How to Paint Cement Blocks
Unpainted cement blocks can have a dingy, industrial appearance. Painting cement, concrete or cinder block, whether it's your home's foundation, basement walls or simply makeshift shelving supports, requires nothing more than basic painting tools and water-based paint. Clean interior concrete blocks need little preparation besides a quick dusting, although exterior walls need to be cleaned and primed for a paint job that will look good for many years. Most paint jobs fail because of inadequate preparation; cement block holds paint very well as long as you thoroughly clean the surface and use high-quality primer and paint.
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Things You'll Need
- Wire brush
- Power washer
- Detergent
- Acidic masonry cleaner
- Caulk
- Mortar
- Putty knife
- Screwdriver
- Masonry primer
- Roller
- Paint brush
- Airless sprayer
- Paint
Instructions
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Clean the cement block. If it's relatively new and clean, simply dust it off with a brush. Clean dirty cement block with detergent and a wire brush, or use a power washer on large expanses of exterior block.
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Remove efflorescence by scrubbing with detergent and rinsing thoroughly. Efflorescence appears as a white, powdery coating on the surface of the block. If it's crystallized and hard, use an acid wash formulated to dissolve and remove it.
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Repair cracks with caulking or mortar. Use a stiff putty knife or screwdriver to widen hairline cracks first.
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Prime the cement block with water-based masonry primer. Use a brush and long-nap roller for smaller areas, or an airless sprayer for large areas. Allow it to dry for about eight hours. You may skip this step if the cement blocks are inside in a dry area and not part of your home's structure, such as supporting bookshelves.
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Apply two coats of flat, satin or semi-gloss 100 percent acrylic paint. The higher the gloss, the easier the block will be to clean, but a higher gloss finish will also accentuate surface irregularities. Satin finish paint is a good compromise between wash-ability and appearance.
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Tips & Warnings
Use block fill primer or elastomeric paint to fill spaces or extensive surface cracks in the concrete surface and to provide a smoother-looking appearance.
Very rough or split-face block will require twice as much primer and paint as smooth cement block.
Wear eye protection and gloves when using cleaners to remove efflorescence; they are acidic and will burn or irritate skin and mucous membranes.
References
Resources
- Photo Credit block wall image by Irina Kodentseva from Fotolia.com
