mortar stains

Hi All - Bought a house with lovely white painted rendered garden walls with York stone caps. Every cement joint between the stone caps bleeds horrible dirty brown stains down the walls. How do I stop this from happening? Repainting lasts a month, if that. As you can see, these walls have fence...

Hi all, I have a wall that is above a flat roof extension, the flat roof is felted and gravelled, I have to remove some very poor mortaring from the brickwork, the mortar will eventually need removing as it is a different colour to the rest of the mortar but for now all I have to do is remove...