Dampness in bricks reduces insultion by a factor of about 50%, so even if the rain doesn’t actually penetrating through the wall, the increased susepticibility of one a section of wall to become damp, reduces internal temperature increasing the risk of condensation and mould. A good example is where the uppeer section of wall is painted or render, and the lower section exposed, resulting increased dampness on the external skin causing bricks to lose heat..
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Mode details are being uploaded regularly, towards the end of every month.