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Get a natural roller with a thick nap. Fill your paint tray with your paint and run the roller back and forth in the tray to load it. Apply paint to the larger surfaces of your wall using vertical back-and-forth strokes. Cover each area 3-4 times with your roller as you paint to fill in the pores. Leave the 3–6 in (7.6–15.2 cm) around the top, bottom, and sides of the walls unpainted to avoid messes accidentally rolling the wrong surface. You can use paving paint or porch-and-floor enamel for smoother concrete if you’d prefer. Waterproof masonry paint will work on either cinderblock or concrete walls. After waiting at least 2 days for the paint to dry, grab another sheet of sandpaper or a sanding brick with a grit of 40-80. Sand your primed walls using circular strokes to remove the upper layer of the paint and make the surfaces paintable. If you don’t sand your primed walls, the paint will peel, crack, or fail to hold up in cold or hot temperatures. Once you’ve sanded your finished walls, fill a clean paint tray with your paint. Opt for semi-gloss to protect your basement walls from moisture or water. Fill your roller in the paint tray and roll the larger sections of your walls, leaving the 3–6 in (7.6–15.2 cm) around the edges unpainted. Work slowly and apply even pressure with your roller to get a beautiful base coat.  You can use matte or flat paint if you’ve never had any issues with water in your basement. Semi-gloss paint will be easier to clean and will do a better job of protecting your walls though. Use standard paint on stucco or plaster walls as well. Whether it’s concrete, cinderblock, or finished drywall, you will finish the trim the same way. Get a 2–3.5 in (5.1–8.9 cm) angled brush with natural bristles. Load your brush and use the rim of the paint tray to scrape excess paint off of the brush. Carefully paint the trim around the edges of each wall, angling the tip of your brush towards the exterior edge as you paint around the ceiling, adjacent walls, or floor. Use even back-and-forth strokes to paint the trim. You can use a nylon brush to paint finished walls if you prefer. Let your first coat dry for 2-3 days. Then, apply a second coat to your basement walls using the same method that you used the first time. Roll the center of each wall first and then paint the trim using the same brand and color of paint. When you’re done painting, clean up, vacuum any dust off of the floor to keep it from kicking up into the wet paint. Wait at least 3 days before touching your walls or putting any furniture back.
Roll your cement walls with waterproof masonry paint and a thick-nap roller. Sand finished walls a second time before painting. Use a roller to paint finished walls with a semi-gloss paint. Paint your trim with an angled brush. Apply a second coat to finish painting your walls. Clean up and wait 48-72 hours before touching your wall.