Weatherability studies on external insulation thermal system of expanded polystyrene board, polystyrene granule and polyurethane foam

Atmospheric exposure tests including two experimental stages of high temperature-spraying water cycle and heating-refrigeration cycle were carried out on three currently used ETIS of expanded polystyrene (EPS) board, polystyrene granule mortar and polyurethane foam in order to study the weatherablility of external thermal insulation system (ETIS). The change rules of adhesive strength were hereby studied at different time period of atmospheric exposure tests. The experimental results show that the adhesive strength of three kinds of ETIS changes a little during high temperature-spraying water cycle, but the adhesive strength of ETIS with EPS board decreases significantly after heating-refrigeration cycle. The lowering rate of adhesive strength with painting finishes is obviously faster than that of tile finishes for ETIS of EPS board during heating-refrigeration cycle. The weatherability of ETIS with EPS board is worse than the other two, and ETIS of polystyrene granule mortar and polyurethane foam are more suitable than ETIS of EPS board in cold area.