The short answer
Let primed doors acclimatize for at least 72 hours indoors, scuff sand the primer with 180 to 220 grit, then apply at least two coats of good paint, sanding lightly between coats. Paint all six sides, including the top and bottom edges and the hardware cut-outs. Factory primer is not a sealer.
Before you paint
- Acclimatize. Store doors and trim flat and indoors in the rooms where they’ll go, with the HVAC running, for at least 72 hours. Longer if the site is very dry or humid.
- Seal stored doors. If doors will sit on site for more than a week before finishing, seal all six sides first. Primer alone lets moisture in.
- Check for bow. Don’t paint a door that has bowed in storage. Paint locks the bow in.
Painting doors
| Step | What to do |
|---|---|
| Scuff | Lightly sand the primer with a 180 to 220 grit sponge so the paint has something to grip |
| Clean | Remove the dust and fill any nail holes |
| Lay it flat | Paint the door horizontal, so the paint levels and doesn’t run |
| Coat 1 | A good quality interior paint, faces and all four edges |
| Sand | A light sand between coats |
| Coat 2 | The finish coat. A third if the colour or sheen needs it |
| Top and bottom | Seal both end edges and every hinge and lock cut-out |
The bottom edge is easy to miss once a door is hung. An unsealed bottom draws moisture from floor cleaning and humid bathrooms, and the door can swell or warp.
Painting trim
- Fill and caulk first. Fill nail holes, caulk the joint between casing and wall, then sand smooth.
- Seal cut ends. Mitred and coped ends are bare wood or MDF. Prime them before the finish coats, especially on baseboard near bathrooms and entries.
- Same white everywhere. Our doors and trim come in the same factory primer, so one finish colour covers both.
Why it matters for the warranty
Our doors and trim are supplied primed, to be stored flat, indoors and dry, and painted on all six edges after installation. Damage from improper storage, installation or finishing isn’t a defect under our terms. The steps above are what keeps a door flat and the paint on.
Sources
- Interior MDF door care, handling and finishing instructions, TruStile (PDF)
- Inspection, damage and defects, Premier Building Products terms
Code requirements change and local rules vary. Confirm sizes and clearances with your designer and building department before ordering. We supply doors, trim and hardware; we’re not a code consultant.
