Driving rain tightness and defects of prefabricated concrete sandwich walls with joints, windows and balconies

There have historically been, and still are, problems with water intrusion into new external walls of prefabricated concrete sandwich elements in Sweden to a varying extent. The aim of this study was to obtain documented knowledge and data on driving rain resistance, to provide a basis for improvements and calculations in a common kind of concrete sandwich system with fa & ccedil;ade components and sealing products. The study included inspections and air pressure difference measurement of fa & ccedil;ades in the field and driving rain resistance testing of experimental set-ups in a laboratory. Inspection showed that vertical joints between the concrete elements were often significantly too narrow and, at the same time, adhesion loosening of building mastic in these joints was common. TDV-tubes were often incorrectly placed or had a bad incline. Field measurements indicate no pressure equalization, which is also confirmed by lab measurements. Lab results indicated inward leakage at window-wall interface, even without wind pressure, through the TDV-tubes despite a sharp incline, in element joints with a new kind of application of pre-compressed joint sealing tape. The largest leakage flows were of 0.4% of the vertical water flow across a unit width of the fa & ccedil;ade at the given height.