The Visitor Center at the Great Sand Dunes National Park and Preserve was originally built in 1960 and underwent various additions and renovations, with the latest addition built in 2003. With the advances in building science and material technology between 1960 and 2003, there were areas of the building envelope in need of repair to maintain a continuous air barrier. Pie conducted baseline diagnostic testing and provided detailed repair recommendations based on the as-built drawings from each phase of construction. Following completion of building repairs, Pie re-tested the building to confirm the efficacy of repairs. With Pie’s diagnostics and recommendations, the building’s air leakage was reduced by 15% and contributes to the overall increase in energy efficiency of the building.