IMPROVEMENT OF THE WATERPROOF PERFORMANCE ON THE PLASTER ON INSULATION SYSTEM

We propose a method for testing the drainage performance and waterproof performance of the structural part of a wall in the external insulation, and a method for reducing the risk of water leakage by cutting drainage grooves on the insulating material, and show its performance by full‐scale model experiments and laboratory experiments. The research results are summarized below. 1) Full‐scale model experiment on drainage performance The outer wall of the outdoor experimental building was used to clarify the behavior of infiltrating rainwater on the back of the EPS external insulation wall. In order to examine the effect of the presence or absence of the drainage layer on the drainage performance, the walls where the grooves were cut on the back of the EPS and walls without the usual groove were tested at the same time. Red colored flush water were injected into the wall installed in the experimental building, and the drainage performance was confirmed visually. The obtained findings are as follows. ・ For the drainage condition of the whole, there is a specific water channel in the grooveless wall and drainage is concentrated, but in the grooved wall, it was possible to disperse in the drainage and avoid partial concentration of the flow. ・ It was found that the flow was blocked in the grooveless wall, especially at the lower end because of the drainage condition of the wooden horizontal base. In the grooved wall the flow was blocked, but it drained smoothly. ・ At the longitudinal joint of the grooved thermal insulating material, the water was retained, and it is considered necessary to study the shape of the groove to further improve drainage. 2) Labo test on waterproof performance We made a full-scale wall following the plaster on insulation method and tested drainage performance. The effectiveness of the drainage groove was confirmed by comparing the grooved and non-grooved test results. The waterproofing performance test was conducted according to the JIS standard, and the method for testing the waterproofing performance of the plaster on insulation was established. The obtained findings are as follows. ・ In the experiment without pressure, after 1 minute 27 seconds, water leaked from the window top to the internal wall, and after 6 minutes 38 seconds water also leaked to the internal wall from the lower end of the wall. ・ In the experiment in which pressure was applied, leaked water from around, the screw and above the window to the interior at a pressu