What Sun Does to Your Exterior Paint
May 22, 2013
We ask a lot of our exterior paint. Not only does it have to protect the wood underneath from the damaging effects of the elements so our homes stay safe and cozy, but it also has to make those homes look fresh and feel welcoming. When it comes to putting your home’s best face forward, exterior paint goes a long way. It pays a price, though. Constantly exposed to the elements, exterior paint is being relentlessly eroded, dried out, soaked, heated and cooled, chipped, and even changed at the chemical level.
Keeping the outside of your house looking good can feel like a never-ending job because it is. The sun, which we hope you see more often than not in your neck of the woods, is a major offender when it comes to aging exterior paint. The real culprit is ultraviolet radiation, which can break down the chemical bonds in house paint by initiating various complex processes that take place at the molecular level.
You can’t totally cancel out or reverse the affects of sun on exterior paint – except by repainting – but you can take steps to lessen the impact of the sun’s rays by choosing high quality paints with UV inhibitors. In any case, over time UV radiation acts on paint predictably, and here’s what you can expect if you go too long between exterior paint jobs:
Fading or Bleaching
The technical term for color fading caused by the sun is photodegradation. Dark colors are the most likely to fade noticeably, but even bright colors can change over time thanks to the effects of the sun on paint. Because fading and bleaching happen so slowly, you might not even realize that the color you loved five or more years ago is nothing like the color that’s on your exterior walls now. Most people only realize how extreme the color change is when they try to patch a chipped spot with their original color and find it no longer matches.
To the untrained eye, chalking can look like simple fading, but chalking is actually the result of a deep chemical change. UV rays cause molecules in the top coat of the exterior paint to transform, and this chemical change leaves behind a white film of dust over the wall’s surface. Chalking can make repainting a problem because new paint can’t adhere to the surface properly – special prep is needed before putting on new paint.
Blistering and Bubbling
A blister or bubble in your exterior paint means that the paint in that spot has lost adhesion – paint is either pulling away from earlier coats or from the painted surface. This is often caused by heat from the sun interfering with proper drying times. The best way to prevent blistering and bubbling is to never apply paint to a hot surface because paint will dry before it has adhered to the wall, causing all kinds of problems that lead to blistering and bubbling.
The sun can cause peeling in a few ways. Blistering and bubbling turn into peeling when the pockets pop, letting other elements into the spaces left behind, which gradually become larger and larger. When incomplete adhesion allows moisture to get between paint and the exterior wall surface, causing separation, the heat from the sun’s rays can make the problem worse, again leading to peeling.
The good news is that paint technology is always changing, and so many new paints have special sunproof additives that let you go a little longer before repainting. Still, the sun takes its toll in the end so until there are major advancements in paint tech, you’ll still need to repaint on a regular schedule that’s right for your home.
At Jerry Enos Painting, a New England painting company, we know the right products for the job. Every exterior painting project is different, and unlike other exterior painting companies, we will always treat your house or building as one-of-a-kind. Call us for a free estimate at 978-546-6843.
Categorised in: Exterior painting