Trim and door painting, where you can see the skill

What is trim and door painting?

Trim and door painting covers baseboards, casings, crown, window trim, interior doors and often the front door. It is finish work rather than coverage work - the surfaces are small, at eye level and under side light, so preparation and application quality are directly visible. It is also usually the slowest part of an interior job per square foot, which is why it is the item most often quietly excluded from a whole-house quote.

Signs you need trim and door painting

• Trim has yellowed while the walls around it have been repainted white
• Baseboards are chipped, scuffed or marked along their whole length
• Doors show hand marks and grime around the handles that cleaning no longer lifts
• Caulk lines between trim and wall have split open
• A colour change on the walls has left the existing trim colour looking wrong
• Previous paint has sagged, run or dried with visible brush marks
• The front door has faded, chalked or blistered on its sun-facing side

Seeing something not on this list? Browse painting problems by symptom →

How trim and door painting actually works

1. 1

   Identifying what is already on the trim

   Older trim in many houses carries oil-based paint. Modern water-based products do not bond reliably to a cured oil surface without preparation, and this is the most common cause of trim paint peeling off in sheets a year later.

   Watch forA crew that does not test or ask. There are simple field checks for an oil-based finish. If nobody establishes it, the adhesion problem is being left to chance on the surface where failure is most visible.

2. 2

   Hardware and fittings removed, not masked

   Door handles, hinges where practical, strike plates and switch plates come off. Painting around hardware leaves a visible ridge and gets paint on the metal.

   Watch forHandles taped rather than removed. It is faster and it is the clearest tell that the rest of the job is being done to a schedule rather than a standard.

3. 3

   Cleaning and de-glossing

   Trim collects grease, hand oils and dust. It is washed, then sanded or de-glossed so the new coat has a mechanical key, particularly on any high-sheen existing finish.

   Watch forPainting straight over glossy trim. The new coat will look fine and will chip off with a fingernail once cured.

4. 4

   Filling, sanding and caulking

   Dents, nail holes and split joints are filled and sanded flush. The gap between trim and wall is caulked to a clean, tooled line - which is what makes the finished trim look sharp rather than approximate.

   Watch forFiller left proud or sanded roughly. On trim it catches light from the side and will be visible from across the room forever.

5. 5

   Priming where required

   Bare wood, filled repairs, knots, and any surface being converted from oil-based to water-based gets a bonding or blocking primer. Knots in particular bleed through white paint without a blocker.

   Watch forKnots painted directly. They bleed brown through the finish, sometimes after months, and the only fix is going back and priming properly.

6. 6

   Application - brush, spray, or both

   Brushing gives control in place and needs a product with enough open time to level out. Spraying gives a glass-smooth finish and is preferred on doors, which are often taken off and sprayed flat.

   Watch forSpraying trim in situ with inadequate masking. Trim spray in a finished room needs extensive containment, and overspray settles on floors, glass and furniture well beyond where you expect.

7. 7

   Second coat and levelling

   Trim almost always needs two coats. Between them, a light sand knocks down raised grain and dust nibs, which is the difference between a smooth finish and a slightly gritty one.

   Watch forNo sanding between coats on doors. It takes minutes and it is the single largest contributor to how a painted door feels under the hand.

8. 8

   Rehanging, refitting and cure

   Hardware goes back and doors are rehung once the paint has hardened enough not to stick in the frame. Paint stays soft for longer than it stays wet.

   Watch forDoors closed before the paint has cured. They stick to the stops and pull the finish off when opened, on the most visible edge of the door.

What does trim and door painting cost?

Trim and doors are usually priced by linear foot and per door rather than by area, because labour per square foot is far higher than on walls. Panelled doors, extensive mouldings and converting an old oil-based finish all push it up. See the Cost Guide.

See the full trim and door painting cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →