I live in a condominium, brick building. There are some settlement cracks in the building, which became evident when I skim-coated the walls and the cracks clearly appeared (there was previously 50-layer wallpaper). Now I've scraped off what I filled on the wall and chipped away the settlement cracks to fill them with new mortar. But despite this, it still cracks. Can I seal it when I prime the walls? Or what is recommended?