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In ancient times two Greek cults vied for dominance. The one, devoted to Apollo (the "Apollonians") was devoted to order, simplicity, and conservatism. The other, devoted to Dionysus (the "Dionysians") embodied emotional abandon and extreme liberty. We've seen a swing between these extremes in our culture: Sometimes a swing towards conservatism (think of the norms and hairstyles of the 1950s), and at other times a swing towards Dionysian abandon (think of the life and hair styles of the late 1960s).
There are also swings in the painting industry. Traditionally, stucco and masonry buildings were coated with acrylic latex. But from the mid-1980s to the mid-1990s the coating of favor for these surfaces was Elastomerics. Elastomerics are heavy-bodied acrylic coatings that can bridge small cracks, repel water, and retain their flexibility for many years. They seemed like the silver bullet for weatherproofing against soggy weather.
How times have changed! Elastomerics, once seen as a cure-all for almost any leaky situation (including bad building design, compromised caulking, and leaking flashings), are now in some disfavor. Specifiers and property owners are concerned about the limited "breathability" of these coatings, and the possibility that they may trap moisture vapor inside of walls and promote wood decay and mold. Many have swung back to conventional acrylic latex with its better breathability, but limited water repelling qualities.
But, of course, not all Elastomerics are created equal; nor are all latexes. To look at just one criteria, in Elastomerics there are considerable differences in permeability ratings (the higher, the bette,r as it lets the wall breathe), and in acrylic latexes, different products have different percentages of Acrylics (again, higher is better).
Another classification of coatings, called "high build" acrylics, combines some of the best characteristics of conventional latex (breathability) and elastomerics (water repelling qualities and crack-bridging abilities). Perhaps on the pendulum "swing" between the Apollonians and the Dionysians, high build acrylic for stucco and masonry represents a balanced middle point.
This information comes from a recent article by Remdal Painting & Restoration. To discuss the advantages of professional painting & restoration services (exterior painting including high-build and elastomeric coatings, interior painting, concrete restoration, water damage, caulking, deck membranes, deck restoration, etc.), contact us at 604-882-5155 or visit us at www.remdal.com.
article at HomeRenovationGuide.com