Modern buildings typically contain envelope systems that require specific layers to control condensation due to moisture migration and/or air leakage, dedicated waterproofing systems to protect moisture-sensitive backup materials (e.g., wood and gypsum-based products), and thermal insulation to control heat losses and gains. Consequently, building codes include provisions for these systems in new construction, and in some cases, renovation projects. As such, architecture and consulting firms frequently turn to hygrothermal modeling to determine the optimal arrangement of these layers. This presentation will introduce the parameters to consider when setting up a model, and through several project examples, demonstrate how hygrothermal modeling can be used to develop assemblies with a low risk for moisture-related problems. Also, critical to the process, we will touch on some of the limitations and assumptions made when developing a hygrothermal model.