Type IX Expanded Polystyrene rigid insulation was used to insulate the foundation and concrete floor slab of this transportation facility near Four Corners, CO. The 1.8 lb density EPS insulation was used because it provides the most economical R-Value of any comparable rigid insulation material. The 4” thick EPS insulation panels have an R-Value of 17.4. The seams were taped to limit air infiltration. 284 panels were used to complete the project