Plug-In is a flexible model that can be superposed to a wide range of existing buildings. Dismissed warehouses, malls, old industrial buildings have often oversized structures and vast flat roofs that can well support few more new floors. The vertical connections (stairwells and HVAC shafts) are organized as independent new elements, hence the Plug-Ins are fully independent structures, acting as benign parasites to the present city fabric.
The modular housing units are fully open towards the exterior (to maximize views, sitting on top of other buildings), while the opposite side looks towards the inner courtyard or the walkway with shared facilities. The walls between units are CLT bearing walls, that support Kerto Ripa flooring system. Light walls are made with Kerto T LVL elements.
The case study in the picture below is Ympyrätalo in Helsinki city centre, a well-known mixed-use building from 1968.