In the same way small details have a large impact on simulated energy use, small architectural details can affect the energy use bottom line by compromising the envelope's thermal properties. Two-dimensional heat transfer analysis and fin heat transfer formulas were used to study thermal bridging in the balconies at the east and west ends of the RSF. A detailed 2- D heat transfer model was used to derate the U-values of the constructions used in the energy model for the whole-building energy model, to investigate design strategies to minimize the bridging, and identify likely areas of problematic condensation. Areas initially studied included the connection of the superstructure to the substructure and balcony attachment points. In all cases the design-build team adopted mitigating measures. Later this analysis was used to evaluate the insulation required between the radiant ceiling slabs and the adjacent supply air floor plenums and prove the necessity of avoiding a specific standard detail for mounting photovoltaics (PV) to the roof. This drove a complete change of the roofing system to a standing seam strategy to avoid penetrations. The standing seam structure was affixed to the roof membrane; the funds came from the project contingency.