Who to Ask - Cause of Damp

Hi There are two types of damp: Rising damp which you would find on the ground floor and only comes up a wall 1m. The other is penetrating damp.You have penetrating damp.If it’s on the corner, is there a hopper that your gutter runs into via a short section of pipe? If so, check the hopper isn’t blocked.An obvious fault but common. Also, again, check your gutters are clean and they haven’t become full of debris and the rain filling them up isn’t running over and down your wall. For the wall to get that wet, one would have to assume that water is running down the cavity. Equally, one would assume a competent roofer would check all of these obvious points. Hope this helps Mark Trowel Craft Leeds

Yes as above. Check all guttering detail including behind the hoppers, check pointing for holes in stonework or block work , check for hairline render cracks. Has the wall been cavity insulated? What finish are the walls internally? Board? Skim? Or....bonding?

If it's a chimney wall its it's possible that you have salt damp. Salt damp is contamination from burning fossil fuels over long periods. These salts are chlorides and nitrates (ammonium salts), these salts are hygroscopic salts and will readily hold and retain atmospheric moisture. Hence heavy rains, stains more prominent .

Damp can be problematic the fact in dries back when it not raining seems to suggest it's weather related . If your roof is sound following a 're roof I suggest u get them back to check and while they are there check the gutters, fascia boards. There is a possibility condensation plays a part but not if the problem improves when it's dry. If the weather is dry but cold outside I would observe whether the problems remains the same or worsens in which case I would be looking at cold spots between roof and walls. The ramos needs testing to make sure it is actually reading damp not just looking damp. For this I suggest u call a damp specialist like us. Good luck!

Two types of dampness have already been mentioned but typically the third type has been left out, mainly because so few know about this ! It’s called hygroscopic dampness , typically wetter when it rains and dries a little when it stops raining . If there is a chimney involved , even if it has been removed , hygroscopic salts remain and display the exact symptoms you describe ; also if plaster ( not render) is more than 2.0mm thick , it can also look like that .