Esker House (esker=stratified geological formation) is a self-contained residential unit placed on top of an existing house from the 1960s. Initially developed as a parasite which started from adopting the host structure and gradually differentiated into its own unique organization, formed by a series of steel and timber frames that deform to recreate the hillsides of the surrounding dolomites. This partly accessible roofscape also determines the spatial character inside -the spaces are enfolded by angular series of planes. The morphology and construction-system started off from projecting each step of the external staircase as a modulor that then was proliferated as frames. The split-level leads to the lengthening of parts of the stairs to form a topography for informal occupation. The overall character is that of an echelon with a diffusion of functions where inside and outside, above and below become zones of varying intensity.