The starting point of this design was a 1925 Basel apartment building that was extended by two storeys. An essential principle of construction were two ridge beams braced between the compartment walls. They enabled a suspended roof construction in prefabricated wood.

Two symmetrical maisonette apartments were created with a variety of spatial qualities determined by the construction. The enclosed sleeping accommodation is thus on the upper storey while the outer-facing living areas are on the lower level. The staircase serves as the central element which connects the open and closed spaces in a double-height chute with a centred skylight. All the interior finishes respond to the wooden load-bearing structure. The wooden construction remains visible in its final state and thus contributes to the atmosphere in these spaces. An important design quality of the roof extension is the way in which the structure and materials combine. Spaces with dynamic visual connections, offering high-quality living, have resulted.