My parents’ neighbours have tanked my mom and dad’s external retaining wall without my parents’ permission. Deeds clearly state it is my parents walk. My parents live above them on a slope so there is a retaining wall for the soil and earth below my parents house with a damp proof course about a metre up the gable end wall. They have tanked below and above the damp proof course with grey paint against their red brick wall. This is in effect an external wall and the bricks can no longer breath allowing moisture out from the wall naturally and that the bricks may end up water logged, during cold times expansion and contraction of water freezing in the bricks may cause damage to and weaken the bricks and hence destabilise the entire end wall. I don’t know what tanking above the damp proof course could cause internally - eg could it cause condensation and hence mould and damp underneath. Sadly they refuse to remove what they have done and have signalled their intent to tank the rest of the wall even though it is not their wall and they have no right to touch the wall. As a result I am having to research the impact in order to consider more official remedies.
Many thanks