Shrinkage tests for a jointless 24.4 m long carbon concrete shell – approval procedure for the TWIST shells. For the construction of the carbon reinforced concrete house CUBE, extensive investigations were necessary as a prerequisite for obtaining of approvals in individual cases (ZiE) and project-related type approvals (vBG). Material parameters of non-regulated building materials, new areas of application of already approved building products and non-standard construction methods were regulated. In the first part, we explain how the shrinkage values of the concretes for the load-bearing and weather shells of the TWIST elements were determined. The second part deals with the shrinkage behavior of two 24.4 m long slab strips that represent a section of the equally long TWIST element. The investigations allowed for predictions about the deformation behavior of the carbon reinforced concrete weather shell. Based on the values measured experimentally or determined by model calibration and finally recorded in the ZiE/vBG, the deformations of the carbon reinforced concrete shells in the serviceability limit state could be determined realistically by calculation. The values were so low that the shells could be produced on site without joints.