In situ Performance of Expanded Molded Polystyrene in the Exterior Basement Insulation Systems (EIBS)

Several different Exterior Basement Insulation Systems (EIBS) were built and instrumented as part of the basement consortium 2 research project. These EIBS specimens were instrumented prior to back filling with soil, and their in situ thermal performance was monitored over two years. Soil temperatures and moisture content were monitored concurrently. Weather data were recorded on a daily basis. Through analysis of the measured surface temperature records, the presence of water was detected at the outer surface during various periods of heavy rain and major thaws throughout the two-year period. During these periods, the surface of the concrete showed no evidence of water penetration through the insulation layer over most of the height of the basement wall. Since the test setup involved different thermal insulating materials placed next to each other, the presence of lateral heat flow was inevitable. Both 2-D and 3-D models were used to quantify the lateral heat flow across the edges of different in sulating materials. The measured spatial and temporal temperature profiles were used as boundary conditions. The thermal performance of each insulation specimen was found to remain sta ble over the two-year period and was not significantly affected by episodes of wa ter movement at the exterior face of the specimens. The thermal resistance of