Reviving neglected existing urban fabrics is one of the main frame-work for our future. A contemporary theory of conservation regarding architectural intervention and buildings subsequent re-use, has been developed to address a growing number of tired and neglected buildings. Rehabilitation is required for buildings that are no longer fit to purpose and struggling to adapt a new use. The Spatial Openness Index, is a visibility analysis model defined as the volume of the visible part of a surrounding sphere: the potential of a view and exposure that can indicate on the Perceived Density. Using visibility analyses models and tools, regarding internal space layout, in reinterpreting the functional use of existing buildings would contribute to future refurbishment and reviving urban fabrics. In this paper, a study of the relation between internal space layout and functionality and external visual analysis is suggested. The study is demonstrated on a neglected Haifa neighborhood.