For an exterior, waterproof finish that holds up against heat and cold, sunlight and rain, many contractors choose elastomeric paint.
These paints create a thick coating that adheres to most masonry surfaces, such as concrete block and stucco, as well as wood and T1-11 siding (plywood siding). The paint helps fill and repair hairline cracks (so long as these cracks are non-structural). Elastomeric paints, when correctly applied, are around 10 times thicker than traditional acrylic exterior paints.
Why Choose Elastomeric Paint?
The thick coating of elastomeric paint makes them ideal for many outdoor applications, especially in areas with extreme weather. The paint bridges cracks smaller than 1/16″ and helps cover other surface imperfections. For larger cracks, first repair the crack and clear the paint surface of debris to ensure proper adhesion.
Elastomeric paint has an elasticity that helps it withstand contraction and expansion in the underlying materials. Its waterproof nature also helps it resist fungus and mildew.
Though recognized for its effectiveness on masonry surfaces, including crack-prone stucco, it also works well on wood and T1-11 siding, both of which tend to crack over time. The waterproof properties of elastomeric paints keep water from penetrating these cracks and damaging the structure.
Elastomeric paint also lasts much longer than traditional acrylic paints, and only requires two coats to achieve amazing coverage. The dry film thickness (DFT) of elastomeric paint ranges between 10 and 20 mils, compared to 2 to 3 mils with acrylic paints.
The Cons of Elastomeric Paint
The main con of elastomeric paint is its cost. Per gallon, it costs about the same as quality acrylic paints. However, the amount of coverage you get for that same amount of paint is significantly less.
A gallon of elastomeric paint covers, on average, around 75 square feet when correctly applied. Compare this to the 200 square feet of coverage you get from a gallon of conventional paint, and you need four to five gallons of elastomeric paint to get the same amount of coverage.
Another challenge is removing elastomeric paint, should you want to repaint or complete repairs. This is an extremely heavy paint, designed to withstand extreme weather conditions. It does not come off easily. In addition, repairing issues that occur during application presents difficulties. Again, this is due to the paint’s thickness. If you experience dripping or a bare patch with a traditional acrylic, performing adjustments is fairly simple. Similar repairs with elastomeric paint are much more involved.
Applying Elastomeric Paint
Applying elastomeric paint really requires hiring a painter experienced in painting with elastomeric products, thanks to the numerous challenges involved. First, temperature plays a large role, as too-warm temperatures cause the paint to run, effecting both drying time and uniformity in appearance.
Adherence requires a clean surface. If any repairs are required, thoroughly clean the repair area of dirt and debris before applying paint; otherwise, the paint will not adhere correctly and may bubble or peel.
Some people attempt to extend the coverage of elastomeric paints by thinning them with water, or using too little paint for an area. The result is a ropey, lumpy texture. To achieve the true waterproofing qualities (and why else would you spend the extra money on elastomeric products?) you need to apply two coats, using a sprayer at the right setting and then back-rolling to achieve the right look.
So, Is it Worth the Extra Cost?
The answer really depends on your needs and preferences. If you want an exterior paint that lasts a decade or more, that stands up against Arizona’s fierce sun, intense dust storms, pounding monsoon rains, and shifting landscape, then elastomeric paint is worth the extra cost.
However, if you repaint every few years or your budget forbids the extra expense, a quality acrylic offers excellent coverage for about half the cost.
If you’re considering exterior painting and want to learn more about your options, contact CBP of Arizona today for a free project estimate.