St. Michael's Church in Leonberg-Eltingen has a late gothic net vault showing substantial damages. For a structural stabilization the extent of the damages as well as their causes had to be found. As basis for a deformation analysis precise measurements of the vault and the surrounding walls had to be taken. Using a grid of fixed points all details were measured with a reflectorless laser system. The measuring devices, the measuring procedure and the measuring results are described and discussed. The interpretation of the measurements such as foundation settlements, wall inclinations, vault deformations and translations in the roof structure is combined with a technical and historical analysis. Finally the concept for the structural stabilization is presented.