Scrub scrupulously so the stain spreads smoothly
Staining your deck makes the space more inviting for those summer BBQs and increases its durability by protecting it against the elements and minimizing mold. But, without the proper prep work, the coating won’t adhere well, affecting its appearance and longevity. Before you get stuck in with the brushes and rollers, learn how to clean a deck before staining to keep it preserved and polished for years to come.
Taking the time to prep the deck properly means you’ll make the most out of the stain and won’t waste time and money having to restain prematurely. Before you get sucked into scrubbing, take the following steps:
Check the forecast: You want to clean immediately before staining. Avoid the task if there’s rain or high temperatures forecast. Weather should be dry but not so hot that it promotes uneven penetration. Late spring is often the best time to stain a deck, sprucing it up for summer.
Clear the space: Remove all deck furniture and container plants so you have a blank canvas to work with.
Carry out repairs before cleaning: Replacing damaged deck boards or other DIY deck repairs are best done before staining. Call in a local deck repair contractor for the bigger structural overhauls.
Remove previous seal or paint coating: If there’s a layer of sealant or paint on your deck, this needs to come off before you clean and apply any stain.
Follow these steps to clean a wooden deck to have a pristine surface ready for staining (or painting).
Sweep away leaf litter and other dirt before you bring out the cleaning agent. If you see pieces of debris wedged between the boards, use a putty knife to tease them out.
You need to apply some commercial deck cleaners to a dry surface and others to a wet surface. Always check the manufacturer's instructions for use and the length of time it should sit on the deck. You can apply some cleaners directly, and other concentrated formulas need mixing with water. Wear gloves and goggles to protect your eyes and skin.
Alternatively, make a homemade deck cleaner. A mixture of two gallons of warm water and 1/2 cup of distilled white vinegar should do the trick. If there’s a lot of mold and mildew on the deck, mix 1/4 cup of ammonia-free liquid dish soap and 2 cups of oxygen bleach with two gallons of warm water.
Spread the cleaner using a long-handled paint roller, use a pump sprayer, or scrub in with a stiff-bristled brush.
Rinse the cleaner off using a garden hose or low-power pressure washer, spraying in the direction of the wood grain. Overly high pressure can damage wooden surfaces, so stick with a 1,200 to 1,400 psi setting for soft and medium-density wood decks.
If there are any remaining areas of residue, sand your deck to remove them and then rinse again.
Do a last sweep to lift any lingering debris once the deck is fully dry and immediately before you apply the stain.
All the above steps apply for cleaning composite or hardwood (such as Ipe or Batu) decks before staining, but the rinsing technique differs slightly from standard softwood. Composite decks are tougher, so you can use a higher-power pressure washer to help lift any grimy residue or mold. Use a tool with pressure up to 3,100 psi, and hold the wand at least a foot away from the deck boards while using a 40-degree white nozzle tip.
Don't add baking soda to any homemade cleaner in a pressure washer. This granular cleaner can clog up the sprayer nozzle.
Cleaning a deck before staining isn’t rocket science, but there are some things you want to avoid to prevent doing damage or making the job more difficult. These include:
Chlorine bleach: This substance isn’t safe to mix with dish soap and can damage your deck. Only use oxygen bleach when cleaning decks.
High pressure on softwoods: Use a pressure washer on low psi settings up to 1,400 for soft- and mid-density woods, or stick with a stiff-bristled brush and garden hose.
Wire bristle brushes: These can damage the decking. Plastic bristles are tough enough to remove grime, but if you scrub in the direction of the grain, they won’t mark the surface.
Not drying out the deck properly: Before staining, ensure the deck isn’t still damp from washing. It should dry for at least 24 to 48 hours. Trapped moisture leads to poor stain adhesion and the potential for mold and mildew formation.
Deck cleaning is within your reach even if you aren’t a DIY guru. It doesn’t require lots of costly equipment or tricky techniques. With a few basic supplies and a bit of elbow grease, this is a job you can tackle in a couple of hours.
If you don’t want the hassle or are worried about picking the right cleaning products, hire a local deck cleaning service. If you hire a local deck staining contractor, they often include the cost of cleaning in their quote. Average deck staining costs are between $550 and $1,250.
Pressure washing your deck can help to quickly and effectively remove ingrained dirt from the surface. However, if the pressure is too high, you spray against the grain, too close to the surface, or with a narrow nozzle, you can damage the decking surface. Composite decking and hardwoods can handle higher pressure (up to 3,100 psi), but pressure shouldn’t be more than 1,400 psi for softer woods.
If you want to make a deck cleaner from products already in your home, there are various options. The most common is to use a gentle blend of 1 gallon of warm water and 2 tablespoons of ammonia-free dish soap. You can also mix water with distilled vinegar. Sprinkling on some baking soda can help to remove mold and mildew. You can add oxygen bleach (but never damaging chlorine bleach) to the water and ammonia-free dish soap solution for something a bit stronger.
If you don’t clean your deck before staining, dirt and debris can get stuck to the surface—which isn’t a good look. Plus, the stain won’t penetrate the wood properly and won’t do such a good job of protecting the deck from bad weather and UV rays. Basically, the stain won’t last as long or look as good.
