AS PAINTERS use the term, “weathered” wood can refer just as well to the exterior of a dilapidated Victorian home...as to a building addition that was completed just a few weeks ago, but not yet painted. In fact, from a painting standpoint, any type of bare wood that has been exposed to the elements for at least several weeks should be considered weathered wood. Since working with weathered wood can be tricky, anyone planning to do exterior painting of this substrate should keep a few things in mind.

As with any paint job, thorough surface preparation is critical when painting weathered wood. Although it may be tempting to shirk the extra work required to properly prepare the surface , the lasting rewards of a durable paint job make the additional effort worth while . In fact, only through good surface preparation can new paint form a tight, durable and protective bond with the wood substrate below.

Prepare the Surface
As with any previously painted surface, the first step is to scrape away any loose or peeling paint. Then it is important to carefully inspect the building’s exterior for damaged or rotted wood. Dry rot (dry, crumbly sections of wood) and wet rot (soggy, soft spots) are caused by microorganisms weathered wood PQI Magazine j Spring 1996 13 that thrive in damp conditions, just as mildew does. Rot can destroy the wood so completely that a finger can be pushed right into it (poking with a screwdriver can help in locating soft, rotted boards).

Assuming that wood rot is found, all of it should be removed, and the surrounding area treated with a biocide designed for that purpose, before the hole is patched. If this is not done, the rot may continue to grow. Small problem areas can be repaired with wood filler, but wood that is damaged beyond repair must be replaced before proceeding. Any knots or sap pockets in the replacement wood s h o u l d be sealed with shellac to prevent resin bleed-through.

C a u l k
Since wood is susceptible to rot in any area that is excessively wet, further rot can be prevented by making sure that the wood is protected against liquid water. To do so, caulk should be applied to inside and outside corners, joints, seams and other gaps where liquid water could penetrate the wood’s exterior.

The best caulk to recommend for this purpose is a top quality all-acrylic or siliconized acrylic caulk. In addition to their superior flexibility, these caulks (once fully cured) have excellent adhesive properties, which enable them to adhere to a wide range of building materials, even under wet conditions.

Smooth and Clean
The next step is to thoroughly sand and brush off all exposed wood surfaces to remove any degraded wood fibers that may be present. When painting a ridged surface, such as weathered cedar shakes, it may not be possible to reach all of these damaged fibers with sandpaper. In this case, a wire brush can be used to remove as much of the deteriorated surface wood as possible.

Any dust or debris that remains should then be washed off. This can be done by vigorously handwashing the surface with a long-handled brush and warm, soapy water (use a commercial cleaner or ordinary household detergent). The best place to start is at the top of the wall, working down to the bottom. After washing the entire area, immediately and thoroughly rinse it; then move on to the next section.

Although this method is time-consuming, it is effective and low in cost. To speed surface preparation, power washing equipment offers a fast and effective way to rid surfaces of dirt, chalk, mildew — even loose, peeling or flaking paint.

This type of equipment is especially useful when preparing large surfaces for repainting and when cleaning extremely dirty surfaces, such as those that contain stubborn contaminants like grease, soot or salt.

Even new construction is considered “weathered” wood once it has been exposed to the elements for a week or two. Just be sure to stress the importance of following the manufacturer’s instructions to any of your customers who may be considering this option, especially safety recommendations .

Remove Mildew
If mildew is present — and it often is in damp areas that don’t get a lot of sun — it should be treated with a mild bleach solution (one part bleach to three parts water), then rinsed thoroughly.

Use a Quality Primer and Top Quality Paint
The final stage of the process is applying a top quality latex or oil-based primer to the weathered wood surface, followed by one or two coats of top quality acrylic latex exterior paint.

Some woods — like redwood, cypress and red cedar — contain tannins that can bleed through latex paint, causing a brownish stain on the surface. To prevent this, the wood should be primed with a stain-resistant, obliged or acrylic latex primer b e f o re applying the top coat.

When your customer selects the paint, it is essential to consider its quality. A top quality acrylic latex paint is more durable than ordinary house paint, offering better flexibility and adhesion. These traits enable the paint to resist peeling, blistering, cracking and other paint failures.

Investing in the Future
A quality primer and top-of-the-line acrylic latex top coat can help a new paint job look great for up to 10 years or more. And by not having to paint as often, the few extra dollars spent to buy the best paints and primers will actually save your customers money in the long run. SO REMEMBER, weathered doesn’t have to mean withered. Quality products and proper surface preparation can help maintain a home’s glow well into its “golden years.”

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