A steel external window sill should be considered as part of a complete detail, not just a sheet of metal. The building owner and the trade should check whether the light form, dimensional fit and consistent colour go hand in hand with a slope, stable support and ends that drain water away from the façade. The article discusses five advantages of this solution, but also shows the limits of their operation: the sheet is not a platform or a universal shelf, and its durability depends on the coating, installation and later care. The choice of variant should take these dependencies into account.

Unusual flashings allow areas not covered by the standard catalogue to be finished. However, they must be feasible to manufacture, deliver and install. The drawing should take into account not only the visible shape but also the actual substrate and the sequence of works. With sandwich panels, their locks, profiling and layer connections are additional factors. A good detail combines this information before production begins. First, establish what the flashing is to cover and where it is to direct water. A cover for a vertical joint is designed differently from a drip edge, and differently again from a capping. A similar letter outline does not determine the same function. The drawing should also show adjacent elements.

Glass-fibre reinforced laminate cladding is considered for buildings exposed to moisture and aggressive environments. Its advantages only become apparent in a complete solution, however. Where frequent washing takes place, joints, flashings and the cleaning method are equally important. A panel's resistant surface does not make the whole building immune to operational errors. Before choosing cladding, write down what the interior will be cleaned with and how. The names of the preparations are needed in the technical documentation, along with concentrations, water temperature and contact time. Separately record whether the agents will be rinsed off and whether the room can dry after washing.