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Quick Links: Kitchen Remodeling | Basements | Decks & Patios

Choose The Right Exterior Primer, Paint Or Stain

Whether you're coating a deck, a fence or whole house, there's a right and a wrong product to use.

Misconception:   All paints are basically the same, so buy the cheapest

Truth:  Don’t fall for this one. All paints have the same types of ingredients, but the quality and performance of those ingredients vary significantly. Better-quality paints have better resins and more of them, so the paint adheres better and lasts longer. They have higher-quality pigments that cover better and are less likely to fade. And they have additives that help you brush them out faster and smoother. All in all, the ingredients in higher-quality paints cost more, and you won’t find them in the cheaper paints.

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Misconception:   It’s best to paint your deck with an opaque stain

Truth:  Solid stains are a good choice for smooth outdoor surfaces like siding and deck rails, but they’re not a good choice for decking. The wood won’t absorb enough stain to withstand the abrasion of foot traffic and it’ll soon show wear. Semi-transparent stains or tinted sealers are better choices because the wood will absorb more stain, giving it better protection. Still, you have to clean the wood and renew the stain every two to three years.

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Misconception:   Oil primers are better than latex primers on bare wood

Truth:  In general, both oil and latex primers work well on bare wood. But in some cases one works better than the other. An oil primer will work better than latex on new wood that has a “mill glaze,” that is, a polished surface caused by the planer during the smoothing process. You can usually spot the shine if you examine the wood closely (see above). Or sprinkle a little water on the surface. If it beads up rather than sinks in, choose an oil primer, since the wood will usually absorb it better than it does latex. If you want to use latex, first sand to dull the shine.

A latex primer will work better than oil to “spot prime” knots and pitch pockets (dried). Choose a special “stain blocking” type for this purpose. Once the spot priming dries, prime the entire surface with an oil or latex primer.

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Misconception:   Outdoors, oil stains are better than latex stains because they last longer

Truth:  It depends on the surface. Oil stains generally penetrate wood better than latex stains and perform best on rough surfaces like rough-sawn wood and cedar shingles, which will soak up a lot of stain. Semitransparent oil stains excel here because you can apply several coats and achieve good wood protection without hiding the natural texture and grain. You can expect the stain to last from four to seven years. They’re easier to renew, too. You can simply power wash to clean and recoat.

However, latex stains (especially solid ones) excel on smooth wood surfaces. They won’t erode as quickly as oil stains.You can expect a solid latex stain on smooth, vertical wood to last four to six years. Keep in mind that no stain will last more than two to three years on horizontal surfaces that are exposed to the sun and rain.

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Misconception:   You don’t have to reprime factory-primed building materials

Truth:  Beware! Sometimes the manufacturers of siding and other materials prime their products only to protect them in transit and on the job site. The coating isn’t always intended to be the base coat for paint. To determine if you have to reprime, read the manufacturer’s finishing recommendations for the product you purchase.

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Misconception:   You shouldn’t put an oil primer over latex topcoats

Truth:  Generally speaking, applying oil primer over latex isn’t a problem. A clean, solid, well-prepared base for the new paint is the most critical issue. However, several situations specifically call for an oil primer.

1. If the old topcoat shows significant chalking, that is, the pigment comes off on your finger when you rub the topcoat, then scrub the surface well using a detergent and brush, rinse and apply an oil primer when the surface thoroughly dries.

2. If the topcoat shows extractive staining (watersoluble substances in cedar and redwood; photo above) bleeding through the surface, scrub, let dry and prime with a stain-blocking oil primer.

3. If you spot wax bleed on older types of hardboard siding, thoroughly scrub the surface and apply an oil primer. Heat from the sun sometimes causes the wax used as a water repellent to migrate to the surface and create a dark, blotchy appearance. Then apply 100 percent acrylic latex topcoats to yield the best long-term durability.

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Misconception:   You can’t paint treated wood

Truth:  Actually you can paint treated wood, but you may not like the results. The decay-resistant chemicals won’t harm the wood’s ability to hold paint. However, treated wood is usually a lower grade. It has knots, cracks and other surface flaws that a paint film tends to highlight (see photo). A semitransparent stain is usually a better choice because it emphasizes the natural “rough” character of the wood.

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Misconception:   You can’t paint wood once you’ve applied a water repellent

Truth:  Using a water repellent on bare wood in areas vulnerable to moisture—such as windowsills, trim and siding near the ground, and board ends in exposed locations—is the best thing you can do to prevent peeling and extend the life of your paint job. Unfortunately, paintable water repellents can be difficult to find. Don’t paint over a water repellent unless the label specifically says that you can. The label often specifies that you use an oil primer.
Several common paintable brands include:

     • Woodlife Classic Clear Wood Preservative
      (Wolman; 800-556-7737; www.wolman.com).

     • Weatherscreen Clear Wood Preservative
      (PPG; 412-434-3131; www.ppg.com).

     • Penofin Exterior Finishes
      (800-736-6346; www.penofin.com).

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Misconception:   Varnish is a good finish for outdoor furniture

Truth:  Nope. Choose varnish for outdoor furniture only if you want to refinish wood as your hobby. Varnishes begin to peel within a year or two when exposed to direct sunlight. Then you have to scrape, sand and refinish to keep the furniture looking good, a timeintensive and laborious task. Sailboat owners do this to keep their mahogany and teak looking sharp, but you probably won’t want to do it as a routine chore. A wipe-on exterior oil finish won’t last as long (perhaps a year), but it’s much easier to renew. (One example is Australian Timber Oil from Cabot, 800-877-8246,www.cabotstain.com.) Every year, simply give the surface a light sanding and reapply the oil.

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Misconception:   Enamel paints are the best choices for woodwork and trim

Truth:   In general, it’s true that enamel is the best choice for trim, but the word enamel can be confusing, and is no longer helpful when you’re making paint decisions. Enamel once referred to resin-rich oil paint, that is, paint that contains a high proportion of oils to make it brush out more smoothly and dry to a glossy finish. Now it can also refer to resin-rich latex paints, which have similar qualities.

To avoid confusion, it’s better to avoid the word enamel and choose your trim paint based on type (oil or latex) and sheen (gloss or semigloss).

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Misconception:   You can’t paint vinyl siding

Truth:  Actually, it’s no problem to paint vinyl siding. The old color won’t peel because the pigments are mostly mixed into the material itself. But it can fade, or you may simply want a color change.

If it’s new and you want to alter the color, wash it with a detergent, then rinse. If it’s older and somewhat faded, you have to be a bit more aggressive. Scrub it with a brush and detergent and water to remove chalking and mildew as well as dirt. Then apply two coats of a 100 percent acrylic paint. You don’t need a primer.

From The Family Handyman - June 2006

 

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