[header] How to paint masonry walls [title] Remove any flaked or peeling paint from the masonry. [step] If the wall has already been painted, you need to remove any old paint that is loose, peeling, or flaking away. On an exterior wall, this is most efficiently done with a sandblaster. 
In areas where a sandblaster would be too messy and cumbersome, loose paint can be removed with a stiff wire brush and a paint scraper. [substeps] Failing to remove loose and peeling paint can result in the paint flakes mixing in with your fresh coat of paint and marring the finish.