Air Tightness Testing | EnviroSolution

Scope and evidence

Built around planning, development and compliance decisions.

Use this page to understand when the service is usually needed, what evidence is reviewed and what information helps us quote accurately.

Planning and regulator context
Clear deliverables and next steps
Linked services considered early

Air tightness testing measures uncontrolled leakage through the building envelope. The test result is important, but so is making sure the dwelling or building is at the correct completion stage and prepared consistently.

When this service is used

Used for Building Regulations, Part L compliance, completion evidence and projects where building-envelope performance must be verified.

Planning and project supportUsed as Building Regulations completion evidence and to verify the as-built envelope performance assumed in energy calculations.

Risk and programme controlTesting before the final handover deadline leaves time to diagnose and seal leakage if the first result does not meet the design target.

What the report normally includes

Air tightness test scope confirmation
On-site test and result evidence
Diagnostic advice where a test fails
Completion-ready reporting
Recommendations for remedial sealing if required

What we need from you

Providing the right information at the start helps us confirm the scope, quote accurately and avoid back-and-forth once the work is underway.

Site address and access details
Dwelling or building type
Target air permeability if known
Build stage and readiness
Required completion date

A successful air test starts with building readiness

Air tightness testing using a blower door system at a UK home. — Building performance testing supporting compliance and improved energy efficiency.

What a robust scope should cover

Confirmation of building type, target and test readiness
Preparation of intentional openings in accordance with the test method
Fan pressurisation or depressurisation and measurement of airflow
Calculation of the air-permeability result
Diagnostic leakage advice where a result is above target
Test evidence for the compliance and energy-assessment workflow

What the work should leave you with

A measured as-built air-permeability result
Clear pass/fail comparison against the project target
Practical feedback on leakage paths where further sealing is needed
Evidence that can be coordinated with final energy-compliance calculations

Why the detail mattersThe test should be planned as part of completion, not treated as a last-minute certificate. That preserves time for remedial sealing and retesting if needed.

Useful to know before you enquire

The building must be test-readyIncomplete seals, missing traps, unfinished service penetrations or temporary openings can distort the result or cause an avoidable failure.

Know the design targetThe target air permeability should come from the project energy and Building Regulations strategy so the result can be assessed correctly.

Early diagnostic testing can helpOn high-performance buildings, an earlier test may identify envelope issues before finishes conceal leakage paths.

A failed test can often be improvedTargeted sealing of identified leakage paths can improve performance before a retest.

FAQ

Common questions

When should an air tightness test be booked?

Book early enough to secure the required completion date, but the building must be at the appropriate test-ready stage when the engineer attends.

What happens if the building fails?

We can discuss likely leakage paths and the practical remedial steps needed before a retest.

Does the air test affect SAP?

For new dwellings, the as-built air-permeability result can feed into the final energy-compliance calculation, so the two services should be coordinated.

Related services

These services are often reviewed alongside Air Tightness Testing depending on the site, planning context and proposed development.

Structured enquiry

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Our custom enquiry builder asks service-specific questions so we can confirm the correct scope, identify linked services and avoid unnecessary delays.

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