building must be substantially complete
- Test typically takes 2-4 hours on site
- Certificate issued within 5 working days
- Coordinate with final Building Control inspection
Common Failure Points & Prevention
Typical Air Leakage Paths
- Service penetrations through walls/floors
- Window and door reveals
- Junction between different building elements
- Incomplete vapour barriers
Prevention Strategies
- Continuous air barrier design
- Proper sealing of penetrations
- Quality control during construction
- Pre-completion air tightness checks
Fees & Turnaround
Pricing depends on building size, location, and complexity:
- Single dwelling: £350-£600
- Multi-unit residential: £400-£800 per test
- Non-domestic: £500-£1,200+ depending on size
- Retest (if required): typically 50% discount
- Travel and accommodation may apply for distant locations
FAQs — Air Tightness Testing
When should I book the test?
Book 2-3 weeks in advance once the building is substantially complete but before final finishes.
What happens if my building fails?
We identify leakage areas, provide a remedial report, and offer discounted retesting once improvements are made.
Do I need design air permeability calculations?
Yes, these are typically required as part of SAP calculations and must be available before testing.
Can testing be done in winter?
Yes, but extreme weather conditions may affect scheduling. Indoor/outdoor temperature difference should be considered.
Need Air Tightness Testing That Passes?
Our ATTMA-certified team doesn't just test – we help you pass. With expert remedial advice and proven success rates, get your completion certificate without delays.
🌪️ ATTMA certified • 🔧 Remedial advice • ⚡ Nationwide coverage