How to paint a garage door?
Yes. Steel and aluminium garage doors take exterior paint well, provided you deal with any rust before you start. Use a rust-inhibitive metal primer. Prep decides whether the finish is still attached in two years, so it is worth more of your time than the colour choice.
Short version
- Yes.
- Prepare it: wash off dirt and chalk, sand any rust back to sound metal, and prime bare spots with a rust-inhibitive metal primer.
- Prime with a rust-inhibitive metal primer.
- Most common failure: rust bleeding back through within a season, and lap marks from paint drying too fast on a hot panel.
How to prepare the surface
Wash off dirt and chalk, sand any rust back to sound metal, and prime bare spots with a rust-inhibitive metal primer.
Then prime with a rust-inhibitive metal primer. Priming is not optional on this substrate — it is the step that decides whether the finish is still attached in two years.
What to watch out for
Work when the panel is in shade and the surface is not hot. A south-facing metal door in direct sun gets hot enough to flash the paint off before it can level out.
How this job usually fails
Rust bleeding back through within a season, and lap marks from paint drying too fast on a hot panel.
Common mistakes
- Skipping the primer because the existing surface "looks fine" — adhesion is decided by the substrate, not by appearance.
- Recoating on "dry to touch" rather than the recoat time on the product's data sheet.
- Using wall paint on a surface that gets handled or walked on.
- Painting in direct sun or on a hot surface, which stops the film levelling.
Related questions
Sources
- Sherwin-Williams. Product technical data sheets (accessed 2026-08-17).
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