Study on Bond Strength of External Thermal Insulation System with Perfusion Polyurethane Foam

External thermal insulation system (ETIS) is an important part of building energy efficiency. Polyurethane foam as a superior external insulation material was analyzed in this paper. The variation law of bond strength of the ETIS with polyurethane foam was studied by atmospheric exposure tests which consist of two stages including high temperature-spraying water cycle and heating-refrigeration cycle. The results show that its bond strength declined lightly with time increasing and its value is always greater than specified value. Therefore, the ETIS of composite perfusion polyurethane foam has better weatherability and it can adapt the various inconstant weather conditions. By comparing the bond strength curves of the three kinds of popular ETIS of expanded polystyrene (EPS) board, polystyrene granule mortar and polyurethane foam, the result shows that the downtrend of bond strength of composite perfusion polyurethane foam ETIS is gentlest, thereby the weatherability of polyurethane foam ETIS is best among the three ETIS.