Have removed wooden beams from the outer wall in the basement. I will also remove and brick up a basement window this weekend. I plan to finish by applying a thin render over the entire surface and then paint with silicate paint. Drained and insulated with pordrän.
Do I need to sand off the paint currently before the thin render? I really want to avoid that. I will, of course, remove all loose material regardless with a regular scraper.
Can you roll on any primer if needed to increase adhesion?
I did a whole room a while ago, but there the render was porous in many places and the paint flaking, so I sanded everything down first, which was a hell of a job. Here, the render is rock hard and the paint is not flaking nearly as much.
Scraped the entire surface with a paint scraper just so that the loose parts came off (like the bubbles seen at the bottom of the image), which also meant some of the paint peeled off. In my case, I didn't use a flat blade but a wavy one, which allowed me to easily scrape down to the plaster. As seen in the image, the paint is extremely thin. I am convinced it wasn't necessary, but with so little extra work, I still ensured the plaster would adhere better and the wall would definitely open up.
Then pre-wet, regular C-mortar by hand from Weber and silicate paint from Caparol.
