How to Paint Trim and Skirting Boards Cleanly

Photo by Jeremy Boley on Unsplash (https://unsplash.com/photos/1633549435428-b06aa4b1a977)

By Jen — IDIY’s painter and decorator.

Painting trim and skirting boards is the bit that separates a “we painted the lounge” job from one that looks bought-in. The walls are the easy part. The trim — skirtings, architraves, door frames, window sills — is where messy paint lines, drips, and dust-bumps show themselves at every glance. The technique below is what we use across Melbourne renovations every week, and it’s slower than you’d hope but the result lasts and looks professional.

What you’ll need

2L of premium gloss or semi-gloss enamel (Dulux Aquanamel, Taubmans Tradex Trim — water-based enamel is what we use; oil-based gives a harder finish but takes a day to dry between coats)
A 50mm angled cutting-in brush (Purdy is the benchmark — a $35 brush will outlast ten cheap ones)
A 25mm sash brush for tight spots
Frog Tape multi-surface (yellow)
120 and 240 grit sandpaper
Sugar soap or methylated spirits
Wood filler for nail holes and dents
A drop sheet (canvas, not plastic)

Step 1: Wash trim with sugar soap or metho

Trim collects more skin oils, kitchen grease, and dust than walls do. Wipe every linear metre of skirting and architrave with sugar soap and a cloth, or metho on a microfibre. Water-based enamel doesn’t bond to grime — a clean surface is the difference between paint that lasts ten years and paint that flakes in two.

Step 2: Fill nail holes and dents

Wood filler in any nail holes, gouges, dings. Press it in firmly, level off with a putty knife. Let dry per the can (usually 30 minutes). Sand smooth with 240-grit.

Step 3: Sand all trim with 240-grit

Light hand-sanding all over, even on previously-painted trim. This dulls the existing paint so the new coat bonds, and it removes any high spots from filler. You’re not stripping paint — you’re scuffing it. Sandpaper folded into quarters, two minutes per metre.

Step 4: Vacuum and tack-cloth the trim

Vacuum the dust off, then wipe with a slightly damp microfibre. Any dust left on the surface ends up in your paint as visible bumps. Especially important for gloss enamel, which photographs every flaw.

Step 5: Tape — but tape onto the wall, not onto the floor

Frog Tape along the wall side of skirting, pressed firmly with a putty knife. The paint goes over the tape edge a couple of millimetres — that’s intentional, the tape catches it. Don’t tape the floor side — you’ll cut the line by hand or accept the floor catching a tiny line of enamel that wipes off.

Step 6: Cut in along the wall edge first

Load the angled brush properly — one-third of bristle into paint, tap (not wipe) on the can edge. Long, smooth, confident strokes along the top edge of the skirting where it meets the wall. Slow down at corners. Don’t dab — drag.

Step 7: Fill in the body of the trim with the same brush

For skirtings, two horizontal passes top and bottom, then a horizontal pass along the middle. Always finish in the long direction (with the grain of the trim). For architraves, do the long sides first, then the short top piece.

Step 8: Pull tape while paint is just-tacky, not dry

Same rule as wall paint — tape pulled while paint is dry rips paint off with it; tape pulled while paint is wet smears. Just-tacky is the sweet spot. Pull at a 45° angle, slowly, away from the freshly painted surface.

Step 9: Wait the recoat time, then second coat

Read the can — water-based enamels are usually 2 hours; oil-based are overnight. Patience here matters more than on walls because trim is high-glare and any pulling-up of the first coat by a too-soon second coat shows forever. Same process: cut in, fill, smooth.

Step 10: Door edges last, with the door open

Doors get painted with the door open and the hinges visible. Three sides of the door (top, latch side, hinge side) get a thin coat of enamel — bottom and the inside of the hinge edge can stay un-touched if they’re already covered. Don’t shut the door until the paint is fully dry (overnight) — wet enamel sticks to itself.

The Jen rule

Trim is 20% of the area and 80% of the visual quality. If you’ve got time for one coat on walls and two coats on trim, do that — the trim is what people notice. Two thin coats of trim enamel beats one heavy coat every single time.

Doing something tricky — distressed trim, period mouldings, painting over varnish? Send us your project.