## 3 Results
### Results from the Rain Infiltration Test  
The results of the relative humidity measurements in the mineral wool during the rain infiltration test are presented in Figure 6. The conditions during test are presented in Figure 7. Average values in the climate diagram are indicated with numbers. The result figures include vertical lines to indicate the duration of the test phases. Phase one, with a recurrent leakage moisture load of 6.9 g, lasted 22 days. Phase two, with a recurrent leakage moisture load of 20.7 g, followed phase one with a duration of 40 days. The final, phase three, with no leakage moisture lasted 47 days. The leakage events are indicated as dots in the lower part of the figures. The form of the relative humidity curves was similar for all wall types in the middle height of the frame, on the cold side of the wall (Figure 6a). However, the changes during the water leakage event were significantly larger for wall HI1; the relative humidity jumped from 60-80%, whereas for the other wall types this change was typically below 5%. Wall HI2 has a more vapor-open PA-foil vapor barrier, whereas HI1 has a PE-foil vapor barrier. Walls HI3 and BL have hygroscopic gypsum board against the cavity insulation, whereas wall HI1 has wb-mineral wool with low hygroscopicity at that point. These differences might affect the changes in RH in the short term. For the baseline wall the relative humidity varied between 70-80% and for the HI walls between 55-70%, disregarding the peaks for the HI1 wall. The R-value of the structure outside the wood frame is remarkably lower for the BL wall than for the HI walls, which affects the RH levels through occurring temperatures. During phase two, the average relative humidity in the HI1-HI3 walls rose from 60-65%. This implies that the leakage moisture amount of 20.7 g was high enough to surpass the moisture retention capabilities of the materials affected by leakage. For the BL wall the change in the initially higher RH level was minimal. With higher initial relative humidity, the BL wall has a higher slope in the hygroscopic moisture curve of the gypsum board. Thereby, excess water from leakages is absorbed by the gypsum. In phase three it took roughly two weeks for the HI walls to reach the same RH levels as before the leakage test. This implies that the structures had a high drying ability against moisture loads from rain infiltration. The RH level in wall HI1 was 3-5% lower than in other HI walls, which was also observed in the built-in moisture test. The reason for the RH difference might be connected to the hygroscopic gypsum board in wall HI3 and the PA-foil in wall HI2. A closer look at the RH curves in the middle height at the cold side of the frames during phases one and two (Figure 6e,f) revealed that, in wall HI1, a moisture leakage of 6.9 g took 19 h and a moisture leakage of 20.7 g took 45 h, on average, to return the RH level near to the values before the leakages. For the other walls the return times were similar, although the changes in RH were substantially lower. Figure 6: (**a–c**) relative humidity from the middle height of the wood frame during the leakage test; (**d**) additional measurement points were located 5 cm upwards from the bottom of the insulation; (**e**,**f**) an example of relative humidity change during small and large leakage events. The RH results are shown until 18 December 2018 because significant RH level changes were not observed afterwards. Figure 7: Climate conditions (T/RH) during the leakage test. The warm side of the wood frame in the middle height (Figure 6b) had a relative humidity between 27-32% for the BL wall and 32-49% for the HI walls. Water leakage generated peaks in HI walls, but not for the baseline wall. This implies that the gypsum board in the BL wall moderated the RH changes in the warm side of the frame. The RH peaks were possibly evened by the PA-foil in wall HI2 and the gypsum board in wall HI3. In phase two, the average relative humidity rose in the BL wall from 29-31% and in the HI walls from 35-41%.