The objective of the extensive experimental investigations at the exterior wall-floor joint on a scale of 1:1 on highly thermally insulating clay unit masonry was to record the interaction between the acting axial force and the resulting slab rotation as a result of defined slab fixed end moments. The focus of this test series was on the influence of the nonlinear system behaviour at different axial force-moment combinations caused by the gaping of the horizontal joints as well as the contact zone between slab and masonry. With knowledge of the moment-rotation interaction as a function of the axial force of the wall, a numerical model can be developed with regard to the nonlinear system behaviour. Since the angle of rotation of the slab is of major importance in this respect, the structural design of a reinforced concrete slab is dispensed with in the test and replaced by a flexurally rigid solid steel bracket. This has the decisive advantage that the rotation of the steel bracket can be precisely detected by means of optical deformation measurement (digital image correlation) and directly assigned to the existing axial force-moment combinations. The evaluation of the tests has shown that the dominant nonlinear effect is essentially due to the gaping of the horizontal joints in the exterior wall-floor joint. During the test execution, the proportionality limit between the bracket moment and the bracket rotation could be successively increased with increasing load level regardless of the previous nonlinear system behaviour.