Mobile augmented reality devices for indoor environments like the Microsoft HoloLens hold potential for the in-situ visualization of building model data. While the HoloLens has sufficient real-time inside-out tracking capacity to provide a spatially correct and stable visualization of virtual content relative to its surroundings, the placement of virtual objects normally has to be done actively by the user. Beyond reliable tracking capacity, augmenting an indoor environment with corresponding building model data requires a one-time localization of the AR platform inside the local coordinate frame of the building model to be visualized. To this aim, we present a simple marker-based localization method for the HoloLens that is sufficient to overlay indoor environments with virtual room-scale model data with a spatial accuracy of few centimeters. Furthermore, an evaluation method suitable for the proposed scenario is presented, that does not rely on the HoloLens “Live Capture” camera which turned out to produce deviant placements of virtual content in relation to the perception of the user wearing the HoloLens device.