Spring Deck Dos: Wash Your Deck

Spring is the perfect time to get your deck clean and ready for the warmer weather ahead. Here are some tips that you can use now to enjoy your deck all summer long.

1. Remove debris from between deck boards using a putty knife. Pay special attention to the areas where deck boards cross the joists — the structural members underneath the decking.

2. Protect all nearby shrubs and plantings. Wet them and cover them with plastic sheeting.

3. Thoroughly sweep the deck.

4. Choose an appropriate cleanser.

• Wood deck: Use a standard deck cleaner and follow its directions. Some require the decking to be wet first. Some don’t.
• Composite deck: Use a cleaner specifically formulated for composite material. Attack grease and oil stains with a commercial degreaser and detergents.
• Vinyl (cellular PVC) deck: You’ll only need to use warm water and a mild soap to remove mold, mildew, and dirt.

5. Clean the deck. Choose a cloudy day when the decking is cool and the sun won’t evaporate the cleaner.

• Wood deck: Use a paint roller, a garden sprayer, or a stiff-bristled brush broom to apply the cleaner. Don’t let it pool. Don’t let the deck dry until you’ve scrubbed it clean. Then let it soak according to manufacturer’s instructions (usually about 10 minutes). Rinse thoroughly with clean water.TIP: To clean wood railings: Working from the bottom up, apply the cleaner, scrub, and then rinse. Working from the top down splatters the cleaning solution onto dry wood where it can double-bleach the surface, leaving marks that don’t go away when the lower area is washed. Working from the bottom up means you’ll be splattering onto a wet surface where the cleaner is diluted, leaving no marks.

• Composite deck: Scrub with a soft brush. Do not use a pressure washer — it can permanently damage the decking and will void any warranty. Remove rust and leaf stains with a deck brightener containing oxalic acid.

• Vinyl deck: Scrub in a circular motion using a stiff broom, then rinse thoroughly.

Power Washing your Deck

• When it’s time to clean your wood deck in preparation for refinishing, a chemical deck brightener applied by hand-scrubbing may not do the job of deep-cleaning, but a power washer will. Often a pressure-washer can effectively clean a deck with just plain water. But a pressure washer can ruin your deck if it’s not used properly. This is a tool that is powerful enough to etch brick, but in the right hands it can also be gentle enough to wash siding. If you use it with too much jet pressure or place the tip too close to the surface of your deck, you can deeply etch the wood and cause the fibers to splinter.

  According to The Spruce, here are three basic steps to doing it right:

  • Pressure and Tip Selection
  • Power Washing
  • Sanding After Washing

  Tools and Supplies You Will Need

  • Pressure washer with a fan tip or rotating tip
  • Deck stripper/brightener (optional)
  • Sheets of plastic (optional)
  • Random orbit sander
  • Sandpaper (60- or 80-grit, 100-grit)

  Note: A pressure washer has many uses around the home, but if you use the tool only rarely, an option is to lease it from a home improvement center or tool rental outlet. It costs about $40 for four hours of use.

  Pressure and Tip Selection

  

  Choose the appropriate pressure setting and spray tip for your application:

  • Use the lowest possible pressure that is still effective. Pressure for soft wood (like cedar or pine) should be at about 500 psi to 600 pounds per square inch (psi); harder woods may tolerate more pressure, but you should not go higher than 1,200 psi.
  • Use a fan tip with a 40- to 60-degree spread. A rotating tip is also suitable if you use it carefully.
  • Test your pressure and its effectiveness in an inconspicuous area, such as a stair tread. If you find it necessary to replace a piece of wood because you etched it, a stair tread is easier to replace than a surface deck board.

  Power Washing

  

  Follow a few tips and safety rules for proper power washing technique:

  1. Start with the pressure at 500 to 600 psi and test it on an inconspicuous area. Increase the pressure incrementally as needed to clean the deck without damaging or etching the wood surface.
  2. Engage the trigger a couple of feet away from the deck surface and then lower the wand to about 12 inches above the surface.
  3. Clean the deck with a sweeping motion of the wand. As you sweep, avoid the tendency to pivot with your arm, which will result in ​an inconsistent distance between the spray tip and the deck surface. Try to maintain a consistent distance by moving your arm laterally back and forth.
  4. Clean from the house outward.
  5. Work with the grain by feathering the spray lengthwise, parallel to the deck boards, and overlapping each area slightly. The goal is to achieve even cleaning with no “hot spots” or visible “cleaning edges.”

Sanding After Washing

Ideally, power washing a wood deck will not ruin the wood and etch or erode the softwood fibers. However, when wood gets wet, the fibers may become raised, creating a rough surface. This is a particular problem on handrails, where the raised fibers can lead to splinters. *** Make sure the wood is dry before sanding.***

You have a couple of options for remedying this problem. If you did a great job of power washing with minimal damage and you just want to clean the deck, you may be able to get away with a spot sanding here and there. But if you are going to refinish (re-stain or reseal) the deck, you will need to sand the entire deck to create smooth boards with little to no splintering. Sanding also opens up the wood’s pores so the wood soaks up the sealer or stain consistently.

When sanding, do not use very fine sandpaper, since this can clog the pores of the wood and prevent the stain/sealer from readily soaking in.  For the handrail, use no finer than 100-grit sandpaper. For the deck surface itself, use a 60- to 80-grit sandpaper. The best sander to use for a wood deck is a random orbital sander with a 5-inch sanding pad.

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