How should you paint cement/concrete blocks?

blocks make up a large wall





exteriorHow should you paint cement/concrete blocks?
First, pressure blast it to clean off the surface (or at least hit it with a strong stream from a hose). Let this dry completely (a day or two, depending on temperature and humidity). Next, apply a coat or two of primer for masonry surfaces. Finally, apply a color coat of masonry paint. If you use a roller (as opposed to a sprayer), you might need to use a brush to get the mortar lines between the blocks. And, use a roller with at least a 3/4-inch nap for textured surfaces.How should you paint cement/concrete blocks?
brush them off with a stiff brush then apply a fungicide if they have been affected by mould. A coat of stabilizer and then two coats of masonry paint.


Job done
Remove loose efflorescence, dirt etc. by brushing. Powerwashing works too, but you'll have downtime to let it dry. Use a latex block filler and any exterior latex paint topcoat. If it's a pretty good sized wall, you might want to buy a power painter like a Wagner. Rolling can work, but you'll to get into the mortar joints and imperfections with a brush; unless it's a pretty smooth surface you'll do better in the long run with just brushing the paint on. By the way, masonry will hold paint for a long, long time.