How long cement dry before painting

Cleaning concrete is a vital first step because the porous surface tends to trap dirt, grease, and oil. Yank off vines and moss growing on the foundation. Use a pressure washer to finish off remaining roots and dirt. Remove efflorescence, a white powder that forms on moist concrete.

Water moves easily through porous concrete, so sealing interior walls is necessary to prevent moisture from seeping in, promoting mold growth and that cold, damp basement feel. If the finishing process was recently completed, rainwater may not cause damage as long as it is not worked into the surface and the slab is left untouched. If no darkening of the concrete or condensation is evident after 24 hours, the floor is dry enough to paint.

The floor should be thoroughly cleaned and acid etched prior to application. Efflorescence is a chalky white salt residue that can occur with any product containing cement. As moisture migrates up to the surface of the concrete , it carries along with it calcium salts from within the concrete. When the salts reach the surface, they react with CO2 in the air and form insoluble calcium carbonate. Allow the concrete wall to completely dry after pressure washing. This is very important because if any moisture is left in the wall while it is being sealed, that moisture will be trapped and gradually break down and crack the concrete.

It may take up to 24 hours for the concrete to thoroughly dry. A fresh coat of paint or stain can really spruce up concrete basement or garage walls and floors and bring new life to a worn concrete patio. Concrete paints and stains help to mask surface discoloration and signs of wear and tear and they extend the life of concrete by preventing further damage.

Step 1 - Cleaning and Scrape Allow the concrete surface to dry. Existing paint needs to be scraped and sanded. Scrape any areas with loose or flaking paint , and lightly sand using fine grit sandpaper.

Lightly sand intact areas of paint as well to give them the grit needed to receive new paint. Before applying a water-resistant paint , clean and roughen the surface. Use a trisodium phosphate solution or strong detergent to scrub the floor.

Ordinary latex paint is well-suited for interior concrete walls. Use an eggshell or satin latex paint on concrete walls that aren't exposed to much duress. After it dries, run your hand over the concrete; it should feel like grit sandpaper.

Sweep the area or wipe it down with a dry cloth, depending on the orientation of the surface. Use a paintbrush to apply an initial coat of paving paint or porch-and-floor enamel over the perimeter of the area. Let that first coat of paint dry for at least 16 hours or so.

Putty knife in hand, scrape away any protruding lumps or bumps that appeared after the first coat dried. Apply the second coat of paint in the same way that you applied the first. Before considering the project complete, let the second coat dry for about five days, particularly if the painted surface is a heavily trafficked floor.

After rinsing, let the surface dry completely. In some damp basements this could take up to five days or more. Use a dehumidifier if you have one. If your thermostat has a fan switch, set the fan to run continuously for several days. Circulating the air will allow you to continue your project sooner. A mild etcher improves the bonding ability of paint to old concrete.