HOW TO PAINT TRIM & BASEBOARDS

Prep is 70% of a professional-looking trim paint job. Skip it and you'll see every bump, crack, and brush stroke through the finish coat. Pros spend more time prepping trim than actually painting it.

Sand the existing finish

Use 220-grit sandpaper to lightly scuff all surfaces. You're not stripping paint — you're creating microscopic scratches (called “tooth”) for the new coat to grip. Sand in the direction of the wood grain on flat trim. For profiled molding, wrap sandpaper around a foam block or use a sanding sponge to follow the contours.

Fill & caulk

1. Nail holes and dents: Press wood filler into each hole with a putty knife. Overfill slightly — filler shrinks as it dries. Sand smooth after 30 minutes.
2. Gaps between trim and wall: Run a bead of paintable caulk along the seam, then smooth with a wet finger. This eliminates shadow lines that make trim look cheap. Let caulk cure 2 hours before painting.
3. Peeling or flaking areas: Scrape loose paint with a 5-in-1 tool, feather the edges with sandpaper. If bare wood is exposed, spot-prime those areas. See our peeling paint repair guide for stubborn cases.

Clean & tape

Wipe all trim with a tack cloth to remove sanding dust. Then apply painter's tape along the wall edge above baseboards, around window glass, and along walls adjacent to door frames. Press tape edges firmly with a putty knife — loose tape lets paint seep underneath, creating ragged lines.

You don't always need primer on trim. If the existing paint is in good shape and you're staying in the same color family, sanding alone gives enough adhesion. But certain situations absolutely require it.

Apply primer with the same cutting-in technique you'd use for finish paint. One coat is enough. Let it dry completely (check the can — usually 1-2 hours for latex, 4+ for oil-based), then lightly sand with 220-grit to knock down any brush texture before your first color coat.

Trim painting is 100% brushwork — no rollers. An angled sash brush is non-negotiable. The angled tip lets you cut clean lines against walls, floors, and glass. Flat brushes can't reach into corners or follow profiles.

Size guide by trim type

Baseboards are the most scuffed, dirtiest trim in any room. They take shoe kicks, vacuum bumps, and pet scratches daily. A semi-gloss or gloss finish is essential here — semi-gloss vs. gloss both work, but semi-gloss hides imperfections slightly better.

The three-pass method

1. Top edge first. Use the angled tip of your brush to cut a clean line where the baseboard meets the wall. Keep the long bristle edge against the wall. Work in 3-4 foot sections.
2. Face of the baseboard. Load the brush and apply in long, horizontal strokes from one end to the other. Maintain a wet edge — don't stop mid-board and come back later.
3. Bottom edge. Angle the brush down where the baseboard meets the floor. If there's shoe molding, paint it at the same time.

Window trim has the most exposed edges of any trim type. It frames natural light, so every imperfection shows. The key challenge is keeping paint off the glass while getting full coverage into the corner where the casing meets the window frame.

Order of operations

1. Sash and muntins first (if operable windows). Use a 1" or 1.5" angled brush. Let a tiny bead of paint overlap onto the glass — about 1/16" — this creates a seal that prevents moisture from rotting the wood.
2. Jamb (inner frame). Paint the flat surfaces inside the window opening. Use a 2" brush with light, even strokes to avoid drips on vertical surfaces.
3. Casing (outer frame). Paint the wide trim surrounding the window. Work top to bottom: header, then sides, then the sill and apron. The sill is horizontal and prone to drips, so apply thin coats.

After the paint dries, score the paint-to-glass edge with a razor blade at 45 degrees. This creates a crisp line and removes any accidental drips on the glass. A single-edge razor blade holder costs $3 and makes this effortless.

“Let paint overlap onto glass by 1/16 inch. The seal prevents moisture rot at the joint — the razor cleans it up after.”

Door frames are simpler than window trim but have one tricky detail: the hinge side is partially hidden when the door is open. Plan to paint with the door open at about 45 degrees so you can reach both sides of the jamb. If you're also painting the door itself, do the frame first and let it dry before removing the door or taping the hinges.

Parts of a door frame

Hardware tips

• Hinges: Remove the hinge pins and slide out the door, or tape hinges carefully. Never paint over hinges — paint in the pin channel causes sticking and squeaking.
• Strike plate: Remove it (two screws) or tape it. Painted strike plates prevent the latch from engaging.
• Door stop: The thin strip that the door rests against when closed. Paint it, but use very thin coats to avoid buildup that prevents the door from closing flush.

Two coats is the minimum for trim. Semi-gloss and gloss paints are semi-transparent on the first coat — you'll see brush strokes, thin spots, and the old color showing through. The second coat builds opacity, evens out the sheen, and creates the durable film that makes trim paint washable.

Between coats

Removing tape for clean lines

Pull tape while the final coat is still slightly tacky — about 30-60 minutes after application. Pull at a 45-degree angle, slowly and steadily away from the painted edge. If the paint has fully dried and bonded to the tape, score the tape line with a utility knife before pulling to prevent tearing.