Refurbishments or even conversions present particular challenges in existing structures, as intervention in the structural system is not necessary without sometimes considerable ancillary work, such as shoring and underpinning. Here, the encasement of columns and other statically relevant components with the ductile, micro-reinforced high-performance concrete offers an economical alternative. Column sheathing has already been implemented on various high-rise buildings, on production facilities in earthquake zones and also on a bridge structure. The thickness of the reinforcing sheathing was between 50 and 100 mm, depending on the structural requirements.