Sunlight works a number on most materials and surfaces, especially when that sun is as powerful as what we get in the Phoenix valley. Heat and sunlight degrade plastics, wood, paint, and much more. The type of damage sustained depends on the type of material, intensity of the heat, and how long the material remains exposed. Luckily, there are ways to both restore the surface and prevent sun damage.

What Does the Heat Do to Exterior Surfaces?

The Phoenix valley has nearly 300 sunny or partly sunny days every year. And, with five months where the temps average 90 degrees or higher, you realize that the Valley of the Sun is aptly named.

Over time, the combination of sun and heat cause serious damage to the exterior surfaces of your home or commercial building. That damage not only looks bad, but it may even compromise the integrity of the structure. For example, plastic not only fades over time, but also becomes brittle. Wood, also, changes color in the sun while also becoming cracked and warped.

Painted surfaces also take on a faded, chalky appearance, especially for west- and south-facing walls. Certain colors, such as reds, blues, and yellows, are more prone to fading, particularly in direct sunlight. The quality of the paint also degrades, causing it to chip and peel.

It isn’t only your walls that take a beating in the heat. Any wood or painted surface feels the sun’s destructive power, including doors, gates, and trellises.

Refinishing Natural Wood Surfaces

When natural wood surfaces become discolored due to sun exposure, you must first sand the piece to bring the wood’s color back to the surface (in other words, sand away the bleached or discolored wood).

Refinishing is easier – and creates a better product – You may first remove the item to be refinished. This means taking a door or gate off its hinges and setting up in your work area, preferably on a sawhorse. Working on the item while it stands upright may causes dripping and a ruined finish if not done properly.  Laying it flat guards against that while also giving your back a break.

It usually takes at least two days to complete a refinishing project, so time your work so that the item is dry at the end of the day, allowing you to re-hang it overnight or apply the finish coat.

Place the door or gate across your work surface and then begin sanding. You may sand by hand, but it goes faster with a vibrating sander. If hand-sanding an item with raised panels or other features, use sanding sponges to more easily reach spots that you can’t reach with stiff sandpaper.

If you sand all the way down to raw wood (meaning you sand away all of the finish), you need to reapply varnish. Use Marine Varnish, which has offers excellent UV protection and slows sun damage. If the item is painted, apply a coat of primer after sanding before using an exterior grade enamel paint.

Whether painting or varnishing the item, allow it to dry completely before applying a second coat. If the first coat feels even a little bit tacky, it’s too early to apply another.

Protecting Exterior Painted Surfaces

Fading is the first sign of sun damage, but it isn’t immediately noticeable, since fading occurs over time. This makes it a challenge to address damage when it’s easier. In other words, early.

Please note that chalking and fading are two different things, though chalking resembles fading. Chalking occurs when the paint surface forms a powdery residue and is the result of a chemical reaction (though also associated with heat exposure). Fading is the gradual lightening of the paint’s color. Chalking doesn’t always require repainting, but does require a binding primer before repainting is done.

Though all exterior paint fades eventually, you can help prolong the inevitable to keep colors looking fresh for as long as possible. Start by using fade-resistant paints. This solution seems obvious, but it’s one that many people avoid because fade-resistant paints cost more. That higher cost is because these paints contain quality pigments along with sufficient binder. This combination creates durable colors and paint that adheres well to the surface.

Lower quality paints began degrading within a few months of application while high quality 100% Acrylic Latex paints offer excellent color retention. Like everything else, paint technologies and products improve and evolve. Extend the life of your painted surfaces by investing in high quality paints, preparing the surface, and using optimum application methods.

You should also consider inorganic pigments over organic ones, such as browns and beiges over bright colors, as these offer greater stability. Brighter colors, such as red, yellow, and blue, are more vulnerable to UV rays and therefore more prone to fading.

Also, pay attention to those things over which you have no control. This includes the weather and the amount of direct sunlight your property gets. For example, lighter colors absorb less sunlight than darker colors, leading to less fading. You can also choose paint with a high gloss finish, which reflects more light than flat paints, further reducing the amount of UV light absorbed. Another common issue is paint that reacts poorly with the surface. For example, new masonry is also highly alkaline, so avoid alkali-sensitive paints in these situations or use a primer to block alkali properties.


Over time, sun and heat damage wood and painted surfaces. You can take steps to prolong these surfaces with UV-resistant products. Also, consider protecting the surfaces themselves from the sun by extending rooflines, installing awnings, or planting trees (or all of the above). Finally, when it’s time to repair, invest in quality products.

Not sure whether the time has come to repaint or refinish? Contact CBP of Arizona for a free estimate.