I have a 1930s house, which I've lived in for 2 years. It was rendered, I'm guessing at least 20 years ago. In the last few months I've noticed that in one (south east) facing wall the bricks are showing through the render (you may be able to see in the photo). This has definitely not been an issue before this year. There's no new cracks or anything of note that could have let water in, so I'm just wondering why it would suddenly happen, and also whether there's anything I can do? If I painted it, would it show through?