Airtightness in a timber house: design and blower door testing
Airtightness limits uncontrolled flow through the envelope. It is designed as one continuous layer and verified through inspection and pressurisation testing.
This guide sets out checks and decisions. It does not replace design by qualified professionals or requirements imposed by the competent authority. Solutions depend on the site, structural system and required performance.
The decision to make
Draw one continuous line
Walls, roof, floor, windows and services must connect without gaps in the airtight layer.
Reduce penetrations
Every cable, pipe and fixing needs a planned location and a seal compatible with maintenance and durability.
Test before finishes
An intermediate test finds leaks while accessible; the final test records performance of the completed building.
Interpret the figure
The result must be compared with target, volume and protocol and does not alone locate defects.
Documents and evidence to request
- airtight-layer drawings
- penetration register
- tape and interface specifications
- intermediate test report
- final report with conditions and instruments
Every document should refer to the same design revision. A sound report based on obsolete geometry does not close the risk; it must be coordinated with drawings, details, specifications and site inspections.
The mistake to avoid
Running only a final test can document failure after economical access for repair has disappeared.
A practical sequence
- Define the required performance and site conditions.
- Collect surveys, reports and applicable requirements.
- Compare alternatives against explicit criteria, not a standard detail.
- Coordinate structure, envelope, services and installation sequence.
- Record inspections, results and responsibilities before work is concealed.
Frequently asked questions
Does the test measure insulation?
No. It measures induced air change; insulation and airtightness are different properties.
Can every leak be found?
Testing supports location with instruments and inspection, but the overall number does not identify each point.
Does airtightness matter in summer?
Yes. Uncontrolled air paths affect comfort and system operation across seasons.
Conclusion
A blower door test adds value when it completes a process of detailing, installation responsibility and checks at the right stages.
The existing call to action on this page can be used to submit the project to MANINI Villae. A reliable assessment requires site data, design information and checks by the appointed professionals.
Primary sources consulted
- Agenzia CasaClima — Blower Door Test, accessed 4 September 2026.
Want to build your timber villa with MANINI?
Verify your project →
