BlowerDoor testing during refurbishment

When carrying out energy-efficiency improvements or alterations to an existing building, the airtightness of the envelope should be investigated at an early stage. A BlowerDoor test provides important information about its existing condition and helps plan an envelope that will remain airtight over the long term.

Airtightness testing does more than assess the existing building. It also provides a basis for planning, carrying out and subsequently checking the quality of refurbishment measures.

Assessing the existing building as a basis for refurbishment planning

Before a full or partial refurbishment begins, it is advisable to investigate the air permeability of the building envelope.

The test results provide planning-relevant information about existing leaks and help improve or redesign the airtight layer in a targeted way.

The measured leakage airflow can also serve as a baseline for setting target and limit values after refurbishment. A simplified single-point test may be sufficient for an initial assessment.

Identifying and assessing leaks

Assessing the existing building involves more than determining a numerical value. During a BlowerDoor test, existing leaks can be located and documented so that specific construction details can be developed to address them during refurbishment. Depending on the task, methods such as fog generators, anemometers or thermography are used. Typical weak points in the airtight layer result from missing or inadequate seals at penetrations and connections, including joints between building components, pipe and cable penetrations through the airtight layer, roof windows and dormers, roller shutter boxes, extensions and bay windows.

Quality assurance during refurbishment

Airtightness testing can accompany the entire refurbishment process.

It begins with an assessment before refurbishment and continues during construction while the airtight layer is still accessible. After the work is complete, a final test checks the airtightness achieved and allows the values before and after refurbishment to be compared.

Conclusion

A BlowerDoor test before refurbishment provides much more than a numerical value. It supports the assessment of the existing building, provides important information for planning the airtight layer and establishes a basis for effective quality assurance during and after refurbishment. This enables measures to be planned precisely, leaks to be detected early and the building's airtightness to be improved over the long term.

Frequently asked questions about BlowerDoor testing during refurbishment