International audience Widely disseminated by François Cointeraux publications in the 19th century, « pisé » or rammed earth can be found in many european plains such as Vojvodine in Serbia, South Portugal, Piemonte in Italy and Saône and Rhône plains in France, last of which is where François Cointeraux initiated his discovery of this technique. Rammed earth heritage in and around Lyon is therefore one of the richest in Europe, still very present especially in rural areas, however it's endangered since decades by inadequate and sometimes dangerous interventions : retrofitting and repairing techniques used are mostly conventional building techniques. Trainings for building professionals including earthen materials and heritage, although developing, are still very rare. People who want to preserve their heritage therefore have to choose between rare competent professionals or learning and self-‐ building. As professional involved in rammed earth heritage retrofitting and assistance to self-‐ builders since half a dozen year, it felt necessary to be in the self-‐builder situation, so as to face first-‐hand the questions raised by retrofitting rammed earth heritage. A ruined rammed earth building in a village near Mâcon, along the Saône river, was therefore acquired and a project set up to explore the use of local resources as building materials. This paper aims at presenting the process, describing some of its technical aspects and drawing some first lessons