Construction processes intensively contributes to greenhouse gas emissions worldwide. The resulting climate change affects historic buildings and complicates built heritage preservation. However, there are several actions under way, such as the European Green Deal, to reduce CO2 emissions in construction. Revaluation of existing structures under application of recycled materials and by re-use of available building elements may save resources and thus reduces emission of CO2 in construction industry. This contributes to a more environmentally friendly construction process. Furthermore, re-using of existing building materials or elements may preserve the historical appearance of structures, in the interest of future generations. For production and usage of new building materials and elements, a plethora of legislation and codes needs to be considered. The same applies to re-use of existing building materials and elements which increases the danger for construction defects and thus expensive claims. Thus, beside the advantages, re-using of building materials and elements bears risks to all stakeholders in a construction project. In the interest of avoiding conflicts between the construction contract parties, a legal risk analysis is necessary to support them in decision about the re-use of existing building materials and elements. The authors examined current international, European and German law, codes, and policy dealing with re-use of building materials and elements. Furthermore, they reviewed existing literature about that topic and analyzed relevant court cases of the last twenty years. The conclusion is, that there is a need for a detailed contract specification which kind of existing building elements and materials can be re-used and who takes the responsibility for known or unknown defects under the aspect of liability. The paper provides suggestions under which legal aspects a re-use of building elements may be recommendable and which requirements need to be met.