Exterior · 7 min read
Painting aluminum siding: what Michigan homeowners should know
Aluminum siding on post-war homes takes paint well, as long as the chalky surface comes off first. Here’s what the job involves and how to make it last.
Key takeaways
- Aluminum siding can be painted successfully, but only after the chalky, oxidized surface is scrubbed off and the siding has dried completely.
- A simple tape test shows whether the old factory finish is sound enough to paint over; anything that lifts must be scraped and primed.
- Bare or corroded metal needs a primer made for aluminum, and a quality 100% acrylic exterior paint is the standard finish.
- Lighter colors and a satin or low-luster sheen are the forgiving choices, since gloss highlights dents and dark colors show fading sooner.
Sherwin-Williams colors in this guide
Yes, aluminum siding can be painted, and a careful job can make faded, chalky siding look crisp again. The paint is the easy part. What decides whether it lasts is prep: washing off the chalky oxidized surface, confirming the old factory finish is still holding tight, and priming any bare metal.
Aluminum siding went up on many post-war homes across Metro Detroit, from Capes and ranches to Colonials, and plenty of it is still on the wall. After decades of sun and Michigan winters, the factory color has usually faded and turned powdery. Painting gives it new color and a new protective film without tearing anything off. Here’s what a sound job involves, whether you do it yourself or make it part of an exterior painting project.
Why does aluminum siding turn chalky?
Aluminum siding left the factory with a baked-on painted finish. Over years of sunlight, the binder in that finish breaks down and releases its pigment as a fine powder. Homeowners often call it oxidation; painters call it chalking. It’s why your hand comes away white, or tinted with the siding’s color, when you brush it along a sunny wall.
That powder is the enemy of new paint. Paint applied over chalk sticks to the chalk, not the siding, and the chalk lets go. The result can be paint that flakes or peels long before its time, often in patches that show the old color underneath.
How do you get the chalk off?
Rinsing alone rarely does it; chalk needs scrubbing. Use a siding cleaner or a TSP substitute, mixed according to its label, and work it in section by section with a soft-bristle brush on a pole. Apply cleaner from the bottom up so it doesn’t streak down dry siding, then rinse from the top down, thoroughly, before it dries. Leftover cleaner can interfere with adhesion just as chalk does.
A pressure washer can help with rinsing, but keep the pressure low and the spray angled downward. Aluminum is thin and dents easily, and a hard spray aimed upward can drive water behind the panels and into the wall. Rinse shrubs and plantings before and after, since some cleaners can harm them.
Then let everything dry: water hides in laps, corners and trim. It’s the same careful prep every exterior needs.
Will the old factory finish hold new paint?
New paint is only as sound as the coating under it, so once the siding is clean and dry, test whether the old finish is holding tight. Press a strip of strong tape, such as duct tape, firmly onto several spots, especially on sunny walls, and pull it off in one quick motion.
If the tape comes away clean, the finish is sound. If it lifts flakes, that area needs to be scraped and sanded back to a firm edge, and any exposed metal primed. Siding that has been painted before deserves extra scrutiny, since an earlier coat applied over chalk may be holding on only loosely.
Homes built before 1978 may contain lead-based paint, on wood trim, windows and porches as well as in any earlier coats on the siding. The EPA’s Renovation, Repair and Painting (RRP) rule requires certified firms and lead-safe work practices for paid work in pre-1978 homes that disturbs more than 6 square feet of painted surface per room inside, or more than 20 square feet outside. The EPA’s RRP program page has the details.
When does aluminum siding need primer?
Not always. When the factory finish is clean, chalk-free and sound, many quality exterior acrylic paints can go directly over it. The label will tell you whether a paint suits aluminum siding and whether it calls for a primer first.
Primer earns its place in three situations:
- Bare metal. Wherever the finish has worn through, been scratched or been sanded off, spot-prime with a primer labeled for aluminum or other nonferrous metal. Many paints don’t grip bare aluminum well without one.
- Corrosion. Exposed aluminum can develop a white, powdery corrosion. Scrub it off with a synthetic abrasive pad, wipe the spot clean, and prime it promptly.
- Stubborn chalk. If a light film remains after thorough washing, some primers and paint conditioners are formulated to bind it. Check the label, and treat them as a backup to cleaning, never a replacement for it.
What kind of paint should you use on aluminum siding?
A quality 100% acrylic exterior paint is the standard choice. Acrylic stays flexible as the metal expands in summer heat and contracts in winter cold, holds its color well in sunlight, and bonds well to clean, sound, properly primed siding. Oil-based paints tend to turn brittle and chalk outdoors, which is why they’ve largely fallen out of use on siding.
We paint with Sherwin-Williams. Whatever brand you choose, read the label to confirm the paint is suited to aluminum siding, and plan on two finish coats in most cases for even color and a durable film.
Conditions matter as much as the can. Siding in direct sun gets far hotter than the air, so paint dries too fast and leaves lap marks; in the evening, metal cools quickly and can collect dew before paint sets.
So follow the shade around the house, stop early enough for the paint to firm up, and check the label’s minimum temperature, which applies to the siding as well as the air. Our guide to timing an exterior paint job in Michigan covers the season.
What about dents and damaged panels?
Paint changes color, not shape. Dents, dings and waves will still be there afterward, and a glossier finish makes them easier to see.
Small dents can sometimes be filled with a filler made for exterior metal, sanded smooth and primed, though a fill can crack if the panel flexes. Torn or badly crushed panels are better replaced, and loose ones refastened, before painting. A replacement in a matching profile can take some searching, but it doesn’t need to match the old color: once the house is painted, it blends in with the rest.
While you’re looking closely, replace cracked caulk around windows and doors with a flexible, paintable exterior caulk. But don’t caulk the bottom edges of the panels or block any weep holes along them. Those openings let moisture drain from behind the siding.
Which colors and sheens suit aluminum siding?
Lighter colors are the forgiving choice. They stay cooler in the sun, show fading and chalking less, and suit the simple lines of post-war Capes, ranches and Colonials. Unlike vinyl, aluminum doesn’t soften in summer heat, so a darker color won’t warp it. Dark colors do absorb more heat, though, and tend to show fading sooner on south- and west-facing walls.
A few Sherwin-Williams colors that work well on aluminum siding:
- Light and classic: Pure White SW 7005, a soft white with a touch of warmth, or Alabaster SW 7008, a warm, creamy off-white, with Extra White SW 7006 on the trim for a crisp edge.
- Soft neutrals: Agreeable Gray SW 7029, a light warm gray, or Accessible Beige SW 7036, a warm greige that leans more beige.
- Gentle color: Sea Salt SW 6204, a pale green-gray, or Clary Sage SW 6178, a soft, muted sage.
- Deeper, with care: Evergreen Fog SW 9130, a gray-green sage, or Urbane Bronze SW 7048, a warm bronze-brown, with white trim.
For a front door or shutters against a light body, Naval SW 6244, a deep navy, or Rookwood Dark Green SW 2816 is a classic choice. Screens and chips mislead, so paint large samples on the siding itself, on a sunny wall and a shaded one, before deciding. Our guide to choosing exterior colors goes further.
For sheen, satin or a low-luster finish is the usual choice on siding. It sheds dirt better than flat without making dents and waves catch the light the way semi-gloss or gloss would. Flat hides the most but holds dirt more readily, and trim and doors can go a step glossier. Our paint sheen guide explains the trade-offs.
How do you make the paint job last?
Prep decides it. When painted aluminum siding fails early, it’s usually because of chalk left on the surface, a loose old finish, unprimed bare metal or paint applied in the wrong conditions. Our guide to why exterior paint peels covers the causes in more depth.
After that, upkeep is simple:
- Wash it gently each spring with a garden hose, a soft brush and a mild detergent, so dirt and mildew don’t build up.
- Touch up scratches and chips promptly, so bare aluminum isn’t left exposed. Keep leftover paint labeled with the color name and number.
- Keep gutters clean and downspouts pointed away from the house, so overflow doesn’t sheet down the siding.
- Check the caulk around windows and doors each year, and replace any that has cracked or pulled away.
Our exterior paint maintenance checklist walks through a full yearly routine.
Questions
Do you have to prime aluminum siding before painting?
Not always. If the factory finish is clean, chalk-free and holding tight, many quality exterior acrylic paints can go directly over it, so check the label. Bare, scratched or corroded spots need a primer made for aluminum, and a light film of chalk that won’t wash off may call for a primer formulated to bind it.
Can you paint aluminum siding a darker color?
Yes. Unlike vinyl, aluminum doesn’t soften in summer heat, so a darker color won’t warp it. Dark colors do absorb more heat and tend to show fading sooner, especially on sunny south and west walls. Test a large sample on the siding before committing.
Can you paint aluminum siding in cold weather?
Only within the temperature range on the paint label, and the siding itself has to be in that range, not just the air. Metal cools quickly late in the day and can collect dew before paint sets. In Michigan, that makes the practical season roughly late spring to early fall.