Installed far and wide from the 1940s to the early 1980s, aluminum siding is still found on many homes. That aluminum siding is still performing after decades is a testament to its durability, low maintenance, and resistance to fire, insects, and rot. But eventually, aluminum siding can become worn, faded, or dated, so it's time to paint it.
With the right prep work—including patchwork, cleaning, and primer—even the oldest and most faded aluminum siding can be revitalized with a fresh, beautiful coat of paint.
Working With Aluminum Siding
Painting aluminum siding is different from painting other siding materials because of the nature of the material. Aluminum has oxidation and corrosion characteristics that may be unfamiliar to many homeowners accustomed to dealing with wood, fiber cement, or vinyl siding.
While it's advisable to clean surfaces before priming or painting, you'll want to put even more time and vigor into cleaning aluminum siding. Dusty gray or white oxidation on aluminum isn't easy to remove with pressure-washing alone. Enlist the help of a nylon-bristle scrub brush, scrub pad, bucket, and a mild homemade cleaning solution.
Aluminum Siding Cleaning Solution
- 1 cup of household bleach, unscented
- 1 cup of TSP
- 1 gallon of warm water
Mix slowly in a clean bucket to avoid splashing. Make sure that the TSP granules are fully dissolved in the water.
Aluminum siding is treated in the factory with two to three color coats, then baked at extremely high temperatures to produce colors that resist fading and peeling for years. There is no need to remove this factory-finished paint before you paint the aluminum siding.
But if the siding's factory paint was painted later on, that paint may need to be stripped off. While you may not need to strip off all of the paint, sections that are peeling or cracked should be removed.
Professional painters tend to prefer oil-based primers for priming aluminum siding before painting. Though water-based primers are good for other materials, oil-based primers offer the toughness and the adhesion properties needed for dealing with aluminum. Plus, oil-based primers won't react with aluminum.
Oil-based primers are more difficult to work with than water-based primers. They need to be cleaned with paint thinner or mineral spirits, not with water, and they cure at a far slower rate than water-based primers. But their long-lasting qualities more than balance out their difficulties.
When to Paint Aluminum Siding
Aluminum siding is best painted in dry, warm seasons. Paint during the early part of the day, before the sun begins to shine on the siding. Avoid painting when it is rainy or overly humid. Optimal humidity is between 40 and 50 percent.
If the aluminum siding was previously painted with lead-based paint, hire a remediation company to remove the paint safely. Use a lead paint test kit to determine if the paint contains lead.
Equipment / Tools
- Airless paint sprayer
- Paint roller
- Roller pads
- Extension pole
- Kitchen gloves
- Extension ladder or 6-foot ladder
- Caulking gun
- Putty knife
- Abrasive scrub pad
- Nylon bristle brush
- High-quality exterior paint
- Oil-based primer
- TSP (Tri-sodium phosphate) or safe TSP substitute
- Painter's tape
- Masking film
- Exterior caulk
- Acrylic latex exterior filler
- Paint thinner or mineral spirits
Repair or Patch
Tiny holes and cracks should be filled with paintable exterior caulk. Caulk around windows and doors. Small holes in the siding should be patched with a sandable, hydrophobic acrylic latex exterior filler. Do not use wood filler. Patch large holes by cutting small sections of aluminum with shears, then applying them over the hole with exterior filler or gutter sealant.
Pressure Wash Siding
Attach the pressure washer to an outside faucet and to a GFCI outlet. Spray from the top downward. Never spray upward, as this may force water behind the siding. Remove large pieces of debris like spider webs, dirt, and dust.
Do not use a fine-spray nozzle when pressure washing aluminum siding. The material is soft and can be dented or etched with a concentrated spray.
Clean Siding by Hand
Mix up a cleaning solution. Wearing kitchen gloves, scrub the aluminum siding by hand, starting at the top. Use an extension ladder or 6-foot ladder to reach the top. Scrub areas that are about 3 feet wide. When you reach the bottom, rinse off the section. Move to an adjacent section and repeat.
Mask off Areas
Mask off all sections that will not be painted. These may include windows, doors, outlets, lights, light switches, electric or gas meters, air conditioners, or mailboxes. Use painter's tape for small areas. For large sections, use masking film attached with painter's tape. Lay down a drop cloth over pavement and foliage.
Mix the primer well. Insert the airless paint sprayer's draw tube in the bucket. Fully masked and wearing goggles, spray in sections of about four feet by four feet.
Let the primer cure for at least one hour. Clean out the paint sprayer gun and hose. Switch to the paint. Spray the paint similar to the primer, in small sections.
Back Roll Paint
Immediately after finishing a section, back roll the paint with the paint roller to even out the primer consistency and to help the paint stick better.
It's faster to have two people doing this job. One person sprays, while the other person follows by back rolling.
Apply Second Coat
Let the paint cure for at least 2 hours. In moist air or cool temperatures, let the paint cure longer. Apply a second coat of paint to the aluminum siding.
When to Call a Professional
Call in a professional painting company if you feel that the job is too large to manage. Exterior painting isn't particularly complex, but it is time- and labor-intensive. Pro painters can usually paint an entire house in just a few days or week, depending on the size of the house.