Getting new paint to stick to old glossy trim

Quick answer

Latex paint applied directly over old oil-based enamel often peels. The trim needs cleaning, light scuffing and a bonding primer first. Homes built before 1978 may have lead in old paint layers, so we avoid dry sanding.

Trim, doors and window casings in older San Gabriel homes were typically finished in oil-based enamel. It wore well. The problem comes when someone paints latex over it without prep, and it peels off in sheets.

How to tell

Prep steps

• Clean grease and grime with a degreaser.
• Scuff the glossy surface lightly.
• Wipe off dust.
• Prime with a bonding primer.
• Paint with a quality enamel.

Lead caution

Peeling paint repair

If latex is already peeling, we scrape loose paint, feather edges, prime and repaint.

Choosing sheen

Semi-gloss or satin enamel suits trim and doors, and cleans easily.

Where oil-based paint hides

In older San Gabriel homes, oil-based enamel is common on window sashes and casings, door frames, baseboards, built-in cabinets and the doors themselves. Kitchens and bathrooms often have oil paint on walls too, because it was considered washable.

Test each surface separately; previous owners may have repainted some with latex and left others.

Why latex peels off oil

Oil-based enamel dries hard and glossy. Latex paint is flexible and does not bite into that hard surface. Without primer, it sits on top like a skin, and the first time tape or a bumped piece of furniture catches it, it peels.

Choosing primer

Bonding primers are made to grip glossy surfaces. Oil-based primers also work well over old oil paint. Once primed, you can finish with a water-based enamel that levels well and stays hard.

Lead-safe practices

For homes built before 1978, we protect floors, contain dust, use wet scraping and sanding methods, and clean up with a HEPA vacuum and wet wipes. Lead testing is a good idea if a project will disturb a lot of old paint.

Testing for oil paint

Trim, doors and cabinets in older San Gabriel homes were commonly painted with oil-based enamel. Latex paint does not bond well to glossy oil paint and can peel off in sheets. To test, rub a small area with a cotton ball soaked in denatured alcohol.

If paint softens and comes off on the cotton, it is latex. If nothing happens, it is likely oil.

Lead paint

Paint applied before 1978 may contain lead. Test before sanding. Lead-safe work practices include wet sanding, plastic sheeting, HEPA vacuums, and careful cleanup. Contractors working for pay in pre-1978 homes must follow the EPA lead rule.

Preparing the surface

Our steps:

• Clean with a degreaser to remove grease and grime
• Rinse and let dry
• Scuff sand lightly to dull the gloss
• Vacuum and wipe off dust
• Prime with a bonding primer made for glossy surfaces
• Paint with your topcoat

Bonding primers grip glossy paint. Oil-based primers also work and are good at blocking stains.

Choosing paint

Water-based alkyd enamels flow out smoothly, dry hard, and clean up with water. They are a good choice for trim and cabinets. Traditional oil enamels are harder to find and have strong fumes. Acrylic latex trim paints are durable but can stay soft longer.

Brushing and rolling

Use a quality angled brush for trim, and a fine foam or microfiber roller for flat surfaces. Thin coats dry better and level more evenly. Allow full drying time between coats.

Doors and windows

Paint buildup makes doors and windows stick. Remove excess paint at edges before painting. Do not paint window channels or weatherstripping.

Drying and curing

Paint feels dry before it fully cures. Avoid closing doors or using cabinets heavily until the paint has cured, often several days.

Repairs before painting

Fill holes and cracks with wood filler or caulk. Sand smooth. See sagging cabinet doors in older kitchens and sticky wood windows.

Common failures

Peeling in strips means paint was put over glossy oil paint without proper primer. Alligatoring, a crackled surface, happens with too many layers or incompatible paints. Wrinkling comes from paint applied too thick.

Tackiness comes from latex not curing properly over oil. In each case, the failed paint has to be scraped back to sound paint, sanded smooth, primed and repainted. Catching a problem early on a small test area saves a whole room.

Test first

Paint a small, out-of-sight area first. After a few days, press tape firmly on it and pull it off. If paint lifts, the prep or primer is wrong.

Hardware

Remove hinges, knobs and plates before painting rather than painting around them.

Ventilation and cleanup

Open windows and run fans while priming and painting. Oil-based primers have strong fumes; wear a respirator rated for organic vapors when using them indoors. Water-based alkyds have far less odor.

Clean brushes right away. Dispose of oil-based paint and solvents at a household hazardous waste site, not in the trash or drain.

Most trim jobs look best with two finish coats over primer. Light sanding with fine grit between coats gives a smoother finish.

Let the primer dry for the full time on the can before the topcoat goes on, even if it feels dry sooner.

What our visit involves

We test, prep, prime and paint trim, doors and casings. See drywall, plaster and paint.

Paint prep near Las Tunas Drive leaves time for a long lunch at Newport Seafood.

Want us to handle it?

Call or text (626) 684-3505, Mon–Sat 8:30 AM–7 PM. Send a photo and we will give you an upfront quote.

Call or text (626) 684-3505