This study is to determine the impact of spatial configuration on the level of functional efficiency of house layouts in Erbil city in Iraq, from 1900 to 2010. Erbil city in Iraqi Kurdistan region is selected as the case study because the city has mixed styles of traditional and modern architecture. The period from 1900s to 2010s in this study is not coincidental, selected for the analysis because during this period, its architecture experiences the most rapid changes with an influence of modern architecture superseding over the traditional architecture, where this condition is not found in the earlier period. The literature study comprises two parts. The first part is a theoretical study of the relationship between spatial configuration and functional efficiency of the house layouts highlighting the key syntactical characteristics of spatial configuration and its impact on the level of functional efficiency, based on the Theory of Space Syntax in clarifying this relationship. The second part is an overview study on house layouts in Erbil city through an analytical-comparative description to the changes and transformations in their configurations; classifying the period (1900-2010) into four time periods with about 30 years’ sequence for each period (1900-1930, 1930-1960, 1960-1990 and 1990-2010s) with reference to the historical events which influence their layout designs, categories of the house layouts, types, patterns, and zoning of spaces and activities. This analysis description to the stages and periods of house layouts reveals differences and changes over time. The main benchmarks and indicators that contributed in measuring the functional efficiency of house layouts are the Mean Depth of space (MD), the Real Relative Asymmetry of space (RRA), the Difference Factor of space (H*), Space-Link Ratio (R-Ringiness of space), and the Space-Type (the degree of spaceness). These indicators are analyzed using the Space Syntax’s Theory by applying a software program, Agraph-2009 which provides numerical results. This analysis compares entire samples of the house layout designs for each period. These numerical results indicate the impact of spatial configuration and functions of the house layouts. The result shows that house layout changes over time due to the process of spatial configuration and its functions. The second period (1930-1960) has the most efficient house layout with most of the mentioned indicators that applied in the process of evaluation, with numerical results 2.936 for MD, 1.012 RRA, 0.896 H*, 100% Ringiness of space, and 0.382 the degree of ‘c’ and ‘d’ types’ spaceness. The result supports the research hypothesis which assumes that the functional efficiency of the house layouts is affected by the process of spatial configuration over time. The research contribution is that analysis using the Space Syntax’s Theory contributes numerical results to support the hypothesis by indicating the level of efficiency. It guides towards innovative approach with tangible results for references in the future development of house layouts in Erbil City.
