Oliver Solcher
Bibliographic info:
10th International BUILDAIR Symposium, March 31/ April 1, 2017, Hannover, Germany

Purpose of the work

What is the status quo of airtight building in Germany? Are we well on our way or still far from the target? What about measuring practice in Germany? Should we concentrate on the documentation of measurement results or is it more important to exert a positive influence on the building process overall? Which requirements and targets are set by the legislators, which by the development banks?

Method of approach

Overview, compilation and review of publications.

Content of the contribution

In Germany, you are not required to collect data when you submit a test report as part of the certifications under public law. At the beginning, FLiB tried to provide support in this area, but the database is still very small, because there is neither an obligation to submit data nor is FLiB remunerated for its efforts. Therefore, we present the results from a qualitative survey. Legislators and development banks set requirements for the air permeability of the building envelope measured, when a reduced air change rate is to be applied to the calculation of the primary energy demand or certain funding programs are used. The presentation will give a short overview of this situation.

In 2014, FLiB together with the Aachener Institut für Bauschadensforschung und angewandte Bauphysik gGmbH (Aachen Institute for the Study of Construction Damage and Applied Building Physics) and the Fraunhofer-Institut für Bauphysik (Fraunhofer Institute for Building Physics) started a research project on the evaluation of air leakages sponsored by the research initiative “Building the future” (Forschungsinitiative Zukunft Bau) of the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR). This was finished at the end of 2016. The presentation will look back on the beginnings of the research project.

The principles of airtight building in Germany have long been ingrained in standards. However, there remains great potential when it comes to their implementation. Currently, airtight building is frequently not planned, but just happens. As a result, and in addition to the basic requirement in building law, the development banks now require an airtightness design for new buildings, rehabilitation projects, and the replacement of individual components.

Results and assessment of their significance

In Germany, the requirements for airtight building are well incorporated in regulations and legislation, as well as in the funding instruments. However, a lot remains to be done when it comes to the actual implementation. Airtight building cannot be realized by merely conducting an airtightness test. Airtight building includes planning, tendering, control, and coordination. Frequently, those in charge do not have a plan for airtightness, but assume, that their contractors will get it right. In these cases, the final measurement will only allow you to evaluate the leakage flow in sum. An evaluation of individual leakages is usually no longer possible without having to open the building parts.


The idea that airtight building must be planned throughout the entire process, still has to be better engrained in the minds of all parties involved in the building process.


For more information, please contact the reference author at: info@flib.de