Exterior Paint

Home | FAQ | Finishing | Sump Pumps | Foundations

If you must paint, or are one of those rare individuals who actually likes to spend weekends painting, there are enough different brands and formulas to keep you busy for several years just selecting one “best” for you. In an effort to guide you to the “best,” attempts are routinely made to test various paints (see the table “Outdoor House Paint Performance Tests” from Rodale’s New Shelter, now titled Rodale’s Practical Homeowner magazine). But usually the results are not very helpful because there are so many different kinds of paint. Competition between paint companies is keen, and manufacturers are constantly coming up with new formulas that make tests pretty obsolete by the time consumers become aware of them. The bottom line is that, for the most part, paints within the same category and price range are about equal.

The carrier for latex or water-based paint is water. I doubt if it makes much difference if it's water from New York or water from New Mexico. The carrier for oil-based paints is petroleum distillates or paint thinner, and there’s no significant differences in these. I have not heard any paint company touting the quality of their carrier yet. As for pigment, if one company has discovered a source of red with particularly good hiding characteristics or staying power, the other chemists will be on it quickly That leaves the third ingredient of paint, the binder, which gives it adhesive power. In water-based paints, the binder is a latex resin. In oil-based paints it's usually linseed oil, and I have never heard anyone try to claim his linseed oil was better than someone else’s. There can be differences in the resin binders, as new, stickier substances are concocted, but discerning that difference is beyond the ken of the layperson who must either rely on an honest paint dealer who knows (there are many honest paint dealers, but not so many who really know) or a chemist or experience. Generally speaking, higher-priced paints are more durable. If you buy cheap paint, expect to paint again. Soon.

Actually, the condition of the surface to be painted is more important than the paint. The surface has to be dry and reasonably clean. And the surface has to stay dry. Peeling paint is rarely the paint’s fault. Rather, it's moisture oozing out of the walls, either because the wood or whatever was not dried out in the first place, or because the lack of a vapor barrier is allowing humid inside air into the outer wall where it condenses upon meeting cold air. Paint will almost always peel from soffits that are unventilated. In addition, many finishing paints must be primed before they will stick well. Using two coats of paint instead of a coat of primer and then a coat of paint is not the same thing. Directions on the label tell us all that kind of mundane information but we don’t pay attention. We know we are supposed to scrape off all loose paint and dirt, but we often do so only carelessly. We just can’t wait to start painting. So it's not a very long wait before we have to paint again.

I include the table “Outdoor House Paint Performance Tests” mostly for its data on the effect of acid rain on paint, a subject about which little solid information is yet available. These tests were run by Dhirendra C. Mehta of the Rodale Technical Group, under the direction of Mark Kern. Paint samples on pine blocks were sprayed in cycles with a sulfuric acid solution equivalent to about a year’s worth of acid rain and chemical pollution. White oil-based paints suffered most, turning a pale pink. Dark oil-based paints like the high-grade reds from Glidden and Kelly-Moore resisted acid rain as did all the latex paints, especially high-grade ivories from Dutch-Boy, Glidden, and Pittsburgh, as well as high-grade red from Sherwin-Williams.

Of course, the proper response to acid rain, which can make a joke of the search for low maintenance, is not so much finding materials resistant to it, but demanding that the problem be addressed adequately. Call it low-maintenance politics.

Outdoor House Paint Performance Tests








Top of Page Home Prev: Log Exteriors Next:  

Updated: Thursday, March 5, 2009 18:45