How to Prepare to Paint Aluminum Siding

To paint aluminum siding, relatively little prep work is needed. Much like painting the interior of the house, the surface must be cleaned and primed with an appropriate primer. Even if the aluminum is older, or already has paint which is flaking away, the process is basically the same.

Step 1 – Cleaning

Fill one 5 gallon bucket with warm soaping water and scrub down the sides of the house with the scrub brush. Scrubbing will help flake off any loose paint and clean the surface at the same time. Wait 2 to 3 days for adequate drying before applying the primer.

Step 2 – Primer

In the second 5 gallon bucket, mix one pint of paint thinner to one gallon of oil-based primer. Latex primers contain ammonia which reacts with oxidized aluminum and creates tiny little bubbles in the primer. Apply the oil-based primer mixture evenly with the paint brush.

Step 3 – Dry Time

One of the most common mistakes for painting aluminum is inadequate drying time before applying the latex exterior paint. Wait at least 2 to 3 days before applying any top coats of paint. Even if the primer appears to be dry, continue to wait.