Painting & Decorating

Damp coming through on smooth rendered garden walls which we are wanting to paint.

Anonymous user 16/03/2024 - 2.50 PM

I previously posted similar question. I had really good input back but this platform does not allow you to clarify anything once initial post is up so I was not able to get final advice. To summarise: We have had garden walls built (about 6' high) which extends the width of our back garden and the sides. The walls were built on proper foundations and standard concrete breeze blocks were used which were then smooth rendered on the house facing side (water proofing formula was using on the scratch coat). Every time it rains you get what appears to be wet patches appearing through the smooth render (patchy in different places). There is coping on the top of the wall. I plan to paint the walls with a decent under coat and then a decent external final coat. It is not raising damp as it is patchy wet marks which come through when it rains, a lot above the half way mark. Although the block work is very tidy on the house facing side of wall which you see I have looked behind the wall and from the back of the wall the cement has not been properly scraped away so it sits out. I am not a builder but I am thinking the water is finding its way through the wall from the back; possibly when it is hitting the cement. Any thoughts on how I can resolve this ? We spent a lot on the walls and want to make sure the final finish paint job (when we come to do it) remains good. Thanks in advance (and thank-you Mike Anthony for your previous input)