||Network-based space layouts are fine-grained models of architectural spaces. Potential application domains include but are not limited to building services. In previous work, a schema for network-based space layouts was introduced. The schema consists of two complementary subschemas: a layout element network and a geometry schema. A layout element network represents layout elements and topological relationships between them. It facilitates queries such as shortest path or nearest neighbor queries, which are useful, for example, in indoor navigation, lighting control, or climate control applications.This paper examines two related issues concerning the consistency of network-based space layouts. Addressing these issues completes the schema design and provides a robust foundation for the development of applications which use network-based space layouts.First, how can the consistency of a network-based space layout be checked, both with respect to itself and the represented architectural spaces? For example, the layout element network and geometry data associated with layout elements may be inconsistent, or certain layout elements may overlap although their real-world counterparts do not. Unfortunately, these inconsistencies may not be detected by evaluating structural constraints implied by the schema alone. Additional constraints are thus required. Constraints are defined which are based on topological relationships derived from geometry data.Second, if a network-based layout has been found to be inconsistent, how can it be converted to a consistent one? This conversion is referred to as refinement. It involves the evaluation of the aforementioned topological constraints to recreate the layout element network and certain layout element geometries. As a result, layout elements and relationships may be added, removed, or left unchanged.The paper concludes with a discussion of the applicability of the described topological constraints in other building models.