Rechtsanwalt Ulf Köpcke
Bibliographic info:
11th International BUILDAIR Symposium, 24- 25 May 2019, Hannover, Germany

Purpose of the work

It is now internationally accepted by the disciplines of structural engineering and building physics that in the interests of energy efficiency heated buildings should be equipped with airtight building envelopes. The airtightness of the building envelope as a fundamental construction objective is therefore no longer in question. But it is increasingly the case that, on the one hand, the level of technical requirements and the technical avoidability of air leaks and, on the other, the deficiencies which in the opinion of the building contractors are supposedly acceptable are now becoming a focus of legal dispute. This paper aims to illustrate the legal perception of the technical controllability of air leaks in the building envelope that should apply in Germany but also generally in the legal arena throughout Europe.

Method of approach

This paper is a direct continuation of Klaus Vogel's preceding paper on "Technical requirements for the avoidability of leakages" and supplements this with a consideration of civil law aspects.

Content of the contribution

In this paper, taking as a starting point the legal situation in Germany, albeit comparable to that in Europe, the relevant issues in everyday legal practice regarding the airtightness of building envelopes are presented and commented on. In particular, generalizable argumentation strategies for out-of-court settlement of legal disputes about the airtightness of the building envelope are outlined. Generally, this paper is to be understood as an essential complement to the previous paper by Klaus Vogel on "Technical requirements for the avoidability of leakages".

Results and Assessment of their significance

Overall, there are three aspects (as a minimum) to be considered:

  1. The need for the execution of airtight building envelopes is now well established in construction planning and construction practice and this has now become the aim throughout Europe.
  2. Leaks through the building envelope that, although perhaps minor and only commencing after a lengthy period, entail a high risk, and have now become a major problem confronting structural engineering and building law in the context of the planning and execution of airtight building envelopes.
  3. From the aspect of both construction practice and building law, there results the logical consequence: Under building contract law, avoidable poor performance by construction workers should under no circumstances be deemed to be "acceptable". The current status (spring 2019) of construction planning, construction management and construction technology unequivocally verifies that there is not only no reason but also no justification to tolerate such deficiencies with regard to the airtightness of building envelopes.


This paper aims to present approaches to show how, in all European legal systems, the latest scientific findings on the cause, avoidability, mode of action and risk potential of air leaks in the building envelopes of heated buildings could be meaningfully applied under civil law, taking into account the conflicting interests of industry, building contractors and developers.


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