Damp patches on outside walls

[pinwillow]

Between the side of my house and the garage is a covered concrete walkway so the wall is shielded from rain. For a few weeks I have noticed a damp patch down from the DPC to the concrete which appears to be drying then re-appears. I have checked the inside wall with a damp meter but it is completely dry.

A couple days ago the damp patch appeared looking very damp and the stain had spread onto the concrete path. Also four further damp patches appeared along the wall and the furthest although below the DPC and the other side of the back door frame the patch was not down to the ground.

Although the DPC apopears to be doing its job I believe that I will have to take action on it. There is a waste drain below the concrete but it is clear. Before I extract a brick at the original damp patch to check out the internal situation do any of you experienced members have any suggestions as to what the cause may be.

Thank you

[ultimatehandyman]

It's difficult to say without seeing it, even then it can still be difficult to diagnose what the problem is.