This paper deals with the problem of requirements interaction. We introduce a three level framework to detect requirements interactions at different levels of cost, time, and complexity. Level 2 where we use semi-formal methods to detect interactions contains the main contribution of the research. Also we combine already existing approaches (e.g. informal and formal) with our semi-formal approach to provide a comprehensive framework for developers to use. The approach is illustrated using two case studies, one from the telecommunications domain and the other one being a lift control system. The results obtained are very encouraging with regards to the time and effort spent on requirements interaction detection.