A Closer Look at TopCoats

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As a product category, exterior trim paints are one of the fortunate beneficiaries of all the manufacturer R&D dollars going into waterborne/latex technologies in the past several years. While oil stains were historically effective on exterior siding applications, they were never exactly a standard for exterior trim. Latex exterior trim paints have always been around. In the past, they held up well but could be difficult to work with. Some products in the new latex era have struck a better balance of performance and user friendliness.

You can call them waterborne, acrylic or latex. By any name, exterior trim paints are all about performance, and that is measured for the most part by durability – the ability to withstand all the elements that exterior wood trim surfaces endure day in and day out, through all the seasons. Durability is the umbrella under which several other measurable qualities fall.


These days you can make just about any exterior trim paint look good on a house. The technologies have come that far in ease of use. So aesthetics don’t need to weigh as heavily in the assessment of exterior trim paints, with the possible exception of noting how sheen qualities and color retention compare across different lines and manufacturers. When we look at any product type, we always end up with a series of questions. With most paint or finish products, the questions usually begin with the word “how.”

Here is an example of five questions, each of which you will find can pretty easily lead to five more.

The First Five Hows of Exterior Trim Paints

  • How does it apply by three methods (brush, roll and spray)?
  • How does it dry?
  • How does it adhere (to primer, to itself and to existing coatings)?
  • How does it sand?
  • How durable is it?

Notice that our questions are not only “how” questions, but also “how does” questions. These are the types of questions that seek to discover how paint behaves. Each of these questions easily breaks out into a whole series of other questions within the initial question, but in general terms, these are the criteria that are important to consider in exterior paints. More often than not, a product will excel in a couple of these categories but not measure up in others. It wasn’t so long ago that exterior latexes would struggle in several of these areas, but these are basic requirements in today’s paint world. If a product cannot meet a minimum standard in each of these qualities, then it should probably be excused from consideration.


Most of us who were painting in the ’80s and ’90s know that latex paints took a bit of a deserved bad rap for being rubbery, sticky and difficult to apply. While a rubbery quality may have been OK for its flexibility on surfaces that constantly expand and contract, as exterior trim does, it was not OK for the “user experience.” And while “sticky” was probably good for adhesion, it wasn’t good for application tools or flow. These paints were difficult to use – thick, heavy, hard to spread by most application methods and just about impossible to use when surface temperatures were anything but cool … not to mention using them in direct sun.

My painting company has put many exterior trim paints to the test in the past decade on both new homes and repaints. When product technologies are in transition, which they constantly are, we try to avoid “putting all our eggs in one basket.” We use a variety of different products and equal product lines across different manufacturers in order to assess who is doing what in the advancement of these technologies. When technologies change, especially under legislative pressures, each manufacturer seems to put its own spin on “new.”


Sherwin-Williams calls this exterior formulation an acrylic latex. Duration has been one of the exterior trim paints that my company has been using for the past several years. We consider Duration to be a great example of high-performance exterior trim paint that has proven to be successful on both new construction painting and residential repaints, because the answers to the “how” question list have proven just about every time to be exactly what we, and most painters who deliver productive quality, seek in exterior trim paints.


By brush, roller or sprayer, Duration encourages the user to move quick. In other words, it is not a product that will slow you down. This is where people struggle with Duration. It is on the thicker end of the medium-viscosity latex scale. It holds and releases well by brush, loads and levels by roller, and is a particularly good performer in sprayed applications, where we have consistently experienced it to level at a near-interior trim paint standard. If you have visited our YouTube channel in the past few years, you have no doubt seen Todd spraying miles of Duration satin in horizontal applications on exterior trim packages as a benchmark paint for air-assisted sprayer testing. That’s how much we came to think of it. The reason is – it just plain works. Our company has prefinished trim packages for several new construction projects in recent years using Duration. In every case where we prefinished trim packages, we installed three-coat systems of sprayed latex primer and sprayed the first coat of Duration in the shop, followed in the field with brushed (or rolled and backbrushed) coats after trim installation in the field. We have prefinished, conservatively, dozens of miles of product using Duration with few glitches.


Some painting contractors over the years have complained that Duration dries so fast that it is difficult to spread manually and the paint is challenged to level before tacking up. This is a situational characteristic. If surfaces are smooth, Duration spreads fine. Duration stays wet long enough to manipulate by any of the three application methods, and it is one of those acrylics that continues to lay down and level long after initial tack up – a very desirable quality in an exterior trim paint. With latex paints in general, there are several drying stages. Tacking up is the first stage and it is relatively quick, which prevents surface imperfection from airborne contaminants. That is actually a strength. On the backend of the drying process, this is not a latex that will stay sticky for six days. Worst case we observed was spraying to heavy mil thickness in humid conditions, in which case, 48 hours would be desirable prior to sanding surfaces or stacking boards that had been sprayed. On average, 24 hours is realistic. In the field, 20 minutes before light rain was a safe amount of time. This is good across-the-board drying performance – again, still leaving you with a workable product.


In a word – excellent. Because we have been observing this product for over three years on initial coating systems that we installed, we have been able to observe product performance in harsh New England exposures. We have seen what these elements can do to unprepared products. Duration’s adhesion runs deep. We have not seen it fail at all. Again, keep in mind that we build three-coat systems correctly. Duration in a three-coat system experiences subtle fading as it weathers, but it is not inclined to peel, flake or blister. It builds well and holds up well in a three-coat system. Adhesion to primers and to itself is better than the average acrylic. Also worth noting is the coverage factor. We have routinely put white Duration over funky colors with ease. Exceptional coverage paired with great adhesion make this a product worth taking the time to understand.


While some latexes are sanding abrasive destroyers, Duration (with proper dry time) does not gum up or load sandpaper. From a practical standpoint, the sanding factor occurs in between the first and second coats of finish. In-between coat sanding, whether manual or by power sander, is easy with this paint. No nonsense; it just smoothes out. We have also done more aggressive material removal sanding with Duration to see how it breaks down and strips. Even in stilted dry time scenarios, we have not found Duration to want to go “rubbery.” That said, it is not an easy product to remove; it is rather toothy.


Obviously, it holds up, ages gracefully and is well-built for success in extreme exterior conditions. Further, some of the durability nuances in which it excels include sheen retention and color retention. Even after two to three years of exposure, we have found Duration to be easy to clean and maintain. Even in a satin finish (as opposed to other latexes in semi-gloss), Duration maintains its composure over time very well. We have found that in building a three-coat system with Duration, it is best to apply the first finish coat over primer on the heavier side. This is where the bulk of the coverage, adhesion and body for durability is established. The final finish coat can be lighter, more like a “tip off” coat that just gets the surface wet and puts a shine on it. While the final coat does build some of the overall coating system thickness, it is really just a cosmetic round.

While it seems that there are new and improved waterborne and latex formulations rolling out just about daily, there are some current-generation coatings that are still quietly going about the business of protecting surfaces and looking good in the process. Duration exterior satin is one of them. APC

Scott Burt is the president of Topcoat Finishes, Inc., in Jericho, Vt. He enjoys communicating with contractors and manufacturers at topcoatreview.com.


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