1. Next time it rains make sure your rainwater system is working properly. Check that your guttering is aligned to run slightly downhill towards the downpipes, that all brackets and joints are properly attached and that the gutter is not blocked or sagging. Make sure your downpipes are not blocked and over-flowing, that the joints don't leak and that the pipes are not damaged.
2. Sometimes a dripping overflow pipe can wet the masonry. Hunt down your overflow pipes and make sure none are dripping. Generally you will have one for each toilet, one for the central heating header tank and one for the cold water storage tank. Dripping will almost certainly be the result of a fault with the float valve in the relevant unit.
3. Check any other pipework fixed to the outside of your home for damage, blocks or leaking from a joint.
4. Check the brickwork for signs of repeated wetting. If part of the wall seems discoloured or stained, look for the cause. Most houses have a damp-proof course at least 15cm above ground level and faults in this may allow water to soak up from the ground into the wall. It is also possible for the damp-proof course to be "bridged", for example by soil heaped over it. Look around the base of your walls and move away anything that might allow moisture to soak into the wall or anything that might allow rainwater to run onto the walls.
5. Check the condition of the masonry, that the mortar is even and in good condition not crumbling to leave deep gaps into which water can seep.Reuse content