A wafer construction (200) for applying a collecting system (100) around an ostomy, the wafer construction comprising a central through-going aperture (201) for bringing the ostomy (001) in fluid communication with a collecting reservoir (300), an inner radially extending layer (220) for attaching the wafer to the peri-stomal skin (002), said inner layer (220) comprising a skin contacting surface (221), a moist vapour permeable layer (224), an outer surface (226)； an outer radially extending layer (230)； said outer layer comprising a substantially moist vapour impermeable film (232), an outer surface (236), an inner surface (238), a bag element (234) for engaging the wafer (200) to a collecting reservoir (300)； a central stoma-adjacent-area (240) comprising a first area of both the inner layer (220) and the outer layer (230)； said central stoma-adjacent-area defined radially as the area of the wafer construction (200) closer to the central through-going aperture (201) than the bag element (234) of the outer layer； an encircling area (250) comprising a second area of at least the inner layer (220)； at least one radial space (270) in fluid communication with the atmosphere (500)； said radial space (270) being located between the outer surface of the inner layer (226) and the inner surface of the outer layer (238)； and at least one attachment point (260)； said attachment point attaching the outer layer (230) to the inner layer (220)； wherein at least a portion of the radial space (270) is located in the central stoma-adjacent-area (240).
