We have a wall that had been treated with sika render before we bought our house. Fast forward 9 years and the render is still working but the chemical barrier at the edges of it seems to be failing and now the adjacent walls are damp. We need to get it fixed. Does anyone know how long sika render should last? I'd like to know if we've been unlucky or if it only has a life span of 10 - 15 years. If so, would a pumping system last longer?