Faded, chalky aluminum siding can make an otherwise solid house look decades older than it is. Learning how to paint aluminum siding is one of the most cost-effective curb appeal upgrades you can tackle, transforming the exterior for $500 to $1,500 in materials on a typical home versus $15,000 or more for a full re-side. The key to a finish that lasts 15 to 20 years is thorough prep, the right primer, and a quality acrylic paint applied in proper conditions.
Inspect and Repair Before You Paint
Walk the entire perimeter and look for dents, loose panels, and oxidized spots where the original factory finish has turned to white chalk. Press your finger against the siding — if a powdery residue transfers, that oxidation must be removed or your new paint will not adhere.
Pop out small dents with a rubber mallet from behind the panel when access allows. Fill deeper dents or nail holes with an auto-body filler like Bondo, sanding smooth once cured. Re-secure any loose panels with aluminum siding nails spaced every 16 inches along the nailing hem. Replace sections with visible corrosion holes — patch pieces of matching aluminum siding are available at most building supply stores for about $3 per linear foot.
Cleaning the Surface
A pressure washer set between 1,200 and 1,500 PSI with a 25-degree nozzle removes dirt, mildew, and loose chalk efficiently. Mix a solution of 1 cup trisodium phosphate (TSP) per gallon of warm water in the pressure washer’s detergent tank. Start at the bottom of each wall and work up to prevent streaking, then rinse from top to bottom.
For stubborn mildew stains, scrub the area with a 3:1 water-to-bleach solution using a soft-bristle brush before pressure washing. Allow the siding to dry completely — at least 48 hours in moderate weather — before moving to primer.
Choosing the Right Primer
Primer is non-negotiable on aluminum siding. A bonding primer formulated for metal creates the adhesion layer that topcoats alone cannot achieve. Top picks include:
- Zinsser Bulls Eye 1-2-3 Plus: Water-based, bonds aggressively to oxidized aluminum, dries in 1 hour.
- KILZ Adhesion Interior/Exterior Primer: Excellent for chalky surfaces, resists peeling.
- Benjamin Moore Fresh Start High-Hiding Primer: Premium option with outstanding coverage on metal.
Apply one even coat of primer with a sprayer or roller. Coverage runs about 300 to 400 square feet per gallon. Let the primer cure for the time specified on the label — typically 2 to 4 hours before recoating and 24 hours before applying topcoat paint.
Selecting the Best Paint for Aluminum Siding
Use a 100% acrylic latex exterior paint. Acrylic flexes with the metal’s thermal expansion without cracking. Avoid oil-based paints — they become brittle over time on aluminum and are more prone to peeling.
Recommended products:
- Sherwin-Williams Duration Exterior: Self-priming on previously painted surfaces, excellent fade resistance. About $70 per gallon.
- Benjamin Moore Regal Select Exterior: Exceptional adhesion and color retention. About $65 per gallon.
- Behr Dynasty Exterior: Solid mid-range option with a one-coat coverage claim. About $55 per gallon.
Satin and low-luster sheens work best on aluminum siding because they hide surface imperfections while still being easy to clean.
Application Technique
An airless sprayer is the fastest method and delivers the most uniform finish on aluminum’s ribbed profile. Use a .015 to .017 tip and spray at a consistent 12-inch distance, overlapping each pass by 50%. Back-brush with a 4-inch brush immediately after spraying to work paint into seams and laps.
If you prefer rolling, use a 3/8-inch nap roller on flat sections and a brush for channels and edges. Two thin coats always outperform one thick coat. Wait 4 to 6 hours between coats in dry conditions. Expect to use 1 gallon of paint per 250 to 350 square feet of aluminum siding, depending on the color change.
Best Conditions for Painting
Paint when the air temperature is between 50 and 85 degrees F and the surface temperature is below 90 degrees F. Direct sunlight on aluminum panels can push surface temps well above the air temperature, causing the paint to dry too fast and leaving brush marks or roller stipple. Start on the shaded side of the house early in the morning and follow the shade as the day progresses.
Avoid painting if rain is expected within 4 hours or if humidity exceeds 85%. Morning dew can linger on north-facing walls until mid-morning, so test the surface with your palm before priming or painting.
Maintenance After Painting
A quality acrylic finish on properly prepped aluminum siding should last 15 to 20 years before needing a refresh. Wash the siding annually with a garden hose and soft brush to remove dirt buildup that accelerates fading. Touch up any chips or dings within a few weeks of noticing them to prevent moisture from getting behind the paint film. Store leftover paint in a sealed container for future touch-ups — label it with the color code and date.
