Hi, I have a shower room which is fully tiled, floor and walls. There must be a problem on the one side as the wall on the other side is damp and the plaster is coming off up to 30ins from the floor. They are large wall tiles on the shower wall and only the one wall appears to be affected. the only thing I can think is the grouting on the bottom joints are leaking, any ideas please about sealing them, thanks.