This paper describes an approach for reasoning about the repairability of workflows at design time. We propose a heuristic-based analysis of a workflow that aims at evaluating its definition, considering different design aspects and characteristics that affect its repairability (called repairability factors), in order to determine if the workflow schema supports repairable executions of its activities through the application of repair actions. The analysis intents to identify and evaluate the impact of critical design flaws affecting the repairability of workflows. The results of this analysis are fed back to the workflow designer and used to improve the repairability of the workflow by making appropriate changes to its definition.