Commercial Paint Problems & Solutions – Excessive Chalking

Whether you’re dealing with commercial painting or residential painting.  Chalking is a frequent problem that occurs in the aging paint field.  What’s worst is that by the time it occurs, you need to increase the amount of prep required for the job.  So here’s how and why you need to be proactive before chalking occurs.

Here’s How Paint Begins To Chalk

You can take all the time in the world to meticulously apply and brush a flawless coat of paint.  But no matter how careful and tedious you are, your coating will eventually break down.   There are many elements that can break down a coating.  But the most hazardous are ultra violet rays.

Excessive sun exposure can be a mortal enemy to inadequate coatings.  Too often, alkyd, or oil-based, coatings are applied outdoors, putting a vulnerable coat in front of the ultra violet rays.  The UV breaks down the binder in the paint, which is what holds the paint molecules and pigment together.  As the binder starts to degrade, the powdered pigment used to tint the material is released from the coating, in a dry, chalky state.

And oil paints aren’t the only vulnerable coatings.  Epoxy coatings are just as vulnerable to UV rays.  In fact, Corrosionpedia implies that epoxies break down faster than oil based paints, with some epoxies breaking down as quickly as 50 hours in direct, constant exposure.

So what’s a painter to do with exterior painting?

Firstly, choose the best performing paint.  And since we know that UV rays are the main cause of degradation for coating binders, you’ll want to find something that is UV resistant.  Latex paints aren’t completely UV resistant, but they can tolerate alot more UV exposure than oil and epoxy paints.

But if you really want to go balls-to-the-wall, then consider a urethane paint.  Urethane’s are UV resistant, and can offer excellent adhesion.  One of our most commonly used urethane paints is PPG’s Durethane.  

Now, this isn’t a paint you’ll want to use for your house.  This is a coating that is used on metal substrates in industrial environments.  It also costs over $100 per gallon.  So although it’s unlikely you’ll need to use something of this calibre, you never know when you’re going to have some metal to coat.

But if chalking really that bad?

No.  Chalking is not that bad.  A small amount of chalking can actually help deter mold, fungus, dirt, and other types of debris that can impair your coating system.  When rain hits a chalky surface, the rain water will wash away the chalk, and any dirt clinging to the chalk.  But you’ll notice, if your chalky surface is directly above masonry, that the chalk will wash onto the masonry, and discolor its appearance.

So in situations like this, chalking is not desirable.  And if the chalking gets tot he point where it covers your entire hand after rubbing the surface, then it would be good time to consider repainting the area.

How To Re-Paint Chalking/Powdering Paint

Just like any debris, the chalk residue needs to be removed.  Pressure washing is going to be the easiest way to remove the chalking.  However, if you don’t have a power washer available, then you can use a stiff brush, water, and mild detergent.  Then a simple garden hose will provide enough power to remove the chalky residue.

Overall, chalking leaves a poor appearnace on colors that aren’t white.  But if you’re using white, then chalking doesn’t appear as quickly, and you can benefit from the color tone by allowing it to prevent mold and dirt from adhering to your surface.