Tolbert Painting: when to use elastomeric paint?
A common question that potential clients bring up during initial talks about an exterior projects is: “Would you recommend elastomeric paint?” The answer is yes and no.
When if first came out, elastomeric paint was designed to waterproof stucco and it had very specific guidelines for how to achieve a watertight application. Since then, the product has been altered, it can be used for various applications, and each paint company has its own version.
Some elastomeric paints still stand by the waterproof warranty and the requirements for this process are mostly still the same. In this case, the surface should be stucco, free of other paint (meaning never painted before), cleaned of debris and mold, and primed. The elastomeric paint should be applied at 12 to 18 mils thick when wet in two coats to leave a dry mil thickness of 16 to 20, with a minimum number of 10 pock marks per 12” square on the surface.
Unless you have major leaking issues on your home, this process is overkill. What made this process popular when the product was introduced to the residential market in the 1990s was stucco cracks. Foundations settle or an occasional 3.4 earthquake rolls through, leaving no stucco house on the Central Coast exempt from some sort of cracks. So the local paint representatives began to market Elastomeric paint as a solution to this problem. Unfortunately, there is no real solution to prevent a moving void in a wall. The house settles, a void is created, and there just isn’t an application on earth strong enough to glue a house together (and paint was never intended for that purpose anyway).
The purpose of paint is to protect the surfaces of the building materials that make up the design of your home. If cracks or separation occur, it is a result of faulty construction or forces of nature beyond our control. When voids are created they can be filled to prevent further erosion of the paint finish or building surface.
That being said, there are times to use elastomeric paint. If a stucco home has never been painted and has a web of thin cracks, known as Spider cracks, then an Elastomeric paint might be a good choice because the paint is a thick viscose and would be able to fill those small voids. If a stucco house has been previously painted then Elastomeric is not recommended because of “surface tension”, which is created when the top coat begins to expand and contract creating tension on the previous coat of paint, eventually causing it to pull away. Some older houses (made before the 1960s) have plaster on the exterior (often if not made of wood), and elastomeric should never be used on old plaster because of surface tension as well.
Elastomeric paint can be a good choice for a stucco house but might not be the best choice. I recommend you consult with a paint professional you trust to evaluate the surfaces of your home and find the best products that work for your home and environment.
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