how can i stop water saturation on outside stairs?

Sounds like you have water penetration coming off the treads into the wall.You need to stop any water sitting on the treads from soaking into the brickwork - go out on a wet day and see if any water is sitting on the treads or maybe running through open joints then you know where to seal. Let it dry and start by pointing up any cracks with mastic - it needs to be flexible because stairs always seem to move relative to the building causing cracking.You could seal over the joints with a flexible roof sealant such as "acrypol" but it is messy if you are not used to handling it!!. Also you could put a couple of airbricks or vents in the outhouse to help dry it out. Good luck

Barry
February 2009