Hybrid application of conventional concrete and Strain Hardening Cementitious Composite (SHCC) is recently shown to be promising for crack width control. In this paper, a combined experimental and numerical study is performed to validate the concept and to study the effect of interface treatment on crack width control. The interface is varied between smooth, profiled, partially debonded and completely debonded surfaces. The beams are tested under a four-point bending configuration. The crack development is monitored using digital image correlation throughout the loading, and maximum crack width of 0.3 mm at the surface is taken as the limiting criterion for analyses. The hybrid and control beams are simulated using the lattice model. Both experimentally and numerically, it is observed that stronger interfaces enable the composite action in the hybrid beams and provide better crack width control compared to the artificially weakened interfaces.@en