When making the decision to paint a basement floor or foundation walls it’s very important to use a product that bonds and cures properly with masonry or concrete surfaces. These products can be applied directly to the floor or foundation surface with the correct preparation and without primer. Preparation can vary depending on the condition of the surface. If it’s newer masonry or concrete a simple light sanding and cleaning with lukewarm water will work. If the surface is showing efflorescence, dirt, oil spills or other substances that stained the surface it should be power sanded, scrubbed with either diluted phosphoric or muriatic acid and an immediate follow up wash with lukewarm water to make sure all of the acid cleaner has been removed. If the surface has prior paint that is chipping or flaking the entire surface needs to be scraped, power grinded, washed with either of the above acids followed up with lukewarm water to remove the acid cleaner. Make sure the cleaned surface is dried before applying the paint or epoxy.