You want the surface to be as clean and bare as possible for the best coating of paint later on.
Cleaning concrete prior to painting.
Acid etching is the process of applying hydrochloric muriatic or buffered phosphoric acid to a slab then rinsing it off with water.
Existing paint needs to be scraped and sanded.
For many years it was a standard method of concrete preparation used by nearly all industrial commercial and institutional floor coating installers depending on the floor size and system to be installed.
To make the best result in cleaning the concrete wall that is not already painted you also can add another bucket that you should fill with warm water.
Allow the concrete surface to dry.
Opening up a tight surface.
Remove dirt and grease with trisodium phosphate 6 30 per quart concentrate or choose a more earth friendly.
Next you can use a stiff or scrub brush with water that you already filled with soap to scrub the walls.
Hydrogen peroxide or ammonia also work well too.
Use a pressure washer to finish off remaining roots and dirt.
Pour dry dishwasher detergent or a concrete cleaning agent on the stain.
Let the detergent sit for 45 minutes then pour boiling water on the area and vigorously scrub the stained section with the broom.
The bad news for the fastidious homeowner is that.
Prepare to mop the concrete with a trisodium phosphate solution tsp.
For stubborn stains use muriatic acid in combination with your pressure washer set to at least 1200 psi.
Using a wet vacuum will dry the areas quickly without wetting the rest of the concrete.
Scrape any areas with loose or flaking paint and lightly sand using fine 120 grit sandpaper.
Yank off vines and moss growing on the foundation.
Your supplies are likely to be a bucket scrub brush and detergent.
Prime and paint priming before you paint concrete floors helps ensure that your new look will stick.
If oil happens to migrate to the surface darkening it before you can coat it it can be cleaned again dried and painted as soon as possible to allow the paint to dry before the stain reappears another time.
Yank off any vines moss or other plant life covering the concrete.
Remove efflorescence a white powder that.
Clean the concrete 1.