The Natural Philosopher wrote:
Phil L wrote:

Water runs down the inside of your exterior brick/stonework during
heavy rain...

It bloody well should NOT. If it is you have a serious problem.

Or airbricks...


Whether it should or it shouldn't is irrelevant, and on some walls it will
while on other walls...you get the picture, it all depends which way the
wind blows, how many cracks are in the mortar (quite a lot in most houses,
even new ones) and a hundred other factors, none of this is a serious
problem though, until something blocks the water's natural course and it
gets where it shouldn't.