When did your cedar fence lose its rich, warm glow? Who invited that discolored, shabby-looking impostor into the neighborhood? Don’t worry—underneath that thin gray skin, the glow still remains. All you have to do is remove the surface layer of aged wood cells to expose a fresh layer of wood. With a power washer, it’s as easy as washing your car. Then apply an exterior wood oil stain to preserve this new layer of wood. It’ll prolong the life of your fence to boot.
Power washers are aggressive. They’ll strip the wood as well as clean off the dirt and grime, but you can also erode the wood too deeply and ruin it. The key is to use the right sprayer tip and technique. In any case, the power washer’s spray will slightly raise and roughen the grain on smooth wood. That’s actually good—it allows more sealer to soak in and improves the finish.
Rent a power washer that operates at 1,500 or 2,000 psi and avoid more powerful 3,000 or 3,500 psi units. Be sure to get both 15- and 25-degree spray tips. Have the rental people demonstrate the washer's use. It's an easy machine to run.
To avoid damaging the pump, don't run the power washer without first filling the pump and hoses with water. To do this, attach both hoses (Photo 1), snap in a 25-degree tip, turn on the garden hose spigot and hold down the trigger on the wand until water squirts out. Release the wand trigger and start the engine. If it's hard to pull the start cord, pull the wand trigger to release the water pressure.
Clear the area along the fence by tying back plants that are growing alongside it. Wear water-repellent clothing—you will get wet from the spray.
Start spraying with the wand tip 18 in. from the wood surface. Move in closer as you swing the tip slowly along the length of the board (Photo 2). Keep the width of the fan spray aligned across the boards. The wood's color will brighten as the surface is stripped away. Watch closely and stop stripping when no more color change occurs. You don't have to remove too much surface to expose fresh wood, and continuing to spray won't improve the color.
It takes a little practice to arrive at the proper tip distance and speed of movement, but you'll catch on fast. It's better to make two or three passes than to risk gouging the surface trying to accomplish this job in one pass. As you gain experience, you can switch to a 15-degree tip. This tip cuts more aggressively and works faster than the 25-degree tip.
With the fence clean, it's time to fix or replace damaged boards, refasten loose boards and countersink any protruding nails. Use waterproof glue (Photo 3) to repair any split and broken boards. Drive corrosion-resistant screws (Photo 4) instead of nails to pull loose pieces tightly together. If a gate is sagging, straighten it with a turnbuckle support (Photo 5). Also coat the posts (Photo 6) where they emerge from the ground or concrete with a wood preservative. This is the area that rots first.
To preserve the natural color of the wood, use an exterior semitransparent oil stain. It seals the wood while allowing the grain and color variations to show through. And its pigments add an overall color tone. Make sure the stain contains ultraviolet inhibitors, which will slow down bleaching by sunlight, and a mildewcide to slow fungal growth. Look for samples on cedar at the paint store, or bring in your own piece of wood to test. A test sample is the best way to ensure a satisfactory result.
Before applying the stain, be sure the fence is dry. Allow at least 24 hours. If it's cool and humid, allow another 24 hours.
Use a paint roller with a “medium nap” cover (Photo 7) to apply a soaking coat to the wood. Let the wood absorb as much sealer as it can. Roll about a 3-ft. section of fence and then brush (Photo 8) the sealer into the wood. If the wood still appears dry, roll on additional sealer. Work the sealer into all recesses and corners. The roller applies the stain, but you need the brush to work it well into the wood's surface. Coat detailed areas with a trim roller and smaller brush (Photo 9). Keep wet edges to prevent lap marks.
Most semitransparent oil stains are guaranteed to last two to five years. (Solid-color stains last longer but are more difficult to renew.) Fences usually face severe weathering, so expect the finish to last no more than three years. Plan on recoating the fence within this time frame to keep your fence looking fresh. Before recoating, wash the fence with a garden hose sprayer and use a bristle brush on stubborn dirt deposits and stains. Let the fence dry and stain it using the same method.