Interior · 6 min read
Painting interior trim and doors: what makes trim look professional
Crisp trim comes down to prep, the right enamel and patient brushwork. Here’s what separates trim that looks professional from trim that looks rushed.
Key takeaways
- Professional-looking trim starts with prep: caulked joints, filled and sanded nail holes, and light sanding between coats.
- Water-based trim enamels, such as waterborne alkyds and urethane-modified acrylics, generally resist the yellowing that white oil-based paint shows over time.
- Use one trim color and sheen throughout the house, and paint panel doors in a set order so the final strokes follow the grain.
- Stained or varnished trim can be painted after cleaning, deglossing and a stain-blocking primer, but whether to paint original wood is a judgment call.
Sherwin-Williams colors in this guide
Professional-looking trim comes from prep and patience more than talent: tight caulked joints, filled and sanded nail holes, light sanding between coats, a hard-wearing trim enamel in satin or semi-gloss, and thin coats brushed in long strokes. Doors follow a set order, and painted surfaces need time to harden before they close.
Trim gets judged up close, at eye level and under raking window light. Here’s what makes it look right, from the first bead of caulk to the last door. For whole rooms, see our interior painting page.
How should trim be prepped before painting?
Most of what makes trim look professional happens before the can opens. Our guide to why prep is the paint job covers the whole house; on trim, these steps matter most:
- Clean. Hands leave oils on door edges, casings and rails. Wash with a mild degreasing cleaner and rinse.
- Dull the old finish. Scuff-sand glossy paint or wipe on a liquid deglosser so the new coat can grip.
- Fill nail holes. Press in wood filler or spackle slightly proud, sand it flush when dry, and spot-prime so patches don’t show as dull spots.
- Caulk the gaps. Run thin beads of paintable caulk where casings and baseboards meet the wall and in seams between trim pieces, then smooth them with a damp finger or rag. Caulk is for joints; filler is for holes.
- Sand between coats. A light pass with fine sandpaper or a sanding sponge knocks down dust nibs and raised grain. Wipe the dust away before recoating.
Old trim often carries decades of paint, and in homes built before 1978 some of it may contain lead. The EPA’s Renovation, Repair and Painting (RRP) rule requires certified firms and lead-safe work practices for paid work that disturbs more than 6 square feet of painted surface per room inside; the EPA’s RRP page has the details.
What kind of paint is best for trim and doors?
Trim takes knocks, scuffs and hands, so it gets a harder paint than walls. Most paint makers, Sherwin-Williams among them, sell several kinds of trim enamel:
- Waterborne alkyds clean up with water but are formulated to level out and dry hard, with some of the feel of oil paint.
- Urethane-modified acrylic enamels add urethane to a water-based paint for a tougher, more block-resistant film.
- Oil-based enamels level beautifully and dry hard, but they dry slowly, need solvent cleanup and smell strongly. White and pale oil paints also tend to yellow with age, often most where daylight never reaches, such as behind doors and inside closets.
The water-based options generally resist yellowing better than oil, one reason many painters now use them on white trim. Products vary in leveling, hardness and dry time, so read the product data sheet, not just the front of the can. And if the existing trim is oil-based, water-based paint needs a bonding primer underneath.
Should trim be semi-gloss or satin?
Semi-gloss is the traditional trim sheen: durable, easy to wipe clean, and a crisp contrast with flatter walls. Its shine also spotlights every dent and patch, so on old, heavily painted trim, satin can look smoother while still cleaning reasonably well. Our paint sheen guide covers the full range.
Whichever you choose, use one trim color and one sheen throughout the house. Trim runs through doorways and halls from room to room, and consistent trim ties the rooms together. It also means one can handles every touch-up, as our guide to touching up paint explains.
Extra White SW 7006, a bright, crisp white that leans slightly cool, is a favorite for trim. Pure White SW 7005 is softer, with a touch of warmth, and Alabaster SW 7008, a warm, creamy off-white, can suit an older home with warm walls. Screens and chips mislead, and whites shift with the light and the wall color beside them, so test samples on your own trim.
How do you brush trim without leaving brush marks?
Start with a good angled sash brush sized to the trim: synthetic bristles for water-based paint, natural bristles for oil. Dip the lower third or so of the bristles and tap off the excess.
- Lay it on, then lay it off. Apply paint to a short section, then finish with long, light strokes along the length of the board.
- Keep a wet edge. Work from fresh paint into fresh paint. Water-based enamels set quickly, especially in a warm, dry room.
- Don’t overwork it. Most brush marks come from going back over paint that has started to set. Catch a missed spot on the next coat.
- Use thin coats. Two thin coats beat one heavy one, which can sag and drip at corners and edges.
Where trim meets the wall, cut a straight line with the tip of the brush. Tape helps, but it’s no substitute for a steady hand.
What order should you paint a panel door in?
A set order lets each step overlap the edges of the one before, so the final strokes on each part run with its grain. For a typical six-panel door:
- Hardware off, or masked. Many painters take the door down and lay it flat on sawhorses, where paint is less likely to sag.
- Panels: the molded edges around each panel first, then the flat panel faces.
- Center stiles: the vertical pieces between panels, brushed up and down.
- Rails: the horizontal boards across the top, middle and bottom, brushed side to side.
- Outer stiles: the long vertical boards on each side, brushed top to bottom.
- Edges: the latch and hinge edges. Some door makers also call for sealing the top and bottom edges, so check.
A flat, flush door is simpler: roll it with a small foam or microfiber roller, then smooth it with long, light brush strokes while the paint is still wet.
How long before painted doors and windows can close?
Longer than you’d think. Paint that feels dry can still be soft underneath, and when two newly painted surfaces press together, such as a door against its stop or a sash against its frame, they can stick. Painters call it blocking, and pulling the surfaces apart can tear the paint.
Many trim enamels are formulated to resist blocking, but how well varies by product, and all of them need time. Follow the label’s recoat times, leave doors open as long as you practically can, and expect slower drying on humid Michigan summer days or in a cool, closed-up room. Our article on dry time versus cure time explains why paint keeps hardening long after it feels dry.
Can you paint over stained or varnished trim?
Yes, with the right prep. Paint won’t hold on slick varnish or grime, and some woods fight back:
- Clean off furniture polish, wax and hand oils, then rinse.
- Degloss by scuff-sanding or with a liquid deglosser. The goal is dulling the shine, not stripping it.
- Prime with a bonding, stain-blocking primer. Tannins in woods such as oak and mahogany can bleed yellow-brown stains through water-based paint, and pine knots can bleed resin. Shellac-based and oil-based primers are common choices; check the label for what each one blocks and bonds to.
- Expect some texture. Open-grained oak can show its grain through paint unless the grain is filled first.
Should you paint original wood trim in an older home?
It’s one of the most debated questions in older houses, and there’s no single right answer. Many early-20th-century homes in Grosse Pointe and across Metro Detroit were built with stained wood trim, especially Craftsman and Tudor Revival houses, while Colonial Revival and Georgian interiors were often painted from the start.
The case for painting: it brightens dark rooms, unifies trim that has been patched or mismatched over the years, and suits lighter decor. The case for keeping the wood: it’s part of the house’s original character, and paint is hard to undo. Stripping painted trim back to clean wood is slow, messy work, and in a pre-1978 house it means disturbing paint that may contain lead.
Some owners split the difference, keeping wood in the principal rooms and painting it in kitchens, baths and bedrooms. Worn but sound wood can also be cleaned and its finish refreshed instead. Our guides to painting older Grosse Pointe homes and painting plaster walls cover the rest of the room.
Questions
What sheen is best for interior trim?
Semi-gloss is the traditional choice because it’s durable, easy to clean and contrasts with flatter walls. Satin is softer and hides dents and old patches better, which can suit heavily painted trim in older homes. Whichever you pick, use the same sheen on trim throughout the house.
Do you need to sand between coats of trim paint?
A light sanding between coats with fine sandpaper or a sanding sponge gives the smoothest finish, because it knocks down dust nibs and raised grain. Wipe the dust off before recoating. It’s one of the simplest differences between trim that looks rushed and trim that looks professional.
Why does white trim turn yellow?
Oil-based paints tend to yellow as they age, and the effect is often worst where there’s little daylight, such as behind doors and in closets. Water-based trim enamels generally resist yellowing better. Yellowed oil-based trim can be repainted with water-based paint after cleaning, deglossing and a bonding primer.