Oil enamel under latex is a bonding problem
Oil-based (alkyd) paint cures to a hard, slick film. Water-based latex sits on top unless you dull the gloss and use a bonding primer. Skipping either step is why DIY kitchen and trim paint peels in sheets.
Confirm you actually have oil with the alcohol wipe test before you buy primer.
Prep steps that make latex stick
Full room sequence: prep walls → choose primer → paint step by step.
- Clean grease and soap film (TSP substitute) — especially kitchens and bathrooms
- Sand to dull sheen (120–150 grit); you do not need to strip to bare wall
- Vacuum and wipe dust with a damp microfiber cloth
- Caulk trim gaps; spot-fill dents; sand patches smooth
- Apply bonding primer labeled for glossy / oil surfaces — full coat, not spotty
- Topcoat with quality latex after the primer recoat window
Trim and doors vs wall fields
Trim is often oil while walls are latex. Paint walls and trim as separate systems: bond-prime oil trim, then finish with latex enamel or acrylic trim paint for durability.
Estimate wall gallons separately from trim — trim uses less area but more brush work. Wall totals still come from the how much paint calculator.
Mistakes that cause peeling
If paint is already peeling, scrape to a firm edge, sand, prime bare spots with bonding primer, then finish. See also how to fix peeling paint.
- Latex straight over glossy oil with no sanding or bonding primer
- Painting over chalky or peeling oil without scraping loose film first
- Recoating primer or finish while still soft — see recoat timing
- Heavy grease left on kitchen walls under primer