Repainting Aluminum Siding & Trim

Do You Have These Common Questions?

I am often asked several questions over and over again by property owners. The first being, “Should I repaint my aluminum siding?” Or maybe, “Can I repaint my vinyl siding?” No matter the specifications of the job, customers never fail to ask, “How long will my paint last?” 

These common and very important questions deserve answers. If most of my customers are asking these questions, then it can be safe to assume you have the same questions! Let’s explore and answer them now! 

Aluminum Siding: Painting & Longevity

Aluminum siding is made up of a thin sheet of aluminum that is coated with a baked-on-finish on one side that is designed to last for 20 years. Some of the older factory baked coatings applied to siding were designed to breakdown when exposed to UV rays from the sun and wash away in the rain to be “self cleaning.”  Most of the higher quality new aluminum siding and trim is coated with Kynar. The new systems made with Kynar are hydrophobic (much like a teflon pan), which allows for the same self-cleaning abilities as the older coatings, but with added durability and longevity. Some cheaper new metal is coated with vinyl, which delaminates, peels off,  and weathers similarly to the old coatings. All aluminum siding and trim will oxidize once it has weathered and the bare metal is exposed. Therefore, it is important to keep it covered and protected. Oxidizing aluminum turns white, as opposed to steel, which turns a brown or rust color. However, just like steel, when aluminum experiences severe oxidizidation, it will form pits and eventually holes. 

All aluminum can be painted fairly easy. Want to hear even better news? When coated properly, aluminum will last 15 years or longer, depending on the color. White and lighter colors will last the longest, while dark and bold colors do not last as long. UV rays “bounce” off lighter colors, but are absorbed by the darker colors. The more UV rays that bounce off instead of absorbing into the aluminum, the longer the paint will last. This explains why the lighter colors last longer than the darker colors.

The system for painting aluminum siding and trim is as follows:

1. First, the surface must be pressure washed to remove all chalky residue.
2. If it is a new un-weathered Kynar, it needs an oil-based bonding primer applied (especially on a horizontal surface).
3. If it has been weathered, any good 100% acrylic paint will work properly, as they are all self-priming.