In 2004 the residential box "Haus Lina" was built next to an existing house. THE PROVISORY AND CONSTRUCTION EXPERIMENT... Infrastructurally and constructionally "docked" to the old building, the structure already contained all primary functions such as bathroom, kitchen, heating and hot water preparation. The construction grid of the building structure was designed to the delivery dimensions of the rough particle boards, the overall construction in lightweight construction with mineral insulating material. This allowed the partially prefabricated elements to be placed on the steel girders, which were connected at points with strip foundations. The small building was wrapped with a truck tarpaulin. The wrapping construction, which was approved as a waterproof panel by the physical building planning department, was not without problems, but since the building was deliberately not designed "for eternity", the building, which was deliberately designed as an experiment, was risked. The house could be easily removed or extended depending on the future living situation. BECOMES A PERMANENT SOLUTION – in 2020, after the family had grown, the small residential unit was extended and upgraded; this time with prefabricated timber frame wall and ceiling elements filled with recycled insulating material; the truck tarpaulin was removed and replaced by a diffusion-open underlay; a corresponding rear ventilation level was installed over the entire structure. On the south side, a covered terrace was added; the canopy provides shelter from the sun, only in the winter months direct sunshine brings heat input.