Can I paint over old paint?

Yes, you can paint over old paint in most cases, and it is common practice, but you must prepare surface properly for good adhesion and long lasting finish. If old paint is in good condition, clean, not peeling, cracking, or glossy, you can paint over it after cleaning walls with soap and water, lightly sanding to degloss, especially if old paint is oil based or high gloss, and applying new paint. If old paint is oil based and you want to use latex, you must sand and prime with bonding primer, otherwise latex will peel. If old paint is peeling, chipping, or flaking, you must scrape loose paint, sand edges, fill holes, and prime bare spots, otherwise new paint will peel. If old paint has mold or mildew, clean with mildew solution. If wall is very dark and you are going light, use primer first to block color and reduce coats. If old paint is flat or matte latex in good condition, you can often paint directly with two coats. Always test adhesion by pressing tape. For best results, lightly sand, wipe dust, prime repairs, and use quality paint. So yes, you can paint over old paint if surface is clean, dull, dry, and sound, but never paint over failing, greasy, or glossy paint without prep and primer.